A power supply system and control method for an electrically powered chiller and applications

Abstract

The application belongs to the technical field of new energy electric vehicle power supply control, and particularly relates to an electric refrigerator power supply system, a control method and application, which comprises a power-on control circuit, a power-off control circuit and an abnormal power-off circuit, and the above circuits comprise a control console, a power battery, a wake-up signal module, an auxiliary power supply, a DC-DC, a compressor, a CPU, a pre-charge circuit, a bus capacitor, a first relay, a second relay, a third relay, a fourth relay, a monostable trigger, a first delay circuit, a second delay circuit and a third delay circuit, wherein the second relay is a vacuum relay, and the first relay, the third relay and the fourth relay are all ordinary relays. The application not only solves the high cost and weight burden of using multiple large-current vacuum relays in the traditional scheme, improves the economic efficiency and lightweight level of the system, but also reduces the overall assembly difficulty and the later maintenance cost of the circuit, and improves the market competitiveness of the product.

Description

Technical Field

[0001] This invention belongs to the technical field of new energy power supply control, specifically relating to an electric chiller power supply system and control method and its application in thermal management units for new energy electric vehicles or battery energy storage. Background Technology

[0002] As a core component of cold chain transportation, the electric refrigeration unit of an electric refrigerated truck is directly connected to the vehicle's power battery. In order to meet the energy replenishment needs, it also needs to be compatible with the mains power input mode. When the mains power is input, the refrigeration unit must be physically disconnected from the power battery. Therefore, the power-on and power-off control circuits and strategies of the refrigeration unit are crucial to the system's reliability, safety and operating costs.

[0003] Currently, the mainstream power supply control schemes for electric chillers in the industry generally install vacuum relays (such as...) at the positive and negative busbars of the chiller and battery pack. Figure 2 As shown in the diagram, the refrigeration unit controller on the control panel directly outputs a 27V wake-up voltage to the relay coil to control the connection and disconnection of the refrigeration unit and the power battery. When switching between refrigeration unit under load (such as when the compressor or DC-DC converter is operating), this solution requires a high-current vacuum relay (typically 50-100A) capable of breaking under load to prevent contact sticking. However, while vacuum relays have the ability to break under load, they are large, heavy, and expensive, and their lifespan is closely related to the switching current. Switching under load accelerates contact aging and affects the overall reliability of the system. Furthermore, this solution relies solely on the wake-up voltage output by the controller to directly control the relay's on / off state, lacking redundant logic for both software and hardware control. When the refrigeration unit's internal CPU crashes or the program malfunctions, the CAN communication between the controller and the unit is interrupted, preventing orderly power-down. This can easily lead to instantaneous high currents in various components due to abnormal power loss, damaging core components such as the DC-DC converter and compressor. It can also cause secondary damage due to non-zero current or zero voltage switching of the relay.

[0004] Existing technologies have addressed the aforementioned problems. For example, patent document CN118991432A – Vehicle Power-On Circuit, Control Method, and Vehicle – utilizes the bidirectional energy flow characteristics of an integrated OBC (On-Board Charger) and DCDC (Direct-to-DC Converter) module, eliminating the need for pre-charge relays and pre-charge resistors to reduce costs and save space. However, this solution primarily focuses on the overall vehicle power-on and power-off management and does not specifically address the isolation between mains power and battery power in the refrigeration system, or reliable power-off protection under special conditions such as CPU malfunctions. Furthermore, patent document CN110971175A – A High-Voltage Power-On Circuit, Control Method, and Servo Driver – uses a control switching circuit to reuse a resistor, acting as a current-limiting resistor during charging and a braking resistor during braking. While this solution achieves component reuse in the servo driver field, its application scenarios and technical concepts differ significantly from the power-on and power-off control required for electric refrigerated truck refrigeration units, which involves multi-power supply isolation and multiple safety protection mechanisms. Patent document CN118040824A describes a method, system, and circuit for controlling the power-on and power-off of a battery management system (BMS). This method intelligently manages the power-on and power-off process by detecting battery levels and other conditions to prevent over-discharge. However, this solution focuses on battery management strategies and does not delve into multi-relay collaborative control on the cold load side or the design of hardware-level protection circuits for CPU failure.

