FIELD OF INVENTION
This invention relates to power backup system for a lift / elevator. More particularly, the present invention provides an improved power backup system for a lift/ elevator with a long-lasting secondary power source.
BACKGROUND & PRIOR ART
With the globalization of the elevator industry, there has been a trend to standardize the elevator systems worldwide. This trend is leaning towards the use of traction systems for smaller elevator applications (i.e., fewer floors). Previously, hydraulic elevator systems were commonly used in applications with over five landings. The trend anticipates that, these applications will begin to utilize traction elevator systems. Such systems must be provided with emergency or back-up power systems that supply power not only to the controller, door operator and valves, but also to the main drive system.
Many common back-up Universal Power Systems (UPS) use a high frequency waveform synthesis to create a near perfect three phase sine wave output waveform. This approach requires an expensive design. This approach can also cause problems for an elevator control system, as there will be high frequency noise and potentially a larger than expected number of zero crossings.
The present invention overcomes the disadvantages of the common back-up UPS by providing a stepped square wave output. Therefore, the invention provides the power required with a much simpler and cost effective design.
Reference may be made to the following known arts:
US patent no 4,520,343 relates to the lift control system. The invention describes a system which can detect various events, such as movement of people or articles, fire break out, undesirable heat generation, panic caused by violence or the like occurring inside a cage or on a floor in front of the cage with its door being
opened and which can control the lift, including the door, in such a manner as to cope with such events. This patent does not talks about power back up.
US patent no 5,130,617 is directed to an inverter control device for controlling the induction motor that drives elevators. The inverter has two induction motor coils that are electrically separate. Special inverters are connected to each coil. There is a control device that controls these two inverters with the same current command. This is a doubly fed drive.
US patent no 7,275,622 discloses an emergency back-up power system for a traction elevator. A back-up power system for a traction elevator includes a power sensing device to sense a power loss or irregularity of the normal control power. An inverter timing system is connected to the power loss sensing device. The inverter timing system receives a power sensing signal from the power sensing device. A back-up power generating system communicates with the inverter timing system and generates an output to provide a back-up power to the elevator system. The invention is complicated and does not provide monitoring of the system. This backup system does not include user settable rescue mode operation, data logging, and remote monitoring.
US patent no 6,827,182 describes an elevator control apparatus which, when a power failure of the A.C. power source is detected, effectively and usefully uses the stored power in a power accumulator. When the A.C. power source is restored, it returns the elevator back to the original service to make the proper operation possible. The control system includes a control for, when a power failure is detected with a power failure detector, supplying power from the power accumulator to an inverter, to control circuits and to an illumination circuit of the elevator with a charge/discharge control circuit to continue the operation of the elevator. This backup system does not includes user settable rescue mode operation, data logging, and remote monitoring.
US patent no 6,533,074 relates to an elevator control apparatus capable of uniformly charging the power storage unit. The control apparatus includes a converter, an inverter, a controller for controlling a motor based on AC power. The motor has a variable voltage and a variable frequency supplied from the inverter and is operating an elevator. With the present invention, the charge/discharge control circuit sets the discharge amount of the power storage unit to a preset maximum value until a preset reference value of a charge state is reached, immediately following the completion of the uniform charging. This is a variable voltage-frequency motor drive providing the back up also, but there is no settable rescue time type of concept and monitoring invention
US patent no 6,439,347 discloses an elevator control apparatus utilizing a power storage unit. An elevator control apparatus is provided that includes a converter for rectifying AC power into DC power; an inverter for converting the DC power into AC power of a variable voltage and a variable frequency and a controller. This is a variable voltage-frequency motor drive providing the back up also, but there is no settable rescue time type of concept and monitoring invention
US publication no 2010044160 relates to a system which continuously drives an elevator hoist motor during normal and power failure operating conditions. A regenerative drive delivers power to the hoist motor from a main power supply during the normal operating condition and from a backup power supply during the power failure operating condition. A controller operates the regenerative drive to provide available power on the regenerative drive to the backup power supply during the normal operating condition. This is a hoist motor drive. This also provides the back up, but there is no settable rescue time and graphical user interface.
US publication no 2010006378 discloses a system which continuously drives an elevator hoist motor during normal and power failure conditions. A regenerative drive delivers power from a main power supply to the hoist motor during normal operation. A rescue operation circuit includes a backup power supply and is operable in the event of a failure of the main power supply to disconnect the
regenerative drive from the main power supply and connect the back up power supply to the regenerative drive to provide substantially uninterrupted power to the hoist motor. This backup system has no settable rescue time management, graphical user interface and remote access feature.
