1. A water treatment system, comprising: one or more electrocoagulation (EC) treatment cells (102), and a driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900), the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) comprising: a power circuit electrically coupled to at least one EC treatment cell (102), the power circuit is configured to output DC current; at least one current sensor (118) configured to measure the current flowing through the cell (102) and transmit a current measurement data, wherein the current sensor (118) is coupled to the power circuit; a control circuit electrically coupled to the current sensor (118) and the power circuit, the control circuit is configured to receive the current measurement data from the sensor (118) and provide a pulse width modulation signal based on the current measurement data, and a current drive circuit coupled to the power circuit and the control circuit; the current drive circuit is configured to receive the pulse width modulation signal to allow current of a constant magnitude to flow through the EC treatment cell (102).

2. The system of claim 1, wherein the current drive circuit comprises at least one transistor (126, T1 to T4).

3. The system of claim 1, wherein the current drive circuit comprises a DC to DC converter (132).

4. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises a switch matrix (128) disposed between the power circuit and the EC treatment cell (102), the switch matrix (128) is configured to switch the direction of current to the EC treatment cell (102).

5. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises a comparator bank and one or more logic gates coupled to the comparator bank to measure and transmit the temperature and the pressure of the EC treatment cell (102) to the control circuit.

6. The system of claim 1, wherein the control circuit comprises a microcontroller (120).

7. The system of claim 1, wherein the current sensor (118) is disposed between an output node of the power circuit and the EC treatment cell (102).

8. The system of claim 1, wherein the current sensor (118) is disposed between the transistor (126, T1 to T4) and the EC treatment cell (102).

9. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises at least one of a first ripple filter (108) and a second ripple filter (134) at the output node of the power circuit, the current sensor (118) is disposed between an output node of the ripple filter (108, 134) and the EC treatment cell (102), the current sensor (118) is a hall effect current sensor.

10. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises an opto-isolator (122) connected to the power circuit and the microcontroller (120), the opto-isolator (122) is configured to transmit the pulse width modulation signal to the current control circuit.

Description:TECHNICAL FIELD
[0001] The present invention generally relates to water treatment, and, more particularly, to a system and method for water treatment.

BACKGROUND
[0002] Electrocoagulation is an electrolytic treatment process for separating and removing a broad range of contaminants including metals, solids, pathogens and other undesirable substances from a solution. Generally, an electrocoagulation-based system comprises a pairs of conductive metal plates in parallel that are submerged in an aqueous solution. The plates are connected to a power source to supply direct current.

[0003] During electrolysis, the metal plates used as sacrificial electrodes and continuously produces ions in the water. The released ions neutralize the charges of the particles and thereby initiate coagulation. The released ions remove undesirable contaminants either by causing the colloidal materials to coalesce, which can then be removed by flotation, or any other method. Thus, electrocoagulation is a better process, which removes pollutants from water without using chemicals compared to other conventional water treatment process.

[0004] However, electrocoagulation requires electrodes to feed the current into the solution, which places a lot of strain on the electrodes themselves, resulting in wear and tear. Thus, the magnitude of current is an important factor, which affects the results of the water treatment process. Thus, the system for performing such processes have heretofore required extensive maintenance and investment to assure proper operations. Moreover, some known systems have been inefficiently designed affecting overall operation of the system and plant as well as the system longevity.

[0005] Therefore, there is need for a system and method for water treatment. Further, there is need for a driver circuit for the water treatment system that would address the discussed drawbacks in the conventional electrocoagulation-based water treatment system.

SUMMARY
[0006] The present invention discloses a system and method for water treatment. The system comprises a driver circuit and one or more electrocoagulation (EC) treatment cells. In one embodiment, the system is an electrocoagulation (EC) based water treatment system. The EC treatment cells could be connected in series, or as an array of cells in series and parallel. The driver circuit comprises a power circuit electrically coupled to at least one EC treatment cell. The power circuit is configured to output DC current. The driver circuit further comprises at least one current sensor configured to measure the current flowing through the cell and transmit a current measurement data. The current sensor is coupled to the power circuit.

[0007] The driver circuit further comprises a control circuit electrically coupled to the current sensor and the power circuit. The control circuit is configured to receive the current measurement data from the sensor and provide a pulse width modulation signal based on the current measurement data. The control circuit comprises a microcontroller. The driver circuit further comprises a current drive circuit coupled to the power circuit and the control circuit. The current drive circuit is configured to receive the pulse width modulation signal to allow current of a constant magnitude to flow through the EC treatment cells.

