Discharging device and inverter

Abstract

The invention relates to a discharging device and an inverter, and the discharging device is applied to the inverter of a new energy automobile, and comprises a switching circuit which is connected with a secondary winding of a switching power supply SMPS of the inverter, a switching circuit that turns on the switching circuit when a discharge control signal is received, and turns off the switching circuit when the discharge control signal is not received; the switching circuit is connected with the secondary winding, the discharging circuit is connected with the switching circuit and a low-voltage battery of the new energy automobile, and under the condition that the switching circuit is connected, electric energy in a direct-current link capacitor of the new energy automobile is transmitted to the low-voltage battery through the secondary winding, the switching circuit and the discharging circuit. Therefore, the waste of the voltage in the high-voltage energy storage unit can be avoided, the space and the weight of the inverter can be saved, the overheating risk in the active discharging process can be avoided, and the reliability of the discharging device is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle technology, and in particular to a discharge device and an inverter. Background Art

[0002] New energy vehicles can be powered by high-voltage batteries, using inverters to drive motors to provide power to the entire vehicle, and include other high-voltage power supply equipment. In order to output a stable voltage, the high-voltage circuit includes a high-voltage energy storage unit such as a DC link capacitor.

[0003] Usually, when the high-voltage connection is disconnected due to a fault, when the high-voltage connection is disconnected due to an accident (such as a collision), or when the high-voltage connection is disconnected due to normal power failure, in order to ensure the safety of personnel, the voltage (high voltage) in the high-voltage energy storage unit must be quickly discharged to below 60 volts (V) within a short period of time to prevent personnel from being hit by the high voltage.

[0004] In the related art, a discharge circuit can be used to achieve rapid discharge of the voltage in a high-voltage energy storage unit. The discharge circuit includes a discharge resistor having a thermistor, a switch tube for controlling the discharge resistor, and an overheat detection circuit for detecting the temperature of the discharge resistor. When the voltage in the high-voltage energy storage unit needs to be released quickly, the switch tube is turned on to consume the voltage in the high-voltage energy storage unit through the discharge resistor, and the temperature of the discharge resistor is detected through the overheat detection circuit. When the temperature detected by the overheat detection circuit exceeds a threshold, the switch tube is disconnected.

[0005] However, the voltage in the high-voltage energy storage unit is wasted in the form of heat. Moreover, since the discharge resistor is arranged, it is also necessary to arrange an additional overheat detection resistor and an overheat detection circuit, which makes the cost of the discharge circuit higher and there is an overheating risk during the active discharge process (for example, the discharge resistor may be burned when the discharge resistor is overheated); the discharge resistor needs to be arranged in a position where it can be cooled, which affects the arrangement of other components in the inverter; the discharge resistor needs to work normally throughout the life cycle of the new energy vehicle, and its durability may be at risk. Summary of the invention

[0006] In view of this, the present disclosure proposes a discharge device and an inverter, so that compared with using a discharge resistor for discharge, the present disclosure can not only avoid wasting the voltage in the high-voltage energy storage unit, but also save the space and weight of the inverter, and can also avoid the risk of overheating during active discharge, and improve the reliability of the discharge device.

[0007] According to one aspect of the present disclosure, a discharge device is provided, which is applied to an inverter of a new energy vehicle, comprising: a switch circuit connected to a secondary winding of a switching power supply (SMPS) of the inverter, wherein the switch circuit is turned on when a discharge control signal is received, and the switch circuit is turned off when the discharge control signal is not received; and a discharge circuit connected to the switch circuit and a low-voltage battery of the new energy vehicle, wherein when the switch circuit is turned on, the electric energy in the DC link capacitor of the new energy vehicle is transmitted to the low-voltage battery via the secondary winding, the switch circuit and the discharge circuit.

[0008] In one possible implementation, the discharge circuit includes: a diode, whose positive electrode is connected to the switching circuit and whose negative electrode is connected to the positive electrode of the low-voltage battery; and a capacitor, which is connected in parallel with the low-voltage battery, wherein, when the switching circuit is turned on, the current induced by the secondary winding flows into the low-voltage battery via the switching circuit, the diode and the capacitor in sequence, wherein the current corresponds to the electric energy in the DC link capacitor of the inverter.