Publication no. KR20090087064 is directed to a system that continuously drives an elevator hoist motor during normal and power failure conditions. A regenerative drive delivers power from a main power supply to the hoist motor during normal operation. A rescue operation circuit includes a backup power supply and is operable in the event of a failure of the main power supply to disconnect the regenerative drive from the main power supply and connect the back up power supply to the regenerative drive to provide substantially uninterrupted power to the hoist motor. This backup system has no settable rescue time management, graphical user interface and remote access feature.
Publication no. WO2009085288 relates to a method of controlling an elevator system comprises transferring power to an elevator car from a primary power supply to a backup power supply without interruption of power if the primary power supply fails or is disrupted. Following transfer of power'to the elevator car from the primary power supply to the backup power supply either pending operations of the elevator car are completed or the elevator car is moved to a predetermined floor based on pending operations of the elevator car. The backup power supply can be attached to the elevator car. This invention does not talk about data logging and remote access of the total system.
Publication no. CN101340106 relates to a power supply system for an elevator that includes: an inverter device which inverts sine-wave power supplied from an industrial power source to a rectangular wave to output; a storage battery which stores power of the industrial power source while normal operation and offers the stored power to the inverter device upon power failure. This is a back up power supply, having preset rescue time. The present invention talks about user settable rescue time.
Publication no. JP2009221005 relates to recording suspicious action even if the suspicious action is performed with respect to a monitoring camera in a car. A sensor 12 of an abnormal condition detection section 8 in a camera unit 1 outputs an abnormal condition detection signal to a recording processing section 5 when the physical abnormal condition of the camera unit 1 is detected by a contact sensor, a power shutdown detection circuit, and an acceleration sensor. When the recording processing section 5 detects the abnormal condition detection signal, image information within time going back by a constant time from a period when detecting the abnormal condition detection signal, stored in an RAM 9 for operation in a backup recording unit 10, is copied and stored in a flash memory 7 so that the image information from a detecting period to a paint of time going back by a constant set time is recorded and stored in the backup recording unit 10 regardless of passage of time after detection. This is just the control and data logging invention, but there is no back up to the elevator incase of mains absence.
Publication no. JP2009298546 relates to a control system for an elevator, capable of sending operation information on the elevator according to an emergency operation at long-period oscillation to a remote monitoring center when the emergency operation at long-period oscillation is performed due to a long-period ground motion, strong wind, or the like, thereby enabling efficient recovery by a dedicated engineer. This invention is a control system which detects, controls and transmits the messages regarding the unnatural events occurred in the elevator
Publication no. JP2009274845 relates to a maintenance center device and an elevator control device for remotely monitoring a plurality of kinds of elevators. This invention talks about elevator control
Publication no. CN101551658 relates to an elevator energy consumption monitoring device provided with a plurality of energy consumption monitoring units wirelessly connected with a centralized monitoring center. This is an energy meter and monitoring invention.
Publication No. CN201184972 relates to an energy consumption monitoring device for an elevator.
US Patent No. 7,549,515 relates to an elevator rescue system comprising an emergency power supply, an emergency brake switch for connecting and disconnecting the power of the emergency power supply to the brake, and an emergency drive switch for connecting and disconnecting the power of the emergency power supply to the drive motor. In this invention, there is no user settable option, graphical display and remote monitoring system.
US Patent No. 7,681,693 relates to a method for performing an elevator rescue run in an emergency situation, the elevator comprising an elevator car, a counterweight, a rope suspending the car and the counterweight, a drive motor, an emergency brake for stopping the car in an emergency situation and a motor drive unit for supplying drive power to and for controlling the drive motor, as well as a corresponding elevator. There is no emergency power supply. This invention is related to the mechanical control.
US Patent No. 7,690,483 relates to an elevator comprising a car, a drive motor driving the car, a motor drive unit for controlling the drive motor and supplying power thereto, an encoder for sensing movement of the car, an elevator rescue system for rescue operation in case of an emergency situation, and particularly for moving a car to a landing in case of an emergency situation.
Reference may be made to the product by "Swastik Power Electronics (India) Private Limited ". The product explains microcontroller based, low cost sine wave lift inverter with a three phase balanced & unbalanced load and SMPS charger.