[0008] In one embodiment, the current drive circuit comprises at least one transistor. In another embodiment, the current drive circuit comprises a DC-to-DC converter. The driver circuit further comprises a switch matrix disposed between the power circuit and the EC treatment cell. The switch matrix is configured to switch the direction of current to the EC treatment cells.

[0009] The driver circuit further comprises a comparator bank and one or more logic gates coupled to the comparator bank to measure and transmit the temperature and the pressure of the EC treatment cells to the control circuit. In one embodiment, the current sensor is a hall effect current sensor. In one embodiment, the current sensor is disposed between an output node of the power circuit and the EC treatment cells. In another embodiment, the current sensor is disposed between the transistor and the EC treatment cells. The driver circuit further comprises at least one of first ripple filter and second ripple filter at the output node of the power circuit. In yet another embodiment, the current sensor is disposed between an output node of the ripple filter and the EC treatment cell. The driver circuit further comprises an opto-isolator connected to the power circuit and the microcontroller. The opto-isolator is configured to transmit the pulse width modulation signal to the current control circuit.

BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to an embodiment of the present invention.

[0011] FIG. 2 exemplarily illustrates the driver circuit for the water treatment system of FIG. 1.

[0012] FIG. 3 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to another embodiment of the present invention.

[0013] FIG. 4 exemplarily illustrates the driver circuit for the water treatment system of FIG. 3.

[0014] FIG. 5 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

[0015] FIG. 6 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

[0016] FIG. 7 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

[0017] FIG. 8 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

[0018] FIG. 9 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

[0019] FIG. 10 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

[0020] FIG. 11 exemplarily illustrates a schematic diagram of a driver circuit for a water treatment system, according to yet another embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0021] FIG. 1 to FIG. 5, and FIG. 11, discloses a driver circuit (100, 200, 300, 400, 500, 900) for a water treatment system. The system is an electrocoagulation (EC)-based water treatment system. The system comprises at least one EC treatment cell 102. In another embodiment, the system comprises one or more EC treatment cells 102. The EC treatment cells 102 are connected in series. In some embodiments, the EC treatment cells 102 could be connected in series, or as an array of cells 102 in series and parallel. Referring to FIG. 1, FIG. 2 and FIG. 11, the driver circuit (100, 900) comprises a power circuit configured to supply direct current (DC) voltage to at least one EC treatment cell 102. The power circuit comprises a power source to supply first alternating current (AC) voltage. The power source is at least one of a single-phase AC power source and a three-phase AC power source.

[0022] The power circuit further comprises a first transformer 104, a first rectifier 106, a first ripple filter 108. The first transformer 104, the first rectifier 106 and the first ripple filter 108 are connected in series to the power source. The first transformer 104 receives first AC voltage as input from the power source and converts into second AC voltage. The first transformer 104 steps down the first AC voltage to the second AC voltage. The first rectifier 106 converts the second AC voltage into DC voltage. The first filter 108 is configured to filter the DC voltage from the first rectifier 106. The EC treatment cell 102 receives the filtered DC voltage.

[0023] The driver circuit (100, 900) further comprises a second transformer 110, a second rectifier 112, a first voltage regulator 114 and a second voltage regulator 116. The second transformer 110 receives first AC voltage as input from the power source and converts into second AC voltage. The second transformer 110 is an auxiliary transformer. The second rectifier 112 converts the second AC voltage into auxiliary DC voltage. The first voltage regulator 114 receives the auxiliary DC voltage as input and outputs a first auxiliary DC voltage and the second voltage regulator 116 receives the auxiliary DC voltage as input and outputs a second auxiliary DC voltage.

[0024] The driver circuit (100, 900) further comprises at least one current sensor 118 coupled to the power circuit. In one embodiment, the current sensor 118 is coupled to an output node of the first filter 108. The control circuit further comprises a microcontroller 120 coupled to the current sensor 118. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to receive current measurement data from the current sensor 118. In one embodiment, the current sensor 118 is a hall effect current sensor. The microcontroller 120 is configured to modify the pulse width signal based on the current measurement data from the current sensor 118.