[0009] In a possible implementation, the switch circuit includes a discharge relay, wherein when the discharge requirement exists, the discharge relay is engaged, and when the discharge requirement does not exist, the discharge relay is disconnected.

[0010] In a possible implementation, the switch circuit includes a switch tube, wherein when the discharge requirement exists, the switch tube is turned on, and when the discharge requirement does not exist, the switch tube is turned off.

[0011] In a possible implementation, the switch tube includes an IGBT or a MOSFET.

[0012] In a possible implementation, the discharge device also includes: a discharge control circuit, which is used to turn on the switch circuit when an active discharge request is received from the high-voltage inverter control module of the new energy vehicle and a dissipation signal indicating that the electric energy of the high-voltage DC bus of the new energy vehicle needs to be dissipated is obtained, wherein the electric energy of the high-voltage DC bus corresponds to the electric energy in the DC link capacitor.

[0013] In a possible implementation, the discharge device also includes a discharge control circuit, which is used to turn on the switch circuit when an active discharge request is received from the high-voltage inverter control module of the new energy vehicle, a dissipation signal indicating that the electric energy of the high-voltage DC bus of the new energy vehicle needs to be dissipated, and the low-voltage ignition power supply of the new energy vehicle is detected to be in a disconnected state, wherein the electric energy of the high-voltage DC bus corresponds to the electric energy in the DC link capacitor.

[0014] In a possible implementation, the discharge device also includes a voltage change rate detection module, which is used to detect the voltage change rate of the high-voltage DC bus, wherein when the voltage change rate exceeds a discharge threshold, the discharge control circuit obtains the dissipation signal, wherein the dissipation signal includes that the voltage change rate exceeds the discharge threshold.

[0015] In one possible implementation, the discharge device also includes a high-low voltage electrical isolation circuit for electrically isolating the high voltage part from the low voltage part in the inverter, wherein the active discharge request is transmitted from the high voltage inverter control module to the discharge control circuit via the high-low voltage electrical isolation circuit.

[0016] According to another aspect of the present disclosure, an inverter is provided for use in new energy vehicles, comprising: a switching power supply SMPS, which includes a secondary winding; the above-mentioned discharge device; and a DC link capacitor.

[0017] According to the discharge device and inverter disclosed in the present invention, the discharge device includes a switching circuit connected to the secondary winding added to the SMPS of the inverter, and a discharge circuit connected to the low-voltage battery of the new energy vehicle. When a discharge control signal is received, the switching circuit is turned on, and the current in the DC link capacitor of the new energy vehicle induced by the secondary winding flows into the low-voltage battery via the turned-on switching circuit and the discharge circuit, thereby enabling the electric energy in the DC link capacitor to be quickly released.

[0018] The present invention adds a secondary winding to the existing SMPS, and uses a switching circuit connected to the secondary winding and a discharge circuit connected to a low-voltage battery to release the voltage in the DC link capacitor. Therefore, compared with the related art of releasing the voltage in the high-voltage energy storage element via a discharge resistor, the present invention can rebound the electric energy in the DC link capacitor to the low-voltage battery. Therefore, the present invention can release the voltage in the high-voltage energy storage element while being more energy-saving and environmentally friendly.

[0019] Since the discharge resistor and the overheat detection circuit including the thermistor are deleted, although the present invention adds a secondary winding, a switching circuit and a discharge circuit to the existing SMPS, the cost of the newly added components is significantly lower than the cost of the discharge resistor and the overheat detection circuit including the thermistor. Therefore, compared with the related art of releasing the voltage in the high-voltage energy storage element through the discharge resistor, the discharge device of the present invention can reduce the material cost of the entire discharge device.

[0020] Since the discharge resistor including the thermistor and the overheat detection circuit are deleted, it is possible to avoid having to arrange the discharge resistor in a position where it can be cooled and the need to place the overheat detection circuit in the inverter, thereby saving space and weight of the inverter.

[0021] Since the discharge resistor including the thermistor and the overheat detection circuit are deleted, the risk of overheating of the discharge resistor during active discharge can be avoided. Moreover, compared with using a discharge resistor with durability risks to release the voltage in the high-voltage energy storage element, the present disclosure uses a more reliable discharge device to release the voltage in the DC link capacitor, which has higher reliability.

[0022] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

[0024] Figure 1 is a schematic diagram of an active discharge circuit in the related art.