Further, reference may be made to an article by "Soyo Systems, Maharashtra, India". The Soyo Systems proposes a technically advanced range of lift backup inverters that efficiently provide the function of an emergency lift operating system. The use of advanced technologies and superior engineering in its construction makes them ideal for operation in all weather conditions.
Reference may be made to an article by "Fuji Electric FA Europe". The article explains FRENIC Lift inverter to fulfill the requirements of lift applications. It includes the most advanced technology to offer a product that is easy to set up, is powerful and competitive. FRENIC Lift is the name of the technology and quality dedicated to elevator applications.
Reference may be made to an article by "Kevin Power Solutions (P) Ltd ". The article explains, a 3 phase DSP Sine Wave Inverter designed to generate 3 phase 4 wire OUT PUT to support Lifts/Elevators during utility failure. In addition to this, important loads like staircase, parking, compound & common light and security system can be run through this innovative product. KEVIN ALBS is a unique combination of DSP SINE WAVE 3 phase inverter, storage, battery charger and an electronics change over module. It uses solid state static switches and has almost zero failure. High end DSP based design provides fast control. Automatic load sensing will stop indoor open condition at the time of low battery protection.
Reference may be made to the product by "Foshan Mueller & Mico Elevator Technology Co Ltd". The product presents a lift inverter which is a Vector-controlled frequency inverter. It has minimal noise, anti- interference performance, four-quadrant controlled, easy inspection, auto-calculating braking distance, smaller size and derived with three-phase AC synchronous motor.
Again, reference may be made to the products by "Technovision Energy Pvt Ltd ". The article explains lift inverters which do not emit smoke any other kind of gases that are harmful to the environment. Further these do not generate noise. This makes them preferred power backup products also. Apart from this, some other features that make them useful products include high reliability, flexibility and easy adaptability.
Thus, the lift system requires that the back-up power system provides full power to the system. This requires that the back-up power system should be capable of
switching to high power load. A different system approach for controlling the lift is needed so as to assure that the back-up power system logs the details of the lift and provides the information to the user as per requirement.
With all the above discussed restrictions or limitations, it is required to have a power backup system which continuous monitors the lift/ elevator, and is able to keep track of which direction the lift/ elevator would drift. When a power outage occurs, this information is available for use by the emergency back-up power system.
The present invention provides AC power to the load through the stored energy of the storage medium during failure. The invention discloses a technology with which the reliability of the lift/ elevator operation is improved with no increase in cost. It simplifies the emergency operation or continued operation or temporary operation until the breakdown occurs. During mains failure, the backup system provides a backup for predefined time for emergency landing. During mains failure, lift goes in rescue mode. After completion of rescue mode the backup system's output is off.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a power source for backup to the lift/ elevator during power failure.
Another object of the present invention is to provide a power source for backup which monitors and stores the lift/ elevator operation.
Another object is to provide a lift/ elevator control system which is simple in construction and can readily be manufactured at a low cost.
Still another object of the present invention is to provide an efficient and intelligent power source for backup that saves stored energy.
Yet another object of the present invention is to provide a lift/ elevator control system which can detect various events by a single detecting element.
Yet another object of the present invention is to provide a power source for backup to the lift/ elevator which provides details of the lift/ elevator operations at a remote location.
Another object of the present invention is to provide a lift/ elevator control apparatus that permits energy saving by effectively utilizing electric power generated during a regenerative mode of an elevator.
Another object of the present invention is to provide a power backup system with automatic rescue mode operation as per user defined time configurations.
Still another object of the present invention is to provide a power backup system which operates with specified or selected time as per the requirement of the rescue mode operation.
Yet another objective of the present invention is to provide a power backup system which supplies the power as per user selected voltage and frequency configurations.
SUMMARY
According to this invention, there is provided a power backup1 system for a lift/ elevator during power failure. The invention provides AC power to the load through the stored energy of the storage medium during failure. The system comprises of rectifier section, controller, charger, AC-DC converter and an inverter section for generating the regulated AC output from the DC source, pulse width modulating generator and a DC-DC converter system supplying DC power supply to different sections & drivers. Further, the system has the provision for
charging the battery on par during low battery condition in the backup mode either through the available grid power or through a power generator.
In an aspect of the present invention, the invention is applicable for such as but not limited to the lift and elevator.
In an embodiment of the present invention, if the lift drive goes into fault condition, the backup system provides the power backup for emergency landing in any of the nearest floor.
In an embodiment of the present invention, the predefined time for emergency landing is 2minutes to 10 minutes.