[0025] Referring to FIG. 1 and FIG. 2, the driver circuit 100 further comprises an opto-isolator 122 and a gate driver circuit 124. The microcontroller 120 transmits the pulse width signal to the gate driver circuit 124 via the opto-isolator 122. The second voltage regulator 116 delivers the second auxiliary DC voltage to drive the opto-isolator 122 and the gate driver circuit 124. The gate driver circuit 124 amplifies the pulse width signal from the microcontroller 120. The driver circuit 100 further comprises a current drive circuit. The current diver circuit comprises at least one transistor 126. The transistor 126 receives the amplified pulse width signal from the gate driver circuit 124. Thus, the driver circuit 100 supplies constant current to the EC treatment cell 102. The driver circuit 100 further comprises a switch matrix 128 to switch the direction of current to the EC treatment cell 102.

[0026] The driver circuit 100 further comprises a comparator bank to measure the temperature and the pressure of the EC treatment cell 102. An output from the comparator bank is fed to a logic gate, for example, AND gate 130. The logic gate receives first auxiliary DC power from the first voltage regulator 114. A LOGIC OUT from the logic gate is fed to the microcontroller 120. The microcontroller 120 is configured to determine if the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value. If the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value, the microcontroller 120 shutdown operation of the EC treatment cell 102.

[0027] Referring to FIG. 2, the transistor 126 is a n-type transistor 126. The transistor 126 is selected from group including, but not limited to, power metal–oxide–semiconductor field-effect transistor (Power MOSFET), Bipolar junction transistor (BJT) and Insulated Gate Bipolar Transistor (IGBT). A source of the n-type transistor 126 is connected to a ground and the gate of the n-type transistor 126 is connected to the gate driver circuit 124.

[0028] Referring to FIG. 3 and FIG. 4, the driver circuit 200 comprises the power circuit configured to supply direct current (DC) voltage to at least one EC treatment cell 102. The power circuit comprises the power source to supply first alternating current (AC) voltage. The power circuit further comprises the first transformer 104, the first rectifier 106, the first ripple filter 108. The first transformer 104, the first rectifier 106 and the first ripple filter 108 are connected in series to the power source. The first transformer 104 receives first AC voltage as input from the power source and converts into second AC voltage. The first transformer 104 steps down the first AC voltage to the second AC voltage. The first rectifier 106 converts the second AC voltage into DC voltage. The first filter 108 is configured to filter the DC voltage from the first rectifier 106. The EC treatment cell 102 receives the filtered DC voltage. The driver circuit 200 further comprises the second transformer 110, the second rectifier 112, the first voltage regulator 114 and the second voltage regulator 116. The second transformer 110 receives first AC voltage as input from the power source and converts into second AC voltage. The second transformer 110 is an auxiliary transformer. The second rectifier 112 converts the second AC voltage into auxiliary DC voltage. The first voltage regulator 114 receives the auxiliary DC voltage as input and outputs a first auxiliary DC voltage and the second voltage regulator 116 receives the auxiliary DC voltage as input and outputs a second auxiliary DC voltage.

[0029] The driver circuit 200 further comprises at least one current sensor 118 between the EC treatment cells 102 and the transistor 126. In one embodiment, the current sensor 118 is coupled to a path between the EC treatment cells 102 and the transistor 126. The control circuit further comprises the microcontroller 120 coupled to the current sensor 118. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to receive current measurement data from the current sensor 118. In one embodiment, the current sensor 118 is a hall effect current sensor. The microcontroller 120 is configured to modify the pulse width signal based on the current measurement data from the current sensor 118.

[0030] The driver circuit 200 further comprises the opto-isolator 122 and the gate driver circuit 124. The microcontroller 120 transmits the pulse width signal to the gate driver circuit 124 via the opto-isolator 122. The second voltage regulator 116 delivers the second auxiliary DC voltage to drive the opto-isolator 122 and the gate driver circuit 124. The gate driver circuit 124 amplifies the pulse width signal from the microcontroller 120. The driver circuit 200 further comprises the current drive circuit. The current diver circuit comprises at least one transistor 126. The transistor 126 receives the amplified pulse width signal from the gate driver circuit 124. Thus, the driver circuit 200 supplies constant current to the EC treatment cell 102. The driver circuit 200 further comprises the switch matrix 128 to switch the direction of current to the EC treatment cell 102.

[0031] The driver circuit 200 further comprises the comparator bank to measure the temperature and the pressure of the EC treatment cell 102. An output from the comparator bank is fed to the logic gate, for example, AND gate 130. The logic gate receives first auxiliary DC power from the first voltage regulator 114. A LOGIC OUT from the logic gate is fed to the microcontroller 120. The microcontroller 120 is configured to determine if the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value. If the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value, the microcontroller 120 shutdown operation of the EC treatment cell 102.

