Description:FIELD OF INVENTION
Embodiments of a present disclosure relate to a charging system, particularly an Encapsulated charger with a provision for Dielectric Withstand Voltage testing and Surge testing.
BACKGROUND
The use of Electric vehicles in the modern era is inevitable. The electric vehicles are powered with battery packs which are essentially helping in powering the vehicle’s motor unit as well as auxiliary power systems.
In conventional electrical chargers there exists internal electrical gaps and insulation of the electrical equipment in the Printed Circuit Board (PCB) which is sufficient to safeguard the electric vehicle from any electrical leakage that eventually protects a user from shock.
The dielectric withstand voltage test of the electrical chargers comprising of the internal gaps and insulation layer is a test used to ensure that under very severe over voltage conditions, the encapsulation and other insulation materials within the charger is sufficient to prevent electric shock to the user and thereby ensures a safe normal operation of electric vehicles. These dielectric withstand voltage tests enable users to avoid catching electrical shocks whilst operating the electric vehicles and also provide protection to other important sensitive electrical components like batteries, and motors.
In the conventional electric chargers, there is a need for a dielectric withstand voltage test and as for the dielectric withstand voltage test, the test voltage is provided between the earth and a shorted junction comprising positive and neutral input points of the charger short-circuited. In such instances when a high amount of voltage is applied to test the dielectric strength of the insulated charger some of the critically sensitive electrical components like spark gap specifically a Gas discharge tube (GDT) blow up due to the flow of a high amount of current through it. This eventually damages the associated sensitive electrical components thereby creating short circuits in the printed circuit board and attached electrical components.
To overcome the problem, the spark gap is kept disconnected during the dielectric withstand voltage test. Subsequently, once the test is executed then the spark gap is again connected back to the circuit.
PROBLEM TO BE SOLVED BY INVENTION
In such instances, where the electrical chargers are encapsulated with a potting material, the connection/disconnection of the spark gap or any mechanical operation of the spark gap becomes hard for the user. It becomes difficult for the user to perform the dielectric withstand voltage test on an encapsulated charger. Therefore, the primary objective of the present invention is to provide an encapsulated charger wherein the dielectric withstand voltage test can be easily conducted without damaging of any electrical components.
Conventional electric chargers offer limited insulation and eventually may fail at higher voltage applications where the efficiency of the charger is poor. These chargers could offer the possibility of poor insulation or no insulation and damage the circuit when the high voltage applications where voltage difference is applied and finally damaging the entire circuit due to poor insulation. Thus, another objective of the present invention is to provide an encapsulated charger whose dielectric strength can be easily tested anytime during the lifespan of the encapsulated charger once it is manufactured
As discussed earlier, a blow-up of the spark gap may result in damage to other nearby electrical components and may result in the complete replacement of the charger. Thus, another objective of the present invention is to provide an encapsulated charger wherein the blow-up of the spark gap is inevitable when a high amount of voltage is applied to the charging circuitry.
BRIEF DESCRIPTION OF THE INVENTION
In the present disclosure, the encapsulated charger of an electric vehicle has a provision to test the dielectric strength. The encapsulated charger comprises an electrical module, a protection unit, an encapsulated layer, a spark gap, and a detachable conductor. The electrical module comprises of two or more input power lines to be connected to a DC power source. The Protection circuit is configured to protect the electrical module from common mode surges generated on the input power lines connected to the DC power source. The protection unit comprises a spark gap which is configured to limit the voltage surges. The spark gap is set to limit such fluctuating surges. A rivet is configured to couple with the spark gap in order to conduct an electrical transmission along with the spark gap. Moreover, a housing assembly is configured to hold the electrical module intact and the housing assembly is connected to a protective earthing that includes an opening in line with the rivet of the spark gap. The encapsulated charger further comprises an encapsulated layer that enables insulation between the housing assembly and the electrical module. The detachable conductor is configured to be fastened with the rivet coupled to the spark gap through the opening of the housing assembly and the encapsulated layer. Thereafter, before starting the dielectric strength testing of the encapsulated charger the detachable conductor is unfastened from the rivet coupled to the spark gap to disconnect the electrical connection between the spark gap and the housing assembly protecting the spark gap from damage.
As per the first embodiment, the detachable conductor of the encapsulated charger is a conducting screw.
As per the second embodiment, the housing assembly is coupled with a frame of the electric vehicle.
As per the third embodiment, the encapsulated layer is composed of a potting compound.
As per the fourth embodiment, the electrical module of the encapsulated charger is a Printed circuit board (PCB) module. The printed circuit board may comprise a protection circuit or safety circuit that can operate in a fail-safe environment
As per the fifth embodiment, the protection circuit comprises of one or more metal oxide varistors (MOVs).