STATEMENT OF INVENTION
According to this invention, there is provided an improved power backup system for lift/elevator comprises rectifier section and intelligent efficient charger module which charges the storage device, an inverter module which provides the voltage and frequency independent, efficient power during mains and in case of rescue mode also, controller of the total rescue mode operation setup which controls the power devices and is interfaced with the elevator control system wherein the controller logs the total elevator operation events through a single detecting device, a transfer device is provided which is excited by the load control apparatus in case of no mains is available and this transfers into back up mode for rescue operation to undergo, a regenerative energy converter to effectively harness the regenerative energy of the load, the secondary storage medium to deliver power during rescue mode wherein the load is connected between transfer device and the converter, remote monitoring unit and the graphical user interface to set up the parameters.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
Figure 1 shows the block diagram of the present invention.
Figure 2 shows the block diagram highlighting the unique features of the invention
Figure 3 shows the flow chart according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
Reference may be made to figure 1 and 2 which provides a power backup system for a lift/ elevator during power failure along with rescue operation. The invention provides AC power to the load through the stored energy of the storage medium during failure. The power backup system comprises rectifier section and intelligent efficient charger module which charges the storage device when the grid power or generator supply is available, an inverter module 2 which provides the voltage and frequency independent, efficient power during mains and in case of rescue mode also, the controller 3 of the total rescue mode operation setup which controls the power devices and gets interfaced with the elevator control system. The controller 3 logs the total elevator operation events through a single detecting device. There is an interface junction 4 where the present invention interfaces with the elevator control system. A transfer device 5 is provided which is excited by the elevator control apparatus in case of no mains and this transfers into back up mode for rescue operation to undergo. A regenerative energy converter 6 comprises an AC - DC converter which powers the storage medium using the energy released by the motor back EMF or regenerative energy. This
energy provides the voltage to the AC-DC converter, thereby the converter which is controlled by the main controller 3 charges the storage medium used to effectively harness the regenerative energy of the elevator motor. The secondary storage medium 7 delivers power during rescue mode. The elevator motor 8 is connected between transfer device 5 and the converter 6 which has been controlled effectively during rescue mode. The transfer device 5 is controlled by the interface unit. Transfer device 5 comprises of a contactor or a relay or a static switch which helps to transfer power from mains to inverter in case of no mains.
According to the present invention, during mains failure, the backup system provides a backup for predefined time for emergency landing. During mains failure, lift goes in rescue mode. After completion of rescue mode the backup system's output is off. Mains supply and inverter supply are connected to the contactor (here it is transfer device 5) in the lift. During mains failure, the contactor is transferred to the backup mode and provides the backup as per the programmed time for the landing of the lift at the nearest floor. After completion of the rescue mode the system is transferred to the mains mode again and do not provide any supply till the mains is available. If the power from mains is active within the specified backup time, the lift/ elevator waits for the next command till the inverter switches over to mains mode. As soon as the mains mode is active after the rescue mode, the lift goes to correction mode and reaches to the ground floor or any of the specified floors. During rescue mode, the system will not be transferred to the mains mode even if grid is ON. The predefined time is user settable and can be programmed as per the requirement.
Figure 2 shows the power backup unit with regenerative energy feature. The graphical user interface 9 is associated with the controller 3 through which user can access the controller 3 locally and set such as but not limited to the time of rescue operation, observe the number of elevator cycles, voltage, current, frequency, battery level with alarms and protections and faulty operation log. A remote monitoring device 10 is connected to the apparatus wired or wireless
through which we can log such as but not limited to all the elevator events, set the time of rescue operations, monitor all the parameters of the apparatus like battery level, voltage, command the system to transit the mode from ON-OFF or vice-versa.
In an aspect, if the battery of the backup system goes near to fewer limit and the lift/ elevator is on, the system automatically adjusts the lower voltage cutoff off point or depth of discharge of the batteries to run the lift/ elevator until it reaches a nearest floor. The present invention is provided with generator on command which in turn, turns on the generator automatically during low battery (during no grid power i.e. in backup mode) and charges the battery parallely. During no load, it maintains the battery in full charge state though it's charger takes the power from the generator/grid power.
The invention discloses a technology with which the reliability of the lift/ elevator operation is improved with no increase in cost. It simplifies the emergency operation or continued operation or temporary operation until the breakdown occurs.