[0025] Figure 2 is a schematic diagram of a discharge device according to this exemplary embodiment.

[0026] Figure 3 is a schematic diagram of a discharge device according to this exemplary embodiment. DETAILED DESCRIPTION

[0027] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0028] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0029] In addition, in order to better illustrate the present disclosure, numerous specific details are given in the following specific embodiments. It should be understood by those skilled in the art that the present disclosure can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present disclosure.

[0030] See also Figure 1 The inverter 10 in the related art includes a DC capacitor 103, a voltage change rate detection module 104, an electrical isolation circuit 105, a discharge control circuit 106, a switch tube 107, an overheat resistor 108, an overheat detection circuit 109, a transformer control chip 110, a switch tube 111, and a high-voltage switching power supply 112. The voltage change rate detection module 104, the electrical isolation circuit 105, the discharge control circuit 106, the switch tube 107, the discharge resistor 108, and the overheat detection circuit 109 constitute the discharge circuit 100 of the inverter 10.

[0031] During normal power-on, the high-voltage main relay 101 is engaged, the high-voltage battery 102 supplies power to the new energy vehicle, and a stable voltage is output via the DC capacitor 103. The high-voltage switching power supply 112 includes a primary winding and a power device drive power supply 1 to 3. The switch tube 111 is controlled by the transformer control chip 110 to further control the high-voltage switching power supply 112 to drive the motor of the new energy vehicle and provide power for the entire vehicle, so that the new energy vehicle works normally.

[0032] During normal operation of the new energy vehicle, there is no need to release the electrical energy in the DC capacitor 103, so the discharge control circuit 106 will not receive the discharge instruction output via the electrical isolation circuit 105, and the discharge control circuit 106 outputs a shutdown signal for disconnecting the switch tube 107, so the switch tube 107 is disconnected, and the electrical energy in the DC capacitor 103 is not consumed via the discharge resistor 108.

[0033] In contrast, when power is cut off, such as when the vehicle needs to be parked or in an emergency, the high-voltage main relay 101 is disconnected, and the electrical energy in the DC capacitor 103 needs to be released via the discharge circuit 100 in a relatively short time. Therefore, the discharge control circuit 106 receives the discharge instruction output via the electrical isolation circuit 105 and outputs a conduction signal for turning on the switch tube 107 according to the acquired voltage change rate. Therefore, the switch tube 107 is turned on, and the electrical energy in the DC capacitor 103 is consumed via the discharge resistor 108.

[0034] During the period of releasing the electric energy in the DC capacitor 103 (also referred to as during the discharge process), the temperature of the discharge resistor 108 is detected via the overheat detection circuit 109. When the temperature of the discharge resistor 108 exceeds the temperature threshold, the overheat detection circuit 109 sends an alarm signal indicating that the temperature of the discharge resistor 108 is too high to the discharge control circuit 106. When the discharge control circuit 106 receives the alarm signal, it outputs a shutdown signal for disconnecting the switch tube 107 to stop releasing the electric energy in the DC capacitor 103.

[0035] However, as described in the background technology, although the above-mentioned discharge circuit 100 can release the voltage in the DC capacitor 103, the voltage in the high-voltage energy storage unit is wasted in the form of heat. Moreover, since the discharge resistor 108 is arranged, it is also necessary to additionally arrange an overheat detection resistor and an overheat detection circuit 109, which makes the cost of the discharge circuit 100 high, and there is an overheating risk during the active discharge process (for example, the discharge resistor 108 may be burned when the discharge resistor 108 is overheated); the discharge resistor 108 needs to be arranged in a position that can be cooled, which affects the arrangement of other components in the inverter; the discharge resistor 108 needs to work normally throughout the life cycle of the new energy vehicle, and its durability may be at risk.

[0036] To this end, the present disclosure recognizes that the above-mentioned defects of the above-mentioned discharge circuit are caused by releasing the voltage in the high-voltage energy storage unit through a discharge resistor. If other discharge devices capable of releasing the voltage in the high-voltage energy storage unit are used instead of the discharge resistor, the discharge of the voltage in the high-voltage energy storage unit can also be achieved. Combined with the fact that the winding of the switching power supply can be expanded, the present disclosure further contemplates that a secondary winding can be added on the basis of the primary winding of the switching power supply to sense a current corresponding to the voltage in the high-voltage energy storage unit.