[0005] In summary, although existing technologies have proposed optimization strategies at the levels of vehicle integration, component reuse, and battery management, none of these solutions effectively address the two core requirements of the specific scenario of electric cold chain generators: first, reliable physical isolation between the mains power supply and the high-voltage power battery; and second, a multi-redundancy mechanism to achieve orderly and safe power-off through independent hardware protection circuits under unexpected conditions such as CPU failure. Therefore, existing technologies struggle to overcome the application limitations of traditional vacuum relays, making it difficult to solve core requirements such as physical isolation between mains power and the power battery, reliable switching between multiple power sources, hardware-level forced protection under extreme conditions such as CPU failure, and zero-current / zero-voltage interruption of the relay. This falls significantly short of the high safety, high reliability, long service life, and low cost requirements of actual cold chain transportation scenarios. Therefore, a new technical solution is needed to address these technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide an electric chiller power supply system, control method, and application to address the limitations of current electric chiller power supply control schemes mentioned in the background, which make it difficult to overcome the application limitations of traditional vacuum relays. This makes it difficult to solve core requirements such as physical isolation between mains power and power battery, reliable switching between multiple power sources, hardware-level forced protection under extreme conditions such as CPU failure, and relay zero-current / zero-voltage disconnection. These issues also result in significant gaps between these solutions and the requirements for high safety, high reliability, long service life, and low cost in actual cold chain transportation scenarios.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an electric chiller power supply system, comprising a power-on control circuit, a power-off control circuit, and an abnormal power-off circuit. The abnormal power-off circuit, in sequence according to the operation timing, includes a control console, a wake-up signal module, a DC-DC converter, a compressor, a monostable multivibrator, a third relay, a first delay circuit, a first relay, a second delay circuit, a second relay, a third delay circuit, a fourth relay, a bus capacitor, and an auxiliary power supply. The power-on control circuit, in sequence according to the operation timing, includes a control console, a wake-up signal module, a fourth relay, a second relay, a power battery, a pre-charging circuit, an auxiliary power supply, a bus capacitor, a CPU, a first relay, and a DC-DC converter. The power-off control circuit, in sequence according to the operation timing, includes a control console, a CPU, a compressor, a DC-DC converter, a third relay, an auxiliary power supply, a first relay, a second relay, a third delay circuit, a fourth relay, and a bus capacitor. The second relay is a vacuum relay, while the first, third, and fourth relays are all ordinary relays.

[0008] Furthermore, the wake-up signal module outputs a wake-up voltage and connects it to the coils of the second and fourth relays respectively. The coil of the second relay is connected in parallel with the second delay circuit, and the coil of the fourth relay is connected in parallel with the third delay circuit. The contacts of the fourth relay are connected in series with the negative bus of the power battery. One end of the contact of the second relay is connected to the positive bus of the power battery, and the other end is connected to one end of the contact of the third relay and the input terminal of the pre-charge circuit. The output terminal of the pre-charge circuit and the other end of the contact of the third relay are connected in parallel and then connected together to the positive bus of the power battery. The bus capacitor is connected in parallel with the auxiliary power supply, DC-DC converter, and compressor, and then connected in series between the positive and negative buses of the power battery. The enable terminals of the DC-DC converter and the compressor are respectively connected to the wake-up signal module, the CPU, the monostable trigger, and the first delay circuit. The input terminal of the first delay circuit is connected to the wake-up signal module, and its output terminal controls the coil of the first relay through a switching circuit. The contacts of the first relay are connected in series with the positive bus of the power battery and are connected in parallel with the contacts of the second and third relays.