[0032] Referring to FIG. 4, the transistor 126 is a n-type transistor 126. The transistor 126 is selected from group including, but not limited to, power metal–oxide–semiconductor field-effect transistor (Power MOSFET), bipolar junction transistor (BJT) and Insulated Gate Bipolar Transistor (IGBT). A source of the n-type transistor 126 is connected to a ground and the gate of the n-type transistor 126 is connected to the gate driver circuit 124. The current sensor 118 is connected to the n-type transistor 126 and the EC treatment cell 102. The driver circuit 100, 200 is a pulsed current drive with low side drive. The driver circuit 100, 200 is constant current drive implies that the current waveform is time varying, but its average value is maintained constant. Referring to FIG. 1 to FIG. 4, in another embodiment, the transistor 126 is a bipolar junction transistor.

[0033] Referring to FIG. 5, FIG. 6, and FIG. 7, a driver circuit 300, 400, 500 comprises the power circuit configured to supply direct current (DC) voltage to at least one EC treatment cell 102. The power circuit comprises the power source to supply first alternating current (AC) voltage. The power circuit further comprises the first transformer 104, the first rectifier 106, the first ripple filter 108. The first transformer 104, the first rectifier 106 and the first ripple filter 108 are connected in series to the power source. The first transformer 104 receives first AC voltage as input from the power source and converts into second AC voltage. The first transformer 104 steps down the first AC voltage to the second AC voltage. The first rectifier 106 converts the second AC voltage into DC voltage. The first filter 108 is configured to filter the DC voltage from the first rectifier 106. The rectified DC voltage is then chopped and turned into a pulsed signal of high frequency. The pulsed signal is then stepped down by a pulse transformer which is then rectified.

[0034] The driver circuit 300, 400, 500 further comprises the second transformer 110, the second rectifier 112, the first voltage regulator 114 and the second voltage regulator 116. The second transformer 110 receives first AC voltage as input from the power source and converts into second AC voltage. The second transformer 110 is an auxiliary transformer. The second rectifier 112 converts the second AC voltage into auxiliary DC voltage. The first voltage regulator 114 receives the auxiliary DC voltage as input and outputs a first auxiliary DC voltage and the second voltage regulator 116 receives the auxiliary DC voltage as input and outputs a second auxiliary DC voltage. The driver circuit 300, 400, 500 is a DC current drive, in which the current waveform is constant in time.

[0035] Referring to FIG. 5 and FIG. 6, the driver circuit 300, 400 further comprises a DC-to-DC converter 132. An output DC voltage from the DC-to-DC converter 132 is filtered using a second ripple filter 134 and transmitted to the EC treatment cell 102. The driver circuit 300, 400 further comprises a control circuit. The control circuit further comprises the microcontroller 120 coupled to the current sensor 118. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to receive current measurement data from the current sensor 118. In one embodiment, the current sensor 118 is a hall effect current sensor. The microcontroller 120 is configured to modify the pulse width signal based on the current measurement data from the current sensor 118. The control circuit further comprises a chopping circuit to control the frequency of the chopped signal.

[0036] Referring to FIG. 5, the driver circuit 300 comprising the current sensor 118. The current sensor 118 is disposed between the EC treatment cell 102 and the microcontroller 120. The driver circuit 300 further comprises the opto-isolator 122 configured to receive the pulse width signal from the microcontroller 120, which is delivered to the DC-to-DC converter 132. The opto-isolator 122 is configured to receive second auxiliary DC voltage from the second volage regulator 116. Thus, the driver circuit 300 supplies constant current to the EC treatment cell 102.

[0037] Referring to FIG. 6, the driver circuit 400 comprising the current sensor 118. The current sensor 118 is coupled to an output node of the second ripple filter 134 and to the microcontroller 120. The driver circuit 400 further comprises the opto-isolator 122 configured to receive the pulse width signal from the microcontroller 120, which is delivered to the DC-to-DC converter 132. The opto-isolator 122 is configured to receive second auxiliary DC voltage from the second volage regulator 116. Thus, the driver circuit 400 supplies constant current to the EC treatment cell 102.