[0037] In addition, considering that if the switch circuit is turned on when the voltage in the high-voltage energy storage unit needs to be released so that the current induced by the secondary winding can be transmitted to the low-voltage battery via the discharge circuit formed by the other discharge devices, the electric energy charged back to the low-voltage battery can be reused, the present disclosure further contemplates that the secondary winding can be connected to the switch circuit, the discharge circuit can be connected to the low-voltage battery, and when the switch circuit is turned on, the electric energy in the high-voltage energy storage unit can be transmitted to the low-voltage battery via the secondary winding, the switch circuit and the discharge circuit.

[0038] Therefore, according to the present disclosure, a secondary winding is added on the basis of the primary winding of the switching power supply, the switching circuit is connected to the secondary winding, the discharge circuit is connected to the low-voltage battery, and when the switching circuit is turned on, the electric energy in the high-voltage energy storage unit is transmitted to the low-voltage battery via the secondary winding, the switching circuit and the discharge circuit.

[0039] Therefore, compared with releasing the voltage in the high-voltage energy storage element through a discharge resistor, the present disclosure can rebound the electrical energy in the DC link capacitor back to the low-voltage battery. Therefore, the present disclosure can release the voltage in the high-voltage energy storage element while being more energy-saving, environmentally friendly and reliable.

[0040] Since the discharge resistor including the thermistor and the overheat detection circuit are deleted, not only the material cost of the entire discharge device can be reduced, but also the need to arrange the discharge resistor in a position where it can be cooled can be avoided, thereby saving space and weight of the inverter, and avoiding the risk of overheating of the discharge resistor during active discharge.

[0041] Based on the above ideas, Figure 2-Figure 3 The discharge device shown can be applied to the inverter in new energy vehicles.

[0042] See also Figure 2 The discharge device 200 of this exemplary embodiment may include a switch circuit 210 and a discharge circuit 220. The switch circuit 210 is connected to a secondary winding 213 of a switching power supply of an inverter, wherein the switch circuit 210 is turned on when a discharge control signal is received, and is turned off when no discharge control signal is received.

[0043] The discharge circuit 220 is connected to the switch circuit 210 and the low-voltage battery 230 of the new energy vehicle, wherein when the switch circuit 210 is turned on, the electric energy in the DC link capacitor 103 of the new energy vehicle is transmitted to the low-voltage battery 230 via the secondary winding 213, the switch circuit 210 and the discharge circuit 220.

[0044] In this embodiment, a secondary winding 213 is added to the high-voltage switching power supply 112 of the inverter 10. In other words, the high-voltage switching power supply 112 includes a primary winding, a secondary winding 213, and power device drive power supplies 1 to 3, and the high-voltage inverter controller can control the transformer control chip 110 to energize or de-energize the primary winding of the high-voltage switching power supply 112. When the primary winding is energized, the electric energy in the DC link capacitor 103 is input to the primary winding of the high-voltage switching power supply 112, and the secondary winding 213 can sense the current in the DC link capacitor 103.

[0045] When it is necessary to release the voltage (which is a high voltage) in the DC link capacitor 103, a discharge control signal can be received, and accordingly, the switch circuit 210 is turned on, and the current in the DC link capacitor 103 induced by the secondary winding 213 flows into the discharge circuit 220 via the switch circuit 210. The discharge circuit 220 can transmit the current flowing into the DC link capacitor 103 to the low-voltage battery 230 to complete the discharge process, thereby allowing the electric energy in the DC link capacitor 103 to be rebound to the low-voltage battery 230.

[0046] Thus, after a short period of time, such as a discharge process of no more than 2 seconds, the electric energy in the DC link capacitor 103 on the high-voltage power bus will be released and transferred to the low-voltage battery 230. Therefore, when an event such as a collision occurs, rapid active discharge can be achieved.

[0047] In a possible implementation, the discharge process is completed after the voltage in the DC link capacitor 103 on the high-voltage power bus is less than a DC voltage threshold, such as 60 V. The high-voltage inverter control module can turn off the active discharge request and stop controlling the transformer control chip 110, and prepare to enter a dormant state.