[0009] The electric chiller power supply system configured as described above is controlled by a control method that includes normal power-on control steps, normal power-off control steps, and abnormal power-off control steps.

[0010] Furthermore, the specific operation of the normal power-on control steps is as follows: The operation console starts the wake-up signal module, outputs the wake-up voltage, and the coils of the fourth and second relays are energized in sequence, and the contacts close; after the contacts of the second and fourth relays are closed, the power battery charges the bus capacitor and auxiliary power supply through the pre-charging circuit, and the voltage of the bus capacitor rises; after the CPU is powered on, it detects the status of the pre-charging circuit, and controls the first relay contact to close after the pre-charging is completed; finally, the DC-DC receives the command through CAN communication and starts, and the system completes the power-on.

[0011] Furthermore, the specific operation of the normal power-down control steps is as follows: The operation console sends a power-off command via CAN communication. After receiving the command, the CPU controls the compressor and DC-DC to shut down, with only the auxiliary power supply operating. The CPU controls the contacts of the third relay to close, forming a series path with the already closed contacts of the second relay. This series path forms a redundant connection with the contacts of the first relay, jointly bearing the load of the auxiliary power supply. Subsequently, the CPU disconnects the contacts of the first relay. The operation console cuts off the wake-up signal of the wake-up signal module, the coil of the second relay is de-energized, and the contacts open, cutting off the weak load of the auxiliary power supply. After a delay by the third delay circuit, the coil of the fourth relay is de-energized, and the contacts open. Finally, the CPU controls the contacts of the third relay to open, the bus capacitor is discharged, and the system returns to its initial state.

[0012] Furthermore, the specific operation of the abnormal power-down control steps is as follows: The operation console issues an abnormal shutdown command, directly cutting off the wake-up signal of the wake-up signal module, and the DC-DC converter and compressor are immediately forced to shut down; the falling edge signal generated at the moment the DC-DC converter shuts down triggers the monostable multivibrator, outputting a transient high level to engage the contacts of the third relay, so as to quickly establish a current transfer path; after the wake-up signal returns to zero, after a delay by the first delay circuit, the contacts of the first relay are disconnected by the switching circuit; after a delay by the second delay circuit, the contacts of the second relay are disconnected, at which point only the weak current of the auxiliary power supply is carried; finally, after a delay by the third delay circuit, the contacts of the fourth relay are disconnected; after all contacts are disconnected, the bus capacitor discharge terminates, the auxiliary power supply stops working, and the system returns to its initial state.

[0013] In addition to the above technical solutions, the electric chiller power supply system can also be applied to the thermal management units of new energy electric vehicles or battery energy storage.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention, through a differentiated selection scheme of a single vacuum relay + three ordinary relays, not only effectively avoids the high cost and weight burden of using multiple high-current vacuum relays in traditional solutions, significantly improving the system's economy and lightweight level, but also reduces the overall assembly difficulty and subsequent maintenance costs of the circuit, enhancing the product's market competitiveness. The invention employs a three-control-loop design with strict device operation timing, deeply binding relay actions to circuit operating conditions, ensuring all relays complete switching under no-load or low-load conditions. This completely avoids arcing, effectively preventing contact adhesion and aging, significantly improving the system's lifespan and reliability, while also protecting core components such as DC-DC converters and compressors from the impact of instantaneous high currents. Therefore, the three-loop architecture designed in this invention perfectly adapts to the physical isolation requirements of dual-power supply conditions through the coordinated disconnection timing of relays: the final actions of the three loops—power-on, power-off, and abnormal power-off—can all achieve complete disconnection of the first, second, and fourth relays, allowing the positive and negative buses of the refrigeration unit and the power battery to be completely physically disconnected. The isolation effect is far superior to electrical isolation, avoiding mutual interference between the power battery and the mains power when the mains power is input. The physical isolation is achieved without the need for additional isolation devices, directly through the normal device action timing of the three loops. Without increasing circuit complexity and cost, it meets the core requirements of dual-power switching for electric refrigerated trucks and improves the system's scenario adaptability.