[0038] Referring to FIG. 5 and FIG. 6, the driver circuit 300, 400 further comprises the switch matrix 128 to switch the direction of current to the EC treatment cell 102. The driver circuit 300, 400 further comprises the comparator bank to measure the temperature and the pressure of the EC treatment cell 102. An output from the comparator bank is fed to the logic gate, for example, AND gate 130. The logic gate receives first auxiliary DC power from the first voltage regulator 114. A LOGIC OUT from the logic gate is fed to the microcontroller 120. The microcontroller 120 is configured to determine if the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value. If the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value, the microcontroller 120 shutdown operation of the EC treatment cell 102.

[0039] Referring to FIG. 7, the driver circuit 500 further comprises at least one current sensor 118, and the current diver circuit comprising at least one transistor 126. The transistor 126 is coupled to an output node of the first ripple filter 108. The control circuit further comprises the microcontroller 120 coupled to the current sensor 118. The current sensor 118 is configured to measure the current supplied to the EC cells 102 and transmit the current measurement data to the microcontroller 120. In one embodiment, the current sensor 118 is a hall effect current sensor. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to modify the pulse width signal based on the current measurement data from the current sensor 118. The current sensor 118 is disposed at a path between the transistor 126 and the EC treatment cells 102.

[0040] The driver circuit 500 further comprises the opto-isolator 122 and a high side gate driver circuit 136. The microcontroller 120 transmits the pulse width signal to the gate driver circuit 136 via the opto-isolator 122. The control circuit further comprises a chopping circuit to control the frequency of the chopped signal. The second voltage regulator 116 delivers the second auxiliary DC voltage to drive the opto-isolator 122 and the gate driver circuit 136. The gate driver circuit 136 amplifies the pulse width signal from the microcontroller 120. Thus, the driver circuit 500 supplies constant current to the EC treatment cell 102.

[0041] The driver circuit 500 further comprises the switch matrix 128 to switch the direction of current to the EC treatment cell 102. The driver circuit 500 further comprises the comparator bank to measure the temperature and the pressure of the EC treatment cell 102. An output from the comparator bank is fed to the logic gate, for example, AND gate 130. The logic gate receives first auxiliary DC power from the first voltage regulator 114. A LOGIC OUT from the logic gate is fed to the microcontroller 120. The microcontroller 120 is configured to determine if the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value. If the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value, the microcontroller 120 shutdown operation of the EC treatment cell 102.

[0042] Referring to FIG. 1, FIG. 2 and FIG. 6, the current sensor 118 placed adjacent to the ripple filter (134, 108) to sense the inductor current. The current sensor 118 is configured to directly sense the average value of the current. The current sensor 118 sensing the inductor current could be a sensor rated for lower current values thereby saving cost and space. Alternatively, referring to FIG. 3, FIG. 4, FIG. 5 and FIG. 7, the current sensor 118 is placed in the path between the electrocoagulation cells 102, the transistor 126 and the ground. According to this configuration, the current sensor 118 is configured to sense a waveform, which is further have to be averaged by the microcontroller 120.

[0043] Referring to FIG. 8, a driver circuit 600 comprises a power circuit configured to supply direct current (DC) voltage to at least one EC treatment cell 102. The power circuit comprises a power source to supply first alternating current (AC) voltage. The power circuit further comprises the first rectifier 106, the first ripple filter 108, the DC-to-DC converter 132, and the second ripple filter 134. The first rectifier 106, the first ripple filter 108, the DC-to-DC converter 132, and the second ripple filter 134 are connected in series to the power source. The first rectifier 106 converts the first AC voltage into the DC voltage. The first ripple filter 108 is configured to filter the DC voltage from the first rectifier 106. The output DC voltage from the first ripple filter 108 is input into the DC-to-DC converter 132. An output DC voltage from the DC-to-DC converter 132 is filtered using the second ripple filter 134 and transmitted to the EC treatment cell 102.

[0044] The driver circuit 600 further comprises the second transformer 110, the second rectifier 112, the first voltage regulator 114 and the second voltage regulator 116. The second transformer 110 receives the first AC voltage as input from the power source and converts into the second AC voltage. The second transformer 110 is an auxiliary transformer. The second rectifier 112 converts the second AC voltage into auxiliary DC voltage. The first voltage regulator 114 receives the auxiliary DC voltage as input and outputs a first auxiliary DC voltage and the second voltage regulator 116 receives the auxiliary DC voltage as input and outputs the second auxiliary DC voltage.