[0048] Relatively speaking, when there is no need to release the voltage in the DC link capacitor 103, no discharge control signal will be received, and accordingly, the switch circuit 210 is disconnected, and the current in the DC link capacitor 103 induced by the secondary winding 213 will not flow into the discharge circuit 220 via the switch circuit 210. Naturally, the discharge circuit 220 is unable to transmit the current in the DC link capacitor 103 to the low-voltage battery 230, thereby preventing the electric energy in the DC link capacitor 103 from being rebound to the low-voltage battery 230.

[0049] In one possible implementation, the need to release the voltage in the DC link capacitor 103 may include disconnecting the high voltage connection due to a fault, disconnecting the high voltage connection due to an accident (such as a collision), or disconnecting the high voltage connection due to normal power-off.

[0050] In a possible implementation, the low-voltage battery is, for example, a 12V low-power battery.

[0051] According to the discharge device disclosed in the present invention, the discharge device includes a switching circuit connected to the secondary winding added to the SMPS of the inverter, and a discharge circuit connected to the low-voltage battery of the new energy vehicle. When a discharge control signal is received, the switching circuit is turned on, and the current in the DC link capacitor of the new energy vehicle induced by the secondary winding flows into the low-voltage battery via the turned-on switching circuit and the discharge circuit, thereby enabling the electric energy in the DC link capacitor to be quickly released.

[0052] The present invention adds a secondary winding to the existing SMPS, and uses a switching circuit connected to the secondary winding and a discharge circuit connected to a low-voltage battery to release the voltage in the DC link capacitor. Therefore, compared with the related art of releasing the voltage in the high-voltage energy storage element via a discharge resistor, the present invention can rebound the electric energy in the DC link capacitor to the low-voltage battery. Therefore, the present invention can release the voltage in the high-voltage energy storage element while being more energy-saving and environmentally friendly.

[0053] Since the discharge resistor and the overheat detection circuit including the thermistor are deleted, although the present invention adds a secondary winding, a switching circuit and a discharge circuit to the existing SMPS, the cost of the newly added components is significantly lower than the cost of the discharge resistor and the overheat detection circuit including the thermistor. Therefore, compared with the related art of releasing the voltage in the high-voltage energy storage element through the discharge resistor, the discharge device of the present invention can reduce the material cost of the entire discharge device.

[0054] Since the discharge resistor including the thermistor and the overheat detection circuit are deleted, it is possible to avoid having to arrange the discharge resistor in a position where it can be cooled and the need to place the overheat detection circuit in the inverter, thereby saving space and weight of the inverter.

[0055] Since the discharge resistor including the thermistor and the overheat detection circuit are deleted, the risk of overheating of the discharge resistor during active discharge can be avoided. Moreover, compared with using a discharge resistor with durability risks to release the voltage in the high-voltage energy storage element, the present disclosure uses a more reliable discharge device to release the voltage in the DC link capacitor, which has higher reliability.

[0056] In one possible implementation, see Figure 3 The discharge circuit 220 may include a diode 221 and a capacitor 222, wherein the positive electrode and the negative electrode of the diode 221 are respectively connected to the positive electrode of the switch circuit 210 and the low-voltage battery 230, and the capacitor 222 is connected in parallel with the low-voltage battery 230. When the switch circuit 210 is turned on, the current induced by the secondary winding 213 flows into the low-voltage battery 230 via the switch circuit 210, the diode 221 and the capacitor 222 in sequence, and the current induced by the secondary winding 213 corresponds to the electric energy in the DC link capacitor 103 of the inverter 20.

[0057] It should be noted that the discharge circuit 220 of this embodiment can be other devices in addition to the diode 221 and the capacitor 222. As long as the device can transmit the current induced by the secondary winding 213 to the low-voltage battery 230 when the switch circuit 210 is turned on, it can be used as the discharge circuit 220 of the present disclosure. Due to space limitations, the description will not be expanded.

[0058] In one possible implementation, see Figure 3 The switch circuit 210 may include a discharge relay 211 , wherein the discharge relay 211 is engaged when a discharge control signal is received, and is disconnected when a discharge control signal is not received.

[0059] In this embodiment, the relay 211 may include a switch and a resistor. When a discharge control signal is received, the switch of the relay 211 is turned on, and the current induced by the secondary winding 213 flows into the low-voltage battery 230 via the resistor of the relay 211, the diode 221 and the capacitor 222 in sequence, and rapid active discharge is performed; when no discharge control signal is received, the switch of the relay 211 is turned off, and the current induced by the secondary winding 213 does not flow into the low-voltage battery 230 via the resistor of the relay 211, the diode 221 and the capacitor 222 in sequence, and rapid active discharge is not performed.