[0015] 2. This invention employs a dual power-down logic of software control and hardware forced switching, achieving reliable power supply protection under extreme conditions: Under normal operating conditions, the CPU controls the on / off sequence of each relay through software programs to complete orderly power-up and power-down operations, ensuring control accuracy; Under abnormal operating conditions (i.e., when CPU failure causes CAN communication interruption), the control console can directly cut off the wake-up signal, automatically triggering the power-down process through hardware-level monostable triggers and multi-stage delay circuits, forcibly shutting down the DC-DC converter and compressor, and completing the disconnection of all relays in sequence; This allows the hardware protection circuit to operate independently of the CPU, forming a redundant control system of "software as the main component and hardware as the auxiliary component," completely solving the industry problem of the inability to orderly power down due to CPU malfunction in existing technologies, and significantly improving the safety and reliability of the system.

[0016] 3. This invention divides the power supply system into three independent control loops: power-on, power-off, and abnormal power-off. Each loop has its own dedicated operation sequence and device action logic, enabling coordinated operation across the three loops. Each loop plans the device action sequence according to its own functional requirements, avoiding interference between control logics under different operating conditions. This ensures proper pre-charging during power-on, gradual current transfer during power-off, and rapid forced shutdown during abnormal power-off. Furthermore, the shared core components across the three loops allow each loop to perform its specific function, achieving device reuse while ensuring precise control paths for each operating condition. This solves the control deficiencies of traditional solutions where a single loop adapts to multiple operating conditions, achieving orderly control throughout the entire lifecycle of the chiller power supply.

[0017] 4. This invention eliminates the redundant configuration of the traditional "dual high-current vacuum relays" by designating the second relay as a vacuum relay, which is dedicated to pre-charge control and abnormal disconnection protection. The remaining first, third, and fourth relays are ordinary relays, respectively responsible for main circuit switching, current transfer, and negative bus switching. Vacuum relays no longer handle high-current load switching tasks, but only need to handle the controlled small current during pre-charge and the mA-level weak current of the auxiliary power supply during power-off / abnormal power-off. Therefore, low-current models can be selected, significantly reducing the procurement cost of vacuum relays, while also reducing the size of components and the weight of the system, adapting to the lightweight and compact design requirements of electric refrigerated trucks. Ordinary relays only complete switching under zero current / zero voltage conditions, avoiding arc loss and solving the technical problem that ordinary relays cannot be used for high-voltage bus control in traditional solutions. This enables the rational application of ordinary relays in the high-voltage power supply circuit of refrigeration units.

[0018] 5. This invention combines a vacuum relay with a pre-charging circuit, enabling the vacuum relay to simultaneously perform both pre-charging control and abnormal disconnection protection functions, achieving a high degree of circuit integration: the pre-charging process is executed by the vacuum relay, with the power battery charging the bus capacitor and auxiliary power supply via the pre-charging circuit. The current is precisely controlled by the pre-charging resistor, avoiding the surge current generated by the instantaneous charging of the bus capacitor and protecting core components such as the DC-DC converter and compressor; when circuit abnormalities such as bus short circuits occur, the vacuum relay can utilize its current-carrying breaking capability to achieve rapid disconnection protection, eliminating the need for additional protection relays, simplifying the circuit topology, and improving the circuit integration and abnormal response speed; the integration of pre-charging and protection functions allows a single device to perform multi-dimensional functions, reducing the number of components in the circuit and further reducing the probability of circuit failure.