Figure 3 shows the flow chart according to the present invention. The backup system calculates how many times a lift/ elevator has gone up and down at each floor. It generates the data of how long the lift stays on each floor. This is done by sensing the current flowing out of the transfer device 5 i.e. the current through the elevator motor. With the help of current, the upstream time, downstream time and the stalling time is detected. If the main is not present, the controller receives the signal from the elevator/ lift control system and the inverter is ON, the transfer device is operated and power is fed to the elevator through storage medium. The backup system checks if elevator/ lift is on the floor or stopped.at unsafe position. If it is stuck in an unsafe position, the system provides backup to the load until it reached to the nearest floor, the door opens till some preset time and no action will be performed till the mains is available. This time is accessible/configurable by the user. The load doesn't accept any inputs from user during rescue mode. It waits till the system goes into mains mode.
The power backup system provides the complete history of the lift operation. During power failure, the power backup system supplies the power with negligible switching time. The power backup system operates the lift till it reaches to the closest floor and waits till grid/generator power resumes for the next operation or works according to the operator's instructions. The backup system runs in backup mode for the time specified by the operator for time dependent on the power drawn by the lift. The present invention logs every position of lift and makes data retrievable as per the requirement.
The power backup system stores the above said details of the lift and the stored data is processed in a central database. The operator can access the data recorded at any time. The important parameters such as but not limited to input voltage, input frequency, output voltage, frequency, power, current, battery voltage, battery level, number of power cuts, how many time the lift was in each floor, total time of ups and downs, how many times the system breaks, faulty conditions & their duration can be monitored from a remote location. It is also possible to switch ON/ OFF the power backup system or lift from a remote location which makes the system safe. Also the output voltage, battery low level and load can be changed from a remote location. The system gives an alarm/ message to the operator during an emergency situation or faulty conditions.
Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

WE CLAIM:
1. An improved power backup system for a lift/elevator comprises rectifier section and intelligent efficient charger module which charges the storage device, an inverter module which provides the voltage and frequency independent, efficient power during mains and in case of rescue mode also, controller of the total rescue mode operation setup which controls the power devices and is interfaced with the elevator control system wherein the controller logs the total elevator operation events through a single detecting device, a transfer device is provided which is excited by the load control apparatus in case of no mains is available and this transfers into back up mode for rescue operation to undergo, a regenerative energy converter to effectively harness the regenerative energy of the load, the secondary storage medium to deliver power during rescue mode wherein the load is connected between transfer device and the converter, remote monitoring unit and the graphical user interface to set up the parameters.
2. An improved power backup system for lift/elevator as claimed in any of the preceding claims wherein the graphical user interface associated with the controller through which user accesses the controller and set such as but not limited to the time of rescue operation, observe the number of elevator cycles, voltage, current, frequency, battery level and faulty operation log.
3. An improved power backup system for lift/elevator as claimed in any of the preceding claims wherein the remote monitoring device is connected to the apparatus wired or wireless through which we can logging can be done such as but not limited to all the elevator events, set the time of' rescue operations, monitor all the parameters of the apparatus like battery level, voltage, command the system to transit the mode from ON-OFF or vice-versa.
4. An improved power backup system for lift/elevator as claimed in any of the preceding claims, wherein the mains and backup supply are connected to the contactor in the lift.
5. An improved power backup system for lift/elevator as claimed in any of the preceding claims, wherein, the predefined time for emergency landing is 2minutes to 10 minutes.
6. An improved power backup system for lift/elevator as claimed in any of the preceding claims, wherein in case mains is active within the specified backup time, the load waits for the next command till the inverter switches over to mains mode.
7. An improved power backup system for lift/elevator as claimed in any of the preceding claim, wherein the minimum and maximum time of backup supply can be set as per the requirement
8. An improved power backup system for lift/elevator as claimed in any of the preceding claims wherein if the mains mode is active after the rescue mode, the lift goes to correction mode and reaches to the ground floor or any of the specified floors.
9. An improved power backup system for a lift/elevator as claimed in any of the preceding claims wherein during rescue mode, the system is not transferred to the mains mode even if grid is ON.
10. An improved power backup system for a lift/elevator as claimed in any of the preceding claims wherein the load is lift or elevator.
11. An improved power backup system for a lift/elevator comprising of a generator such as herein described.
12. An improved power backup system for a lift/elevator as claimed in any of the preceding claims, wherein The transfer device is controlled by the interface unit in which the transfer device comprises of a contactor or a relay or a static switch which helps to transfer power from mains to inverter in case of no mains.
13. An improved power backup system for a lift/elevator as herein described
with reference to the accompanying drawings.