[0045] The driver circuit 600 further comprises at least one current sensor 118 coupled to the power circuit. In one embodiment, the current sensor 118 is coupled to an output node of the second ripple filter 134. The control circuit further comprises the microcontroller 120 coupled to the current sensor 118. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to receive current measurement data from the current sensor 118. In one embodiment, the current sensor 118 is a hall effect current sensor. The microcontroller 120 is configured to modify the pulse width signal based on the current measurement data from the current sensor 118.

[0046] The driver circuit 600 further comprises the opto-isolator 122 and the gate driver circuit 124. The microcontroller 120 transmits the pulse width signal to the gate driver circuit 124 via the opto-isolator 122. The second voltage regulator 116 delivers the second auxiliary DC voltage to drive the opto-isolator 122 and the gate driver circuit 124. The gate driver circuit 124 amplifies the pulse width signal from the microcontroller 120. The driver circuit 600 further comprises a current drive circuit. The current diver circuit comprises at least one transistor 126. The transistor 126 receives the amplified pulse width signal from the gate driver circuit 124. Thus, the driver circuit 600 supplies constant current to the EC treatment cell 102. The driver circuit 600 further comprises a switch matrix 128 to switch the direction of current to the EC treatment cell 102.

[0047] FIG. 9 exemplarily illustrates a schematic diagram of a driver circuit 700 for a water treatment system, according to yet another embodiment of the present invention. FIG. 10 exemplarily illustrates a schematic diagram of a driver circuit 800 for a water treatment system, according to yet another embodiment of the present invention.

[0048] Referring to FIG. 9 and FIG. 10, the driver circuit (700, 800) comprises a power circuit configured to supply direct current (DC) voltage to at least one EC treatment cell 102. The power circuit comprises a power source to supply first alternating current (AC) voltage. The power circuit comprises the first rectifier 106, a chopping circuit 702, a power transformer 704, a third rectifier 706 and the second ripple filter 134. The first rectifier 106, the chopping circuit 702, the power transformer 704, the third rectifier 706 and the second ripple filter 134 are connected in series to the power source. The first rectifier 106 converts the first AC voltage into the DC voltage. The chopping circuit 702 received the DC voltage and chops the DC voltage into high frequency pulses, for example, frequency greater than the 50Hz/60 Hz line power.

[0049] The high frequency pulse could be adjusted, for example, stepped up, or stepped down to a desired value, via the power transformer 704. The power transformer 704 is configured to provide pulsed output voltage. The third rectifier 706 is configured to rectify the pulsed voltage from the transformer 704 and the ripple is filtered using the second ripple filter 134. The DC power/voltage from the ripple filter 134 is configured to power the EC treatment cells 102.

[0050] The driver circuit (700, 800) further comprises the second transformer 110, the second rectifier 112, the first voltage regulator 114 and the second voltage regulator 116. The second transformer 110 receives first AC voltage as input from the power source and converts into second AC voltage. The second transformer 110 is an auxiliary transformer. The second rectifier 112 converts the second AC voltage into auxiliary DC voltage. The first voltage regulator 114 receives the auxiliary DC voltage as input and outputs a first auxiliary DC voltage and the second voltage regulator 116 receives the auxiliary DC voltage as input and outputs the second auxiliary DC voltage.

[0051] Referring to FIG. 9, the driver circuit 700 further comprises at least one current sensor 118 coupled to the power circuit. In one embodiment, the current sensor 118 is coupled to an output node of the second ripple filter 134. The control circuit further comprises the microcontroller 120 coupled to the current sensor 118. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to receive current measurement data from the current sensor 118. The current measurement data includes an average current through the cells 102 measured at the inductor of the second ripple filter 134. To ensure the current is constant, the microcontroller 120 provides a feedback signal to the chopping circuit 702 and adjusts the frequency of the chopper circuit 702, which then adjusts the voltage at the output of the power transformer 704. Thus, the driver circuit 700 eliminates the expensive, large input transformer which works on 50Hz/60Hz power.

[0052] In one embodiment, the current sensor 118 is a hall effect current sensor. The microcontroller 120 is configured to modify the pulse width signal based on the current measurement data from the current sensor 118. The driver circuit 700 further comprises the opto-isolator 122 and the gate driver circuit 124. The opto-isolator 122 and the gate driver circuit 124 is configured to receive second auxiliary DC supply. The microcontroller 120 provides feedback signal to the chopping circuit 702 through the opto-isolator 122 and the gate driver circuit 124.

