A DC charger and an electric vehicle short-circuit protection device, method and system

Abstract

A DC charger and electric vehicle short circuit protection device, method and system, characterized in that it includes a charger main controller CMU, an electric vehicle BMS and a protection device; the protection device is arranged between the charging gun and the DC input terminal, the charging gun is connected to the electric vehicle BMS, the electric vehicle BMS is connected to the charger main controller CMU, and the charger main controller CMU is connected to the protection device. The present invention gives full play to the fuse protection function of the charger, improves the safety protection of the charger and the electric vehicle during charging, and reduces the maintenance cost of the electric vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and in particular relates to a direct current charger and an electric vehicle short-circuit protection device, method and system. Background Art

[0002] With the development of electric vehicle technology, there are more and more electric vehicle manufacturers and more and more types of electric vehicles. The parameters of various electric vehicle models vary greatly. The most important parameter is the charging current of the electric vehicle. The maximum charging current of each model is different. The difference in charging current leads to different specifications of the corresponding short-circuit protection fuse inside the electric vehicle.

[0003] The national standard for DC chargers also stipulates the current of the charging gun, which is divided into: 80A, 125A, 200A, and 250A.

[0004] Since the charger uses a charging gun with a fixed current specification, the fuse specification corresponding to the charger protection is also basically determined, that is, the fuse rated current = charging gun current value * k (coefficient k>1). At present, the mainstream charging gun specification on the charger market is 250A. The charger manufacturer selects the corresponding short-circuit protection fuse according to the current specification of the charging gun. The fuse rated current = 250A*k.

[0005] However, the actual maximum charging current of electric vehicles in the market can reach 250A. Therefore, when designing electric vehicles, the rated current of the internal short-circuit protection fuse is generally less than 250A or less than the rated current of the internal fuse of the charger corresponding to the 250A charging gun of the charger (250A*k). The problem caused by this is that when a short circuit occurs in the market, the probability of the fuse inside the charger being activated is almost zero, while the fuse inside the electric vehicle is likely to be blown every time.

[0006] At present, there are no effective measures and technical research on the matching of fuses for chargers and electric vehicle charging short-circuit protection in the market. Because the maximum current referenced by the two fuses is inconsistent, it is easy to cause the internal fuse of the electric vehicle to blow every time, and the maintenance cost of replacing the electric vehicle fuse when it fails is quite high. Summary of the invention

[0007] The object of the present invention is to provide a DC charger and an electric vehicle short-circuit protection device, method and system to solve the above problems.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A DC charger and an electric vehicle short-circuit protection device, comprising a charger main controller CMU, an electric vehicle BMS and a protection device; the protection device is arranged between a charging gun and a DC input terminal, the charging gun is connected to the electric vehicle BMS, the electric vehicle BMS is connected to the charger main controller CMU, and the charger main controller CMU is connected to the protection device.

[0010] Furthermore, the protection device includes a plurality of fuses and a plurality of contactors; the plurality of contactors form a contactor array, the plurality of fuses form a fuse array, and each contactor is connected in series with a corresponding fuse.

[0011] Furthermore, the DC input terminal is connected to the contactor array, and the fuse array is connected to the charging gun via the main contactor.

[0012] Furthermore, the protection device also includes a controller, and the controller is connected to the contactor array.

[0013] Furthermore, the charger main controller CMU is connected to the controller.

[0014] Furthermore, a protection method for a DC charger and an electric vehicle short-circuit protection device comprises the following steps:

[0015] Before starting charging, the charger's main controller CMU and the electric vehicle's BMS first conduct a handshake communication. After the handshake is successful, normal communication is established and relevant information is obtained from each other. The battery information uploaded to the CMU by the BMS includes the maximum charging current and the maximum allowable charging current of the battery. After obtaining the maximum allowable charging current of the BMS, the CMU records it.

[0016] After the entire communication interaction between CMU and BMS is completed, CMU calculates and compares the maximum allowable charging current of BMS and the rated currents of fuses F1, F2...FN corresponding to K1, K2...KN. Then CMU communicates with the controller of the protection device and selects a fuse with a suitable current specification by closing a certain contactor.