[0019] 6. This invention connects the delay circuit in parallel with the coil, enabling the second and fourth relays to disconnect sequentially according to preset delays (T2, T3, T4) when the wake-up signal is removed, rather than simultaneously. This hardware-level delay design ensures that the fourth relay (negative bus) is always the last to disconnect during abnormal power-down, thus guaranteeing complete physical isolation between the power battery and the load and avoiding the risk of arcing or backflow caused by simultaneous disconnection. Furthermore, this operation requires no CPU intervention; complex power-down timing can be achieved solely through the hardware characteristics of the RC delay circuit, avoiding timing chaos problems during software crashes and significantly improving system robustness. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the circuit control structure of the present invention; Figure 2 This is a schematic diagram of the circuit control structure in the prior art.

[0021] The components include: 1. Control console; 2. Power battery; 3. Wake-up signal module; 4. Auxiliary power supply; 5. DC-DC converter; 6. Compressor; 7. CPU; 8. Pre-charge circuit; 9. First relay; 10. Second relay; 11. Third relay; 12. Fourth relay; 13. Monostable multivibrator; 14. First delay circuit; 1401. Second resistor; 1402. Third capacitor; 15. Second delay circuit; 1501. First capacitor; 16. Third delay circuit; 1601. First resistor; 1602. Second capacitor; 17. Switching circuit; 1701. First switching transistor; 1702. Field-effect transistor; 1703. Second switching transistor; 18. Bus capacitor. Detailed Implementation

[0022] The following examples are used to further illustrate the content of the present invention and do not limit the application of the present invention. Example 1:

[0023] Please see Figure 1 This invention provides an electric chiller power supply system, including a control console 1, a power battery 2, a wake-up signal module 3, an auxiliary power supply 4, a DC-DC converter 5, a compressor 6, a CPU (chiller central processing unit) 7, a pre-charging circuit 8 (the pre-charging circuit is a pre-charging resistor), a bus capacitor 18, a first relay 9, a second relay 10, a third relay 11, a fourth relay 12, a monostable multivibrator 13, a first delay circuit 14, a second delay circuit 15, and a third delay circuit 16; The wake-up signal module 3 outputs a wake-up voltage and connects it to the coils of the second relay 10 and the fourth relay 12 respectively. The coil of the second relay 10 is connected in parallel with the second delay circuit 15 (the second delay circuit includes the first capacitor 1501), and the coil of the fourth relay 12 is connected in parallel with the third delay circuit 16 (the third delay circuit includes the first resistor 1601 and the second capacitor 1602 connected). The contacts of the fourth relay 12 are connected in series to the negative bus of the power battery 2. One end of the contacts of the second relay 10 is connected to the positive bus of the power battery 2, and the other end is connected to one end of the contacts of the third relay 11 and the input end of the pre-charging circuit 8. The output end of the pre-charging circuit 8 and the other end of the contacts of the third relay 11 are connected in parallel to the positive bus of the power battery 2 (i.e., the load end). Bus capacitor 18 is connected in parallel with auxiliary power supply 4, DC-DC 5, and compressor 6, and then connected in series between the positive and negative busbars of power battery 2. The enable terminals of DC-DC5 and compressor 6 are respectively connected to wake-up signal module 3, CPU 7, monostable trigger 13 and first delay circuit 14 (the first delay circuit includes a second resistor 1401 and a third capacitor 1402). The input terminal of the first delay circuit 14 is connected to the wake-up signal module 3, and its output terminal controls the coil of the first relay 9 through the switching circuit 17 (the switching circuit includes a first switching transistor 1701, a field-effect transistor 1702, and a second switching transistor 1703 connected together. The switching direction of the second switching transistor 1703 is opposite to that of the field-effect transistor 1702 and the first switching transistor 1701. That is, at this time, the first switching transistor 1701 and the field-effect transistor 1702 are in the on state, while the second switching transistor 1703 is in the off state). The contacts of the first relay 9 are connected in series with the positive bus of the power battery 2 and are connected in parallel with the contacts of the second relay 10 and the third relay 11. Among them, the second relay 10 is a vacuum relay, while the first relay 9, the third relay 11, and the fourth relay 12 are all ordinary relays (electromagnetic relays can be selected as ordinary relays).