[0053] Referring to FIG. 10, the driver circuit 800 further comprises at least one current sensor 118 coupled to the power circuit. In one embodiment, the current sensor 118 is coupled to an output node of the second ripple filter 134. The control circuit further comprises the microcontroller 120 coupled to the current sensor 118. The first voltage regulator 114 delivers the first auxiliary DC voltage to the microcontroller 120. The microcontroller 120 is configured to receive current measurement data from the current sensor 118. The driver circuit 800 further comprises the opto-isolator 122 and the gate driver circuit 124. The opto-isolator 122 and the gate driver circuit 124 is configured to receive second auxiliary DC supply.

[0054] The gate driver circuit 124 amplifies the pulse width signal from the microcontroller 120. The driver circuit 800 further comprises a current drive circuit. The current diver circuit comprises at least one transistor 126. The transistor 126 receives the amplified pulse width signal from the gate driver circuit 124. Thus, the driver circuit 800 supplies pulsed current to the EC treatment cell 102. The driver circuit 800 further comprises a second gate driver 708 and a second opto-isolator 710. The microcontroller 120 provides feedback signal to the chopping circuit 702 through the opto-isolator 708 and the gate driver 710 to control the DC voltage. Thus, the driver circuit 800 is configured to control both current level and the DC voltage supplied to the EC treatment cell 102 and provides optimum power drive.

[0055] Referring to FIG. 8, FIG. 9 and FIG. 10, the driver circuit 600, 700, 800 further comprises a comparator bank to measure the temperature and the pressure of the EC treatment cell 102. An output from the comparator bank is fed to a logic gate, for example, AND gate 130. The logic gate receives first auxiliary DC power from the first voltage regulator 114. A LOGIC OUT from the logic gate is fed to the microcontroller 120. The microcontroller 120 is configured to determine if the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value. If the temperature and the pressure of the EC treatment cell 102 exceeds the reference measurement value, the microcontroller 120 shutdown operation of the EC treatment cell 102.

[0056] Referring to FIG. 11, the driver circuit 900 comprises an opto-isolator 122, a gate driver circuit 124, a second opto-isolator 710 and a second gate driver 708. The second voltage regulator 116 delivers the second auxiliary DC voltage to drive the opto-isolator 122, the gate driver circuit 124, the second opto-isolator 710 and a second gate driver 708. The driver circuit 900 comprises at least four transistors (T1, T2, T3, T4) that are configured to act as switches. In one embodiment, the transistors (T1, T2, T3, T4) are insulated-gate bipolar transistors (IGBTs). In another embodiment, the transistors (T1, T2, T3, T4) are Metal Oxide Silicon Field Effect Transistors (MOSFETs). In yet another embodiment, the transistors (T1, T2, T3, T4) could be any power transistors.

[0057] The electrocoagulation cells 102 are connected in the manner such that the current path from the power source to ground is via the transistor T1, through the electrocoagulation cells 102, through transistor T4 and to the ground. Alternatively, the current path is through transistor T3, through the electrocoagulation cells 102 (but in the opposite direction), through transistor T2 and to the ground. The transistors T1 and T4 receive signal SIG A, and transistors T2 and T3 are receive SIG B from two different optocoupler-gate driver circuits (122, 124, 710, 708). The optocoupler-gate driver circuits (122, 124, 710, 708) are controlled by the microcontroller 120. Thus, at any given time, if transistors T1 and T4 are driven by the pulse width modulated (PWM) gate signal SIG A, T2 and T3 are off, i.e., SIG B supplies a voltage that keeps T2 and T3 off. On the other hand, if T2 and T3 are driven by the pulse width modulated gate signal SIG B, T1 and T4 are off, i.e., SIG A supplies a voltage to keep T1 and T4 off.

[0058] The usefulness of the circuit 900 is that while the pulse width modulation could be used to control the current through the circuit 900, the four transistors (T1, T2, T3, T4) (T1, T2, T3, T4 also referred as T1 to T4) allow polarity reversal i.e., they permit the flow of current in both directions through the electrocoagulation cells 102. The microcontroller 120 receives a polarity reversal signal. If polarity reversal is high, the microcontroller 120 instructs the optocoupler-gate driver (122, 124, 710, 708) to supply the PWM to SIG A, and set SIG B at a voltage which keeps the transistors T2 and T3 off. If polarity reversal is low, the microcontroller 120 instructs the optocoupler-gate driver (122, 124, 710, 708) to supply the PWM to SIG B, and set SIG A at a voltage which keeps transistors T1 and T4 off.