[0060] In a possible implementation, the switch circuit 210 may include a switch tube, which is turned on when a discharge control signal is received, and is turned off when no discharge control signal is received. In a possible implementation, the switch tube includes an IGBT or a MOSFET.

[0061] In this embodiment, when a discharge control signal is received, the switch tube is turned on, and the current induced by the secondary winding 213 flows into the low-voltage battery 230 via the switch tube, the diode 221 and the capacitor 222 in sequence, and rapid active discharge is performed; when no discharge control signal is received, the switch tube is turned off, and the current induced by the secondary winding 213 does not flow into the low-voltage battery 230 via the switch tube, the diode 221 and the capacitor 222 in sequence, and rapid active discharge is not performed.

[0062] It should be noted that the switch circuit 210 of this embodiment can be other devices besides relays or switch tubes. As long as the device can be turned on when receiving a discharge control signal and turned off when not receiving a discharge control signal, it can be used as the switch circuit 210 of the present disclosure. Due to space limitations, the description will not be expanded.

[0063] In one possible implementation, see Figure 3 The discharge device 300 may further include a discharge control circuit 106, which is used to turn on the switch circuit 210 when receiving an active discharge request from a high-voltage inverter control module (not shown) of the new energy vehicle and obtaining a dissipation signal indicating that the electric energy of the high-voltage DC bus of the new energy vehicle needs to be dissipated, wherein the electric energy of the high-voltage DC bus corresponds to the electric energy in the DC link capacitor 103.

[0064] In one possible implementation, see Figure 3The discharge device 300 may further include a discharge control circuit 106, which is used to turn on the switch circuit 210 when receiving an active discharge request from a high-voltage inverter control module (not shown) of the new energy vehicle, obtaining a dissipation signal indicating that the electric energy of the high-voltage DC bus of the new energy vehicle needs to be dissipated, and detecting that the low-voltage ignition power supply of the new energy vehicle is in a disconnected state, wherein the electric energy of the high-voltage DC bus corresponds to the electric energy in the DC link capacitor 103.

[0065] In one possible implementation, see Figure 3 The discharge device 300 may further include a voltage change rate detection module 104 for detecting the voltage change rate of the high-voltage DC bus, wherein when the voltage change rate exceeds a discharge threshold, the discharge control circuit 106 obtains a dissipation signal, wherein the dissipation signal includes a voltage change rate exceeding the discharge threshold.

[0066] In one possible implementation, see Figure 3 The discharge device 300 may further include a high-low voltage electrical isolation circuit 105 for electrically isolating the high voltage part from the low voltage part in the inverter 20, wherein an active discharge request is transmitted from a high voltage inverter control module (not shown) to a discharge control circuit 106 via the high-low voltage electrical isolation circuit 105.

[0067] The rapid active discharge process of the discharge device 300 includes:

[0068] When the driver stops the vehicle and turns off the low-voltage ignition power supply of the new energy vehicle, the high-voltage battery management module disconnects the high-voltage main relay 101. The high-voltage battery management module or the vehicle controller VCU sends the shutdown status information indicating that the high-voltage main relay 101 is disconnected to the CAN network, and the VCU sends an active discharge request to the high-voltage inverter control module.

[0069] If the high-voltage inverter control module receives the shutdown status information, the active discharge request from the VCU, and detects that the low-voltage ignition power supply of the new energy vehicle is in the disconnected state (if it is a collision event, it will not detect whether the low-voltage ignition power supply is in the disconnected state), the voltage of the high-voltage DC power bus is greater than the discharge threshold, there is no fault related to the active discharge device, etc., then the high-voltage inverter control module sends an active discharge request electrical signal (corresponding to the discharge control signal, also called a discharge instruction).

[0070] The discharge command sent by the high-voltage inverter control module is transmitted to the discharge control circuit 106 through the electrical isolation circuit 105, and the discharge control circuit 106 attracts the discharge relay 211; at the same time, the high-voltage inverter control module controls the transformer control chip 110 to energize or de-energize the primary coil of the high-voltage switching power supply 212.