[0017] Through the above actions, the selection of the fuse that matches the current charging current of the electric vehicle is completed. After one of the contactors K1, K2...KN is energized, the CMU controls the charger to perform self-test and insulation test until it enters the charging state.

[0018] After charging is completed, the charger turns off the charging module, disconnects the main contactor Kz, and then disconnects the previously closed contactor K1, K2...KN at the front end of the fuse; after completing the entire action, it enters the standby state and waits for the next charging cycle to start.

[0019] Furthermore, the calculation and comparison specifically include:

[0020]

[0021] Where: I_FN represents the rated current of a fuse;

[0022] I_BMS represents the maximum allowable charging current of the electric vehicle BMS;

[0023] According to the above calculation method, CMU can select the appropriate KN and the corresponding FN for a specific electric vehicle, thereby closing the selected KN and putting the FN into the protection circuit.

[0024] Furthermore, a DC charger and an electric vehicle short circuit protection system include:

[0025] The communication establishment module is used for handshake communication between the main controller CMU of the charger and the BMS of the electric vehicle before starting charging. After the handshake is successful, normal communication is established to obtain relevant information from each other. The battery information uploaded to the CMU by the BMS includes the maximum charging current and the maximum allowable charging current of the battery. After obtaining the maximum allowable charging current of the BMS, the CMU records it.

[0026] The calculation and comparison module is used for the entire communication interaction between CMU and BMS. After the CMU is completed, it calculates and compares the maximum allowable charging current of BMS and the rated current of fuses F1, F2...FN corresponding to K1, K2...KN. Then, CMU communicates with the controller of the protection device and selects a fuse with a suitable current specification by closing a certain contactor.

[0027] Through the above actions, the selection of the fuse that matches the current charging current of the electric vehicle is completed. After one of the contactors K1, K2...KN is energized, the CMU controls the charger to perform self-test and insulation test until it enters the charging state.

[0028] The standby preparation module is used to disconnect the main contactor Kz after the charging is completed. Then, the previously closed contactor among the contactors K1, K2...KN at the front end of the fuse is disconnected. After completing the whole action, it enters the standby state and waits for the next charging cycle to start.

[0029] Compared with the prior art, the present invention has the following technical effects:

[0030] The basic principle of the present invention is that the existing charging piles only have fixed fuses, and their specifications are selected according to the rated current of the charging gun. The actual maximum charging current of electric vehicles is less than the rated current of the charging gun. In this way, when a short circuit occurs, the fuse in the car will often blow, and the fuse of the charging pile is too large, resulting in protection failure. The relationship is as follows:

[0031] I_BMS <I_fuse_ev<I_fuse_charger / k1

[0032] Where: I_BMS maximum allowable charging current for electric vehicles

[0033] I_fuse_ev Electric vehicle fuse rated current

[0034] I_fuse_charger Charging pile fuse rated current

[0035] k1 proportionality coefficient, k1>1

[0036] The present invention increases the flexibility of fuse adaptation through automatic calculation of the charging pile and selection of KN-FN, so that electric vehicles with different charging currents can be adapted to suitable protective fuses, and the fuses can be blown in time when a short circuit occurs during the charging process by utilizing the overload and short-circuit protection characteristics of the fuses, thereby protecting the electric vehicles from damage.

[0037] The relationship is as follows:

[0038] I_BMS <I_fuse_charger≤I_fuse_ev

[0039] Where: I_BMS maximum allowable charging current for electric vehicles

[0040] I_fuse_ev Electric vehicle fuse rated current

[0041] I_fuse_charger Charging pile fuse rated current

[0042] k1 proportionality coefficient, k1>1

[0043] The present invention can maximize the protective effect of the internal fuse of the charger, and avoid the fuse inside the high-power charger on the market becoming a decoration. Every time a charging short circuit fault occurs, the fuse inside the electric vehicle is activated to provide protection. Moreover, when the fuse of the electric vehicle fails, other components may also be burned. At the same time, the maintenance cost is very high.