[0059] In one embodiment, the present invention further discloses a method for water treatment. The method is incorporated in the system comprising one or more electrocoagulation (EC) treatment cells (102), and the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900). The driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) comprises the power circuit electrically coupled to at least one EC treatment cell (102), the current sensor (118) coupled to the power circuit, the control circuit electrically coupled to the current sensor (118) and the power circuit, and the current drive circuit coupled to the power circuit and the control circuit. The control circuit comprises a microcontroller (120). The current sensor (118) is disposed between an output node of the power circuit and the EC treatment cell (102). In another embodiment, the current sensor (118) is disposed between the transistor (126) and the EC treatment cell (102).

[0060] The driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises at least one of a first ripple filter (108) and a second ripple filter (134) at the output node of the power circuit. In yet another embodiment, the current sensor (118) is disposed between an output node of the ripple filter (108, 134) and the EC treatment cell (102). The driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises an opto-isolator (122) connected to the power circuit and the microcontroller (120).

[0061] At one step, the power circuit is configured to output DC current. At another step, at least one current sensor (118) is configured to measure the current flowing through the cell (102) and transmit a current measurement data. At yet another step, the control circuit is configured to receive the current measurement data from the sensor (118) and provide a pulse width modulation signal based on the current measurement data. At yet another step, the current drive circuit is configured to receive the pulse width modulation signal to allow current of a constant magnitude to flow through the EC treatment cell (102).

[0062] The current drive circuit further comprises at least one transistor (126) and a DC-to-DC converter (132). The driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises a switch matrix (128) disposed between the power circuit and the EC treatment cell (102). At yet another step, the switch matrix (128) is configured to switch the direction of current to the EC treatment cell (102). The driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises a comparator bank and one or more logic gates coupled to the comparator bank to measure and transmit the temperature and the pressure of the EC treatment cell (102) to the control circuit. At yet another step, the opto-isolator (122) is configured to transmit the pulse width modulation signal to the current control circuit.
, Claims:We Claim:
1. A water treatment system, comprising:
one or more electrocoagulation (EC) treatment cells (102), and a driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900), the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) comprising:

a power circuit electrically coupled to at least one EC treatment cell (102), the power circuit is configured to output DC current;

at least one current sensor (118) configured to measure the current flowing through the cell (102) and transmit a current measurement data, wherein the current sensor (118) is coupled to the power circuit;

a control circuit electrically coupled to the current sensor (118) and the power circuit, the control circuit is configured to receive the current measurement data from the sensor (118) and provide a pulse width modulation signal based on the current measurement data, and

a current drive circuit coupled to the power circuit and the control circuit; the current drive circuit is configured to receive the pulse width modulation signal to allow current of a constant magnitude to flow through the EC treatment cell (102).

2. The system of claim 1, wherein the current drive circuit comprises at least one transistor (126, T1 to T4).

3. The system of claim 1, wherein the current drive circuit comprises a DC to DC converter (132).

4. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises a switch matrix (128) disposed between the power circuit and the EC treatment cell (102), the switch matrix (128) is configured to switch the direction of current to the EC treatment cell (102).

5. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises a comparator bank and one or more logic gates coupled to the comparator bank to measure and transmit the temperature and the pressure of the EC treatment cell (102) to the control circuit.

6. The system of claim 1, wherein the control circuit comprises a microcontroller (120).

7. The system of claim 1, wherein the current sensor (118) is disposed between an output node of the power circuit and the EC treatment cell (102).

8. The system of claim 1, wherein the current sensor (118) is disposed between the transistor (126, T1 to T4) and the EC treatment cell (102).

9. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises at least one of a first ripple filter (108) and a second ripple filter (134) at the output node of the power circuit, the current sensor (118) is disposed between an output node of the ripple filter (108, 134) and the EC treatment cell (102), the current sensor (118) is a hall effect current sensor.

10. The system of claim 1, wherein the driver circuit (100, 200, 300, 400, 500, 600, 700, 800, 900) further comprises an opto-isolator (122) connected to the power circuit and the microcontroller (120), the opto-isolator (122) is configured to transmit the pulse width modulation signal to the current control circuit.