As per the sixth embodiment, the spark gap of the encapsulated charger is a Gas Discharge Tube (GDT). These gas discharge tubes work for limiting the voltage and energy dispersion and make the apparatus get protected and withstand lightning surges.
LIST OF FIGURES
The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
Figure 1 is a schematic representation of the circuit connection of Encapsulated Charger for charging battery cells in a battery pack in accordance with an embodiment of the present disclosure.
Figure 2 is a schematic representation of the encapsulated charger with dielectric withstand test setup in accordance with another embodiment of the present disclosure; and
Figure 3 is a schematic representation of the encapsulated charger for charging the battery pack with provision for surge protection generated from a surge generator in accordance with another embodiment of the present disclosure.
Figure 4 is a schematic representation of a side view of the electric vehicle representing a Charger connection with a frame in accordance with an embodiment of the present disclosure.
Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION OF THE INVENTION
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as would normally occur to those skilled in the art are to be construed as being within the scope of the present invention.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
The terms “comprises”, "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or subsystems or elements or structures or components preceded by "comprises... a'' does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
Embodiments of the present invention will be described below in detail with reference to the accompanying figures.
An encapsulated charger (101) of an electric vehicle (10) with dielectric strength testing provision, the encapsulated charger (101) comprises an electrical module (1011), the electric module (1011) comprises two or more input power lines (1012) to be connected to a DC power source (1013). The encapsulated charger (101) also comprises a Surge protection circuit (1014) that enables protection against short circuits. The Surge protection circuit (1014) is configured to protect the electrical module (1011) from common mode surges generated on input power lines (1012). The common mode surges are due to lightning surges on the Input power lines. The Surge protection circuit (1014) comprises, a Spark gap (1015) configured to limit voltage surges and a Rivet (1016) coupled to the spark gap (1015). The rivet (1016) is configured such that the rivet (1016) remains electrically connected to the spark gap (1015) and carries out electrical transmission with the spark gap (1015). Moreover, the encapsulated charger (101) comprises a housing assembly (1017) configured to hold the electrical module (1011) and said housing assembly (1017) is connected to a protective earthing (1018). The housing assembly (1017) includes an opening (1025) in line with the rivet (1016) of the spark gap (1015). Again, the encapsulated charger (101) includes an encapsulated layer (1019) configured to provide insulation between the electrical module (1011) and the housing assembly (1017). Further, a detachable conductor (1020) is configured to be fastened with the rivet (1016) coupled to the spark gap (1015) through the opening (1025) of the housing assembly (1017) and the encapsulated layer (1019). Furthermore, before starting the dielectric strength testing of the encapsulated charger (101) the detachable conductor (1020) is unfastened from the rivet (1016) coupled to the spark gap (1015) to disconnect the electrical connection between the spark gap (1015) and the housing assembly (1017) protecting the spark gap (1015) from damage.
FIG. 1 is a schematic representation of an Encapsulated Charger (101) with dielectric testing provision in accordance with an embodiment of the present disclosure. The figure illustrates the connection of the circuit of the encapsulated charger (101) under normal or standard conditions, i.e. when the encapsulated charger (101) is in charging condition. Figure 1 illustrates an Alternating current (AC) power source (1013) connected to input power lines (1012) of the encapsulated charger (101). Two metal oxide varistors (MOVs) (1021) of the Surge protection circuit (1014) connected in series with each other are connected to the input power lines (1012) wherein the MOVs (1021) are in parallel connection with the AC power source (1013). Subsequently, the spark gap (1015) is connected with the MOVs (1021) and the rivet (1016). As illustrated, the rivet (1016) and the housing assembly (1017) are connected with a detachable conductor (1020), and eventually, the housing assembly (1017) is connected with a protective earthing (1018). In any instance when a surge is applied to the input power lines (1012) of the encapsulated charger (101) that may take place by lightening surge on the AC Power Line, the surge may be applied either in between the positive to the protective earth terminal or in between the neutral power line and the protective earthing (1018). During such surges, a high amount of current flows through the circuit. As the MOVs (1021) are in a parallel connection with the input lines, the resistance value of the MOVs (1021) decreases, and the MOVs (1021) act as a short-circuited path between the positive and protective earthing (1018) or between the neutral power line and protective earthing (1018) as per the instance. As a result, the high amount of current is easily transmitted, and the charging circuitry remains protected. On the other hand, as the duration of lightning surges are for a very short time such as 15-20 microseconds, the spark gap (1015) sustains and withstands the high amount of current for such a short duration and the high amount of current is earthed through the protective earthing (1018).