[0044] The present invention gives full play to the protective function of the fuse of the charger, improves the safety protection of the charger and the electric vehicle during the charging process, and reduces the maintenance cost of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the schematic diagram of the short-circuit protection device inside the charger. DETAILED DESCRIPTION

[0046] The present invention is further described below in conjunction with the accompanying drawings:

[0047] See also Figure 1 The protection device is selected and installed according to the fuse industry specifications and the common specifications of electric vehicles. The rated currents of the fuse arrays F1, F2...FN are I1, I2...IN from small to large. The current specifications of the contactor arrays K1, K2...KN are selected according to the fuse current specifications. Kz is the main contactor, and its specifications are selected according to the charging gun current.

[0048] Before starting charging, the main controller CMU of the charger and the BMS of the electric vehicle first conduct a handshake communication. After the handshake is successful, normal communication is established and relevant information is obtained from each other. The battery information uploaded to the CMU by the BMS includes the maximum charging current and the maximum allowable charging current of the battery. After obtaining the maximum allowable charging current of the BMS, the CMU records it. After the entire communication interaction between the CMU and the BMS is completed, the CMU calculates and compares the maximum allowable charging current of the BMS and the rated current of the fuses F1, F2...FN corresponding to K1, K2...KN, and then the CMU communicates with the controller of the protection device and selects a fuse of appropriate specification current by closing a certain contactor. Through the above actions, the selection of the fuse that matches the current charging current of the electric vehicle is completed, which can fully play the role of short-circuit protection.

[0049] After one of the contactors K1, K2, ...KN is energized, the CMU controls the charger to perform self-test and insulation test until it enters the charging state.

[0050] After charging is completed, the charger turns off the charging module, disconnects the main contactor Kz, and then disconnects the previously closed contactor K1, K2...KN at the front end of the fuse. After completing the entire action, it enters the standby state and waits for the next charging cycle to start.

[0051] Example:

[0052] A DC charger and an electric vehicle short-circuit protection device, comprising a charger main controller CMU, an electric vehicle BMS and a protection device; the protection device is arranged between a charging gun and a DC input terminal, the charging gun is connected to the electric vehicle BMS, the electric vehicle BMS is connected to the charger main controller CMU, and the charger main controller CMU is connected to the protection device.

[0053] The protection device comprises 10 fuses and 10 contactors; the 10 contactors form a contactor array, the 10 fuses form a fuse array, and each contactor is connected in series with a corresponding fuse.

[0054] The DC input terminal is connected to the contactor array, and the fuse array is connected to the charging gun through the main contactor.

[0055] The protection device also includes a controller, which is connected to the contactor array.

[0056] The charger main controller CMU is connected to the controller.

[0057] A protection method for a DC charger and an electric vehicle short-circuit protection device, comprising the following steps:

[0058] Before starting charging, the charger's main controller CMU and the electric vehicle's BMS first conduct a handshake communication. After the handshake is successful, normal communication is established and relevant information is obtained from each other. The battery information uploaded to the CMU by the BMS includes the maximum charging current and the maximum allowable charging current of the battery. After obtaining the maximum allowable charging current of the BMS, the CMU records it.

[0059] After the entire communication interaction between CMU and BMS is completed, CMU calculates and compares the maximum allowable charging current of BMS and the rated currents of fuses F1, F2...FN corresponding to K1, K2...KN. Then CMU communicates with the controller of the protection device and selects a fuse with a suitable current specification by closing a certain contactor.

[0060] The calculation and comparison specifically include:

[0061]

[0062] Where: I_FN represents the rated current of a fuse;

[0063] I_BMS represents the maximum allowable charging current of the electric vehicle BMS;

[0064] According to the above calculation method, CMU can select the appropriate KN and the corresponding FN for a specific electric vehicle, thereby closing the selected KN and putting the FN into the protection circuit.