[0024] The above-mentioned devices are used to construct three control loops: The first type of control circuit is the normal power-on control circuit. The normal power-on control circuit, in the following order of operation, includes the control console 1, wake-up signal module 3, fourth relay 12, second relay 10, power battery 2, pre-charging circuit 8, auxiliary power supply 4, bus capacitor 18, CPU 7, first relay 9, and DC-DC 5. Its specific operation steps are as follows: The control console 1 activates the wake-up signal module 3, outputting a wake-up voltage (27V, sourced from the vehicle's low-voltage battery; after the DC-DC converter is cold, it can provide another power supply). The coils of the fourth relay 12 and the second relay 10 are energized sequentially (this is because the vacuum relay's contact action time is longer than that of a regular relay, so the second relay 10 of the vacuum relay operates later than the fourth relay 12 of the regular relay; due to the delayed action of the second relay 10, no current is drawn in its circuit), and the contacts close. After the contacts of the second relay 10 and the fourth relay 12 close, the power battery 2 charges the bus capacitor 18 and the auxiliary power supply 4 through the pre-charging circuit 8, and the voltage of the bus capacitor 18 rises. After the CPU 7 is energized (because the CPU's power supply is connected to the auxiliary power supply 4, the CPU 7 is energized along with the auxiliary power supply 4), the status of the pre-charging circuit 8 is detected, and after pre-charging is completed, the first relay 9's contacts are closed. Finally, the DC-DC converter receives the command via CAN communication and starts, and the system is powered on.

[0025] The second type of control circuit is the normal power-down control circuit. The normal power-down control circuit, in the following order of operation, includes control console 1, CPU 7, compressor 6, DC-DC 5, third relay 11, auxiliary power supply 4, first relay 9, second relay 10, third delay circuit 16, fourth relay 12, and bus capacitor 18. Its specific operation steps are as follows: The control console 1 sends a shutdown command via CAN communication. After receiving the command, the CPU 7 controls the compressor 6 and DC-DC 5 to shut down, leaving only the auxiliary power supply 4 to operate. The CPU 7 controls the contacts of the third relay 11 to close, forming a series circuit with the already closed contacts of the second relay 10. This series circuit forms a redundant connection with the contacts of the first relay 9, jointly bearing the load of the auxiliary power supply 4. Subsequently, the CPU 7 disconnects the contacts of the first relay 9 (since the second relay 10 and the third relay 11 are in the conducting state, the first relay 9 will be cut off at zero voltage, and no arc will be generated). Then, the control panel 1 cuts off the wake-up signal of the wake-up signal module 3, the coil of the second relay 10 is de-energized, the contacts open, and the weak load of the auxiliary power supply 4 is cut off; after a delay of the third delay circuit 16, the coil of the fourth relay 12 is de-energized and the contacts open (because the second capacitor 1602 has stored energy, the fourth relay 12 will be cut off slightly later than the second relay 10. At this time, there is no current in the main circuit, and it is cut off under zero current); finally, the CPU controls the third relay 11 to open the contacts, the bus capacitor 18 is discharged, the auxiliary power supply 4 also stops working, and the system returns to the initial state before power-on.