Figure 2 is a schematic representation of the encapsulated charger (101) with dielectric withstand voltage test setup in accordance with another embodiment of the present disclosure. The figure illustrates the connection of the circuit wherein the encapsulated charger (101) undergoes a dielectric withstand voltage test or a dielectric strength test. In order to perform the test, the input power lines (1012) are short-circuited by a short circuit cable (11022), i.e. the positive and neutral terminal of the encapsulated charger (101) is short-circuited and a high-voltage DC source (1023) is connected to the short-circuit cable (1022) and the protective earthing (1018). On the other hand, the detachable conductor (1020) connecting the housing assembly (1017) and the Spark gap (1015) through the rivet (1016) is unscrewed. As a result, the spark gap (1015) gets electrically disconnected from the protective earthing (1018) and also from a frame (103) of the electric vehicle (10). Eventually, on the application of high voltage DC input, the spark gap (1015) remains unaffected irrespective of the duration of the high voltage DC input provided to the encapsulated charger (101). Thus, the dielectric withstands voltage test of the encapsulated charger (101) is performed adequately.
Figure 3 illustrates a schematic representation of the encapsulated charger (101) in accordance with another embodiment of the present invention. The schematic representation illustrates the circuit diagram of the encapsulated charger (101) in the event of testing the encapsulated charger (101) with a generated surge. A surge generator (1024) is connected to the input power lines (1012) of the encapsulated charger (101) to include a surge with the power provided by the AC power source (1013). On the other hand, the detachable conductor (1020) is fitted to connect the rivet (1016) with the housing assembly (1017) and eventually, establishes an electrical connection between the spark gap (1015) and the protective earthing (1018). In such instances, in the occurrence of a surge generated from a surge generator (1024) the resistance value of the MOVs (1021) decreases and provides a short-circuited path between the positive and neutral power line. Moreover, due to the short time duration of the surge, the spark gap (1015) withstands the surge and the generated surge is earthed through the protective earthing (1018).
Figure 4 illustrates a side view of the electric vehicle (10) disclosing the encapsulated charger (101) connected to the frame (103) of the electric vehicle (10) in accordance with another embodiment of the present invention. The housing assembly (1017) of the encapsulated charger (101) is connected to the frame (103) of the electric vehicle (10) with the detachable conductor (1020). The frame (103) of the electric vehicle (10) provides a protective earthing (1018) to the encapsulated charger (101).
As per the first embodiment of the present invention, the detachable conductor (1020) of the encapsulated charger (101) is a conducting screw. The conducting screw may have a connecting shaft and nut and screw head which helps in connection. Moreover, the length of the detachable conductor (1020) is predetermined so that it tightly gets fixed with the opening (1025) present on the housing assembly (1017) and ensures good electrical conductivity between the rivet (1016) and the housing assembly (1017). Further, the detachable conductor (1020) may further include a rubber ring that gets compressed when the detachable conductor (1020) is screwed and eventually restricts the entry of water or similar liquids from entering inside the encapsulated charger (101).
As per the second embodiment of the present invention, the housing assembly (1017) of the encapsulated charger (101) is connected to the frame (103) of the electric vehicle (10). The frame (103) may be the main frame (103) of the electric vehicle (10). In an exemplary embodiment, the housing assembly (1017) is sandwiched between the rivet (1016) and the frame (103) connected through the detachable conductor (1020).
As per the third embodiment of the present invention, the encapsulated layer (1019) of the encapsulated charger (101) is composed of a potting compound. The potting compound has fast curable properties and provides high electric insulation. The potting compound provides a waterproof and dustproof layer across the electrical module (1011).
As per the fourth embodiment of the present invention, the electrical module (1011) of the encapsulated charger (101) is a Printed circuit board (PCB) module. The printed circuit board may comprise a power factor correction (PFC) section, a DC-DC converter, and a Supervisory microcontroller. Moreover, the PFC section may further include Electromagnetic Interference (EMI) filters and the Surge protection circuit (1014).
As per the fifth embodiment of the present invention, the Surge protection circuit (1014) of the encapsulated charger (101) comprises one or more metal oxide varistors (MOVs) (1021). The metal oxide varistors come in form of voltage clamping devices where there is a need for short and voltage dependant varistors at a wider range of voltage and currents. In transient conditions, these MOVs (1021) are faster and slower in normal operations.
As per the sixth embodiment of the present invention, the spark gap (1015) of the encapsulated charger (101) is a Gas Discharge Tube (GDT). These gas discharge tubes work for limiting the voltage and energy dispersion and make the apparatus get protected and withstand lightning surges due to its short duration of existence.