[0065] Through the above actions, the selection of the fuse that matches the current charging current of the electric vehicle is completed. After one of the contactors K1, K2...KN is energized, the CMU controls the charger to perform self-test and insulation test until it enters the charging state.

[0066] After charging is completed, the charger turns off the charging module, disconnects the main contactor Kz, and then disconnects the previously closed contactor K1, K2...KN at the front end of the fuse. After completing the entire action, it enters the standby state and waits for the next charging cycle to start.

Claims

1. A protection method for a DC charger and an electric vehicle short-circuit protection device, characterized in that: A DC charger and an electric vehicle short-circuit protection device, comprising a charger main controller CMU, an electric vehicle BMS and a protection device; the protection device is arranged between a charging gun and a DC input terminal, the charging gun is connected to the electric vehicle BMS, the electric vehicle BMS is connected to the charger main controller CMU, and the charger main controller CMU is connected to the protection device; The protection device includes a plurality of fuses and a plurality of contactors; the plurality of contactors form a contactor array, the plurality of fuses form a fuse array, and each contactor corresponds to a fuse connected in series; The DC input terminal is connected to the contactor array, and the fuse array is connected to the charging gun through the main contactor; The protection device also includes a controller connected to the contactor array; The charger main controller CMU is connected to the controller; The method comprises the following steps: Before starting charging, the charger's main controller CMU and the electric vehicle's BMS first conduct a handshake communication. After the handshake is successful, normal communication is established and relevant information is obtained from each other. The battery information uploaded to the CMU by the BMS includes the maximum charging current and the maximum allowable charging current of the battery. After obtaining the maximum allowable charging current of the BMS, the CMU records it. After the entire communication interaction between CMU and BMS is completed, CMU calculates and compares the maximum allowable charging current of BMS and the rated currents of fuses F1, F2...FN corresponding to K1, K2...KN. Then CMU communicates with the controller of the protection device and selects a fuse with a suitable current specification by closing a certain contactor. Through the above actions, the selection of the fuse that matches the current charging current of the electric vehicle is completed. After one of the contactors K1, K2...KN is energized, the CMU controls the charger to perform self-test and insulation test until it enters the charging state. After charging is completed, the charger turns off the charging module, disconnects the main contactor Kz, and then disconnects the previously closed contactor K1, K2...KN at the front end of the fuse; after completing the entire action, it enters the standby state and waits for the next charging cycle to start.

2. A protection method for a DC charger and an electric vehicle short-circuit protection device according to claim 1, characterized in that: The calculation and comparison specifically include: Where: I_FN represents the rated current of a fuse; I_BMS represents the maximum allowable charging current of the electric vehicle BMS; According to the above calculation method, CMU can select the appropriate KN and the corresponding FN for a specific electric vehicle, thereby closing the selected KN and putting the FN into the protection circuit.

3. A DC charger and an electric vehicle short circuit protection system, characterized in that: include: The communication establishment module is used for handshake communication between the main controller CMU of the charger and the BMS of the electric vehicle before starting charging. After the handshake is successful, normal communication is established to obtain relevant information from each other. The battery information uploaded by the BMS to the CMU includes the maximum charging current and the maximum allowable charging current of the battery. After obtaining the maximum allowable charging current from the BMS, the CMU records it. The calculation and comparison module is used for the entire communication interaction between CMU and BMS. After the CMU is completed, it calculates and compares the maximum allowable charging current of BMS and the rated current of fuses F1, F2...FN corresponding to K1, K2...KN. Then, CMU communicates with the controller of the protection device and selects a fuse with a suitable current specification by closing a certain contactor. Through the above actions, the selection of the fuse that matches the current charging current of the electric vehicle is completed. After one of the contactors K1, K2...KN is energized, the CMU controls the charger to perform self-test and insulation test until it enters the charging state. The standby preparation module is used to disconnect the main contactor Kz after the charging is completed. Then, the previously closed contactor among the contactors K1, K2...KN at the front end of the fuse is disconnected. After completing the whole action, it enters the standby state and waits for the next charging cycle to start.

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