[0026] The third type of control circuit is the abnormal power-down circuit. The abnormal power-down circuit, in its operational sequence, includes, in order: console 1, wake-up signal module 3, DC-DC converter 5, compressor 6, monostable multivibrator 13, third relay 11, first delay circuit 14, first relay 9, second delay circuit 15, second relay 10, third delay circuit 16, fourth relay 12, bus capacitor 18, and auxiliary power supply 4. Its specific operation steps are as follows: Since the CPU is in a malfunctioning state and cannot communicate via CAN, an abnormal shutdown command is issued through the operation console 1, directly cutting off the wake-up signal of the wake-up signal module 3. DC-DC5 and compressor 6 are immediately forced to shut down (since the wake-up signal is also the enable signal for both DC-DC5 and compressor 6, the internal hardware will force DC-DC5 and compressor 6 to shut down after the wake-up signal is removed). The falling edge signal generated at the moment DC-DC5 shuts down will trigger monostable multivibrator 13, outputting a transient high level to engage the contacts of the third relay 11 (at this time, the toggle time is set to T1; once the time is up, the monostable multivibrator 13 will toggle to a steady low level, disconnecting the contacts of the third relay 11, i.e., zero current disconnection, without generating an arc), to quickly establish a current transfer path; after the wake-up signal returns to zero, after a delay of T2 by the first delay circuit 14, the first switch 1701 and field-effect transistor 1702 are turned on, and the second switch 1703 is turned off. The contacts of the first relay 9 will be connected when the second switch 1703 is turned off. The first relay 9 is disconnected (since both the third relay 11 and the second relay 10 are in the conducting state at this time, the first relay 9 is cut off with zero current); after a delay of the second delay circuit 15, the contacts of the second relay 10 are disconnected, at which time it only carries a weak current of the auxiliary power supply 4 (due to the presence of the first capacitor 1501 of the second delay circuit 15, the second relay 10 can still maintain for a period of time (this time is T3) after the wake-up signal is disconnected from DC-DC5, so that the contacts of the second relay 10 are disconnected later than the contacts of the first relay 9); finally, after a delay of the third delay circuit 16, the contacts of the fourth relay 12 are disconnected (due to the presence of the second capacitor 1602 of the third delay circuit 16, the coil of the fourth relay 12 is de-energized later than the coil of the second relay 10, and at this time the contacts of the first relay 9 and the second relay 10 are already disconnected, so the contacts of the fourth relay 12 are cut off with zero current); after all contacts are disconnected, the bus capacitor 18 discharges and the auxiliary power supply 4 stops working, and the system returns to the initial state. Example 2:

[0027] Please see Figure 1As another objective of the present invention, a thermal management unit for a new energy electric vehicle or battery energy storage is provided, wherein the thermal management unit for the new energy electric vehicle or battery energy storage is provided with the above-described electric chiller power supply system. Therefore, the thermal management unit for the new energy electric vehicle or battery energy storage can obtain any of the beneficial effects of the electric chiller power supply system described above, which will not be repeated here.

Claims

1. An electric chiller power supply system, comprising an on-state control circuit, an off-state control circuit, and an abnormal off-state circuit, characterized in that, The abnormal power-down circuit, in the order of operation, includes a control console, a wake-up signal module, a DC-DC converter, a compressor, a monostable multivibrator, a third relay, a first delay circuit, a first relay, a second delay circuit, a second relay, a third delay circuit, a fourth relay, a bus capacitor, and an auxiliary power supply. The power-on control circuit, in the order of operation, includes a control console, a wake-up signal module, a fourth relay, a second relay, a power battery, a pre-charging circuit, an auxiliary power supply, a bus capacitor, a CPU, a first relay, and a DC-DC converter. The power-down control circuit, in the order of operation, includes a control console, a CPU, a compressor, a DC-DC converter, a third relay, an auxiliary power supply, a first relay, a second relay, a third delay circuit, a fourth relay, and a bus capacitor. The second relay is a vacuum relay, while the first, third, and fourth relays are all ordinary relays.

2. The electric chiller power supply system according to claim 1, characterized in that, The wake-up signal module outputs a wake-up voltage and connects it to the coils of the second relay and the fourth relay, respectively. The coil of the second relay is connected in parallel with the second delay circuit, and the coil of the fourth relay is connected in parallel with the third delay circuit.