FURTHER ADVANTAGES OF INVENTION
So, the current invention solves the problem of providing an encapsulated charger (101) wherein the dielectric withstand voltage test can be easily conducted without damaging any electrical components. As per the disclosure, the spark gap (1015) connected to the Surge protection circuit (1014) can be easily connected and disconnected from the protective earthing (1018) as per the requirement. As a result, the qualified tested encapsulated charger (101) provide excellent dielectric strength and withstands high voltage test, and protects the other electrical modules, components, and even the user from the shock upon short-circuit or exposure to high fluctuating electrical loads.
The solution as provided by the present invention also provides a provision in an encapsulated charger (101) whose dielectric strength can be easily tested anytime during the lifespan of the encapsulated charger (101) once it is manufactured. The provision provided in the encapsulated charger (101) protects the spark gap (1015) against high voltage by unscrewing the detachable conductor (1020) and thereby the high amount of current doesn’t damage the battery pack or attached electrical modules. Internal components which are attached along with the spark gap (1015) are protected when the voltage or electric fluctuations cause the blowing of the spark gap (1015) and damage the circuit as the spark gap (1015) remains protected from blowing off during the dielectric withstand voltage test.
The encapsulated charger (101) has good wear resistance and the deployment of potting fluid makes the encapsulated layer (1019) protects against all thermal or electrical shocks while testing.
The encapsulated charger (101) as disclosed in the present invention may be energy efficient and also operates in transient conditions since the spark gap (1015) withstands the transient conditions.
The present invention protects the users from getting shocks when encapsulated charger (101) are exposed to high voltage fluctuations during testing since the electrical resistance, and dielectric strength of the present encapsulated charger (101) is high.
 
REFERENCE LIST:

S. No. Name Reference Numerals
1 Electric Vehicle 10
2 Encapsulated Charger 101
3 Electrical Module 1011
4 Input Power Lines 1012
5 AC Power Source 1013
6 Surge Protection Circuit 1014
7 Spark Gap 1015
8 Rivet 1016
9 Housing Assembly 1017
10 Protective Earthing 1018
11 Encapsulated Layer 1019
12 Detachable Conductor 1020
13 Metal Oxide Varistor (MOV) 1021
14 Short circuit cable 1022
15 High Voltage Dc Source 1023
16 Surge Generator 1024
17 Opening 1025
18 Frame 103

 
, Claims:CLAIMS:

We claim
1. An encapsulated charger (101) of an electric vehicle (10) with dielectric strength testing provision, the encapsulated charger (101) comprises:
an electrical module (1011), the electric module (1011) comprises,
two or more input power lines (1012) to be connected to a DC power source (1023),
a Surge protection circuit (1014) configured to protect the electrical module (1011) from common mode surges generated on the input power lines (1012),
the Surge protection circuit (1014) comprises,
a Spark gap (1015) configured to limit voltage surges,
a Rivet (1016) coupled to the spark gap (1015), the rivet (1016) configured to carry out electrical transmission with the spark gap (1015),
a housing assembly (1017) configured to hold the electric module (1011), said housing assembly (1017) connected to a protective earthing (1018) includes an opening (1025) in line with the rivet (1016) of the spark gap (1015),
an encapsulated layer (1019) configured to provide insulation between the electric module (1011) and the housing assembly (1017),
a detachable conductor (1020) configured to be fastened with the rivet (1016) coupled to the spark gap (1015) through the opening (1025) of the housing assembly (1017) and the encapsulated layer (1019),
wherein
before starting the dielectric strength testing of the encapsulated charger
the detachable conductor (1020) is unfastened from the rivet (1016) coupled to the spark gap (1015) to disconnect the electrical connection between the spark gap (1015) and the housing assembly (1017) protecting the spark gap (1015) from damage.
2. The encapsulated charger (101) as claimed in claim 1, wherein the detachable conductor (1020) is a conducting screw.
3. The encapsulated charger (103) as claimed in claim 1, wherein the housing assembly (1017) is coupled with a frame (103) of the electric vehicle (10).
4. The encapsulated charger (103) as claimed in claim 1, wherein the encapsulated layer (1019) is composed of a potting compound.
5. The encapsulated charger (103) as claimed in claim 1, wherein the electrical module (1011) is a Printed circuit board (PCB) module.
6. The encapsulated charger (103) as claimed in claim 1, wherein the Surge protection circuit (1014) comprises one or more metal oxide varistors (MOVs) (1021).
7. The encapsulated charger (101) as claimed in claim 1, wherein the spark gap (1015) is a Gas Discharge Tube (GDT).