3. The electric chiller power supply system according to claim 2, characterized in that, The contacts of the fourth relay are connected in series to the negative bus of the power battery. One end of the contacts of the second relay is connected to the positive bus of the power battery, and the other end is connected to one end of the contacts of the third relay and the input end of the pre-charging circuit. The output end of the pre-charging circuit and the other end of the contacts of the third relay are connected in parallel to the positive bus of the power battery.

4. The electric chiller power supply system according to claim 1, characterized in that, The bus capacitor is connected in parallel with the auxiliary power supply, DC-DC converter, and compressor, and then connected in series between the positive and negative buses of the power battery.

5. The electric chiller power supply system according to claim 1, characterized in that, The enable terminals of the DC-DC converter and the compressor are respectively connected to the wake-up signal module, the CPU, the monostable trigger and the first delay circuit.

6. The electric chiller power supply system according to claim 5, characterized in that, The input terminal of the first delay circuit is connected to the wake-up signal module, and its output terminal controls the coil of the first relay through a switching circuit.

7. The electric chiller power supply system according to claim 6, characterized in that, The contacts of the first relay are connected in series with the positive bus of the power battery and are connected in parallel with the contacts of the second and third relays.

8. A control method for an electric chiller power supply system according to any one of claims 1-7, characterized in that, It includes normal power-on control procedures, normal power-off control procedures, and abnormal power-off control procedures.

9. A control method based on an electric chiller power supply system according to claim 8, characterized in that, The specific operation of the normal power-on control steps is as follows: The operation console starts the wake-up signal module, outputs the wake-up voltage, and the coils of the fourth and second relays are energized in sequence, and the contacts close; after the contacts of the second and fourth relays are closed, the power battery charges the bus capacitor and auxiliary power supply through the pre-charging circuit, and the voltage of the bus capacitor rises; after the CPU is powered on, it detects the status of the pre-charging circuit, and controls the first relay contact to close after the pre-charging is completed; finally, the DC-DC receives the command through CAN communication and starts, and the system completes the power-on.

10. A control method based on an electric chiller power supply system according to claim 8, characterized in that, The specific operation of the normal power-down control steps is as follows: The specific operation of the power-down control circuit is as follows: The operation console sends a power-off command through CAN communication. After receiving the command, the CPU controls the compressor and DC-DC to shut down, and only the auxiliary power supply works; the CPU controls the contacts of the third relay to close, so that it forms a series path with the already closed contacts of the second relay. This series branch forms a redundant connection with the contacts of the first relay, jointly bearing the load of the auxiliary power supply; then the CPU disconnects the contacts of the first relay; the operation console cuts off the wake-up signal of the wake-up signal module, the coil of the second relay is de-energized, the contacts open, and the weak load of the auxiliary power supply is cut off; after a delay by the third delay circuit, the coil of the fourth relay is de-energized, and the contacts open; finally, the CPU controls the contacts of the third relay to open, the bus capacitor is discharged, and the system returns to the initial state.

11. The control method based on an electric chiller power supply system according to claim 8, characterized in that, The specific operation of the abnormal power-down procedure is as follows: The operation console issues an abnormal shutdown command, directly cutting off the wake-up signal of the wake-up signal module, and the DC-DC converter and compressor are immediately forced to shut down; the falling edge signal generated at the moment the DC-DC converter shuts down triggers the monostable multivibrator, outputting a transient high level to engage the contacts of the third relay, so as to quickly establish a current transfer path; after the wake-up signal returns to zero, the contacts of the first relay are disconnected through the switching circuit after a delay of the first delay circuit; after a delay of the second delay circuit, the contacts of the second relay are disconnected, at which point only the weak current of the auxiliary power supply is carried; finally, after a delay of the third delay circuit, the contacts of the fourth relay are disconnected; after all contacts are disconnected, the bus capacitor discharge terminates, the auxiliary power supply stops working, and the system returns to its initial state.

12. The application of the electric chiller power supply system according to any one of claims 1-7 in the thermal management unit of new energy electric vehicles or battery energy storage.

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