[0071] Thus, the current induced by the secondary coil 213 of the high-voltage switching power supply 212 flows into the low-voltage battery 230 through the discharge relay 211, the diode 221, and the voltage stabilizing capacitor 222 to complete the discharge process. Therefore, according to the discharge device 300 disclosed in the present invention, the electric energy in the DC link capacitor 103 on the high-voltage power bus can be released and transferred to the low-voltage battery 230 after a discharge process of no more than 2s.

[0072] When the voltage in the DC link capacitor 103 on the high-voltage power bus is less than 60 V, the discharge process is completed. The high-voltage inverter control module turns off the active discharge request electrical signal and stops controlling the transformer control chip 110, and prepares to enter a dormant state.

[0073] When an event such as a collision occurs that requires high-voltage discharge, the discharge device 300 of the present disclosure may be used to achieve rapid active discharge.

[0074] Therefore, compared with releasing the voltage in the high-voltage energy storage element through a discharge resistor, the present disclosure can rebound the electric energy in the DC link capacitor 103 back to the low-voltage battery 230, so the present disclosure can release the voltage in the high-voltage energy storage element 103 while being more energy-saving, environmentally friendly and having higher reliability.

[0075] Since the discharge resistor including the thermistor and the overheat detection circuit are deleted, not only the material cost of the entire discharge device 300 can be reduced, but also the need to arrange the discharge resistor in a position where it can be cooled can be avoided, thereby saving space and weight of the inverter, and avoiding the risk of overheating of the discharge resistor during active discharge.

[0076] In one possible implementation, see Figure 3 The inverter 20 may include a high-voltage switching power supply 212, a discharge device 300 and a DC link capacitor 103, wherein the high-voltage switching power supply 212 is a conventional high-voltage switching power supply (such as Figure 1 A secondary winding 213 is added on the basis of the high-voltage switching power supply 112 in the embodiment of the present invention, and the DC link capacitor 103 can be quickly and actively discharged through the secondary winding 213 and the discharge device 300.

[0077] Thus, the inverter 20 of the present disclosure can release the voltage in the high-voltage energy storage element 103 while being more energy-efficient, environmentally friendly and having higher reliability. Since the discharge resistor 108 including the thermistor and the overheat detection circuit 109 are deleted, not only can the material cost of the entire discharge device 300 be reduced, but also the need to arrange the discharge resistor 108 in a position where it can be cooled can be avoided, thereby saving the space and weight of the inverter, and the risk of overheating of the discharge resistor 108 during active discharge can be avoided.

[0078] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A discharge device, applied to an inverter of a new energy vehicle, characterized in that: include: a switch circuit connected to a secondary winding of a switching power supply SMPS of the inverter, wherein the switch circuit is turned on when a discharge control signal is received, and is turned off when the discharge control signal is not received; and A discharge circuit is connected to the switch circuit and the low-voltage battery of the new energy vehicle, wherein when the switch circuit is turned on, the electric energy in the DC link capacitor of the new energy vehicle is transmitted to the low-voltage battery via the secondary winding, the switch circuit and the discharge circuit.

2. The discharge device according to claim 1, characterized in that: The discharge circuit comprises: a diode, an anode of which is connected to the switch circuit, and a cathode of which is connected to the positive electrode of the low-voltage battery; and A capacitor connected in parallel with the low voltage battery, Wherein, when the switch circuit is turned on, the current induced by the secondary winding flows into the low-voltage battery via the switch circuit, the diode and the capacitor in sequence, wherein the current corresponds to the electric energy in the DC link capacitor of the inverter.

3. The discharge device according to claim 1, characterized in that: The switch circuit includes a discharge relay, wherein the discharge relay is engaged when the discharge control signal is received, and is disconnected when the discharge control signal is not received; or The switch circuit includes a switch tube, wherein the switch tube is turned on when the discharge control signal is received, and the switch tube is turned off when the discharge control signal is not received.

4. The discharge device according to any one of claims 1 to 3, characterized in that: Also includes: A discharge control circuit is used to turn on the switch circuit when an active discharge request is received from the high-voltage inverter control module of the new energy vehicle and a dissipation signal is obtained indicating that the electric energy of the high-voltage DC bus of the new energy vehicle needs to be dissipated, wherein the electric energy of the high-voltage DC bus corresponds to the electric energy in the DC link capacitor.

5. The discharge device according to claim 4, characterized in that: Also includes: A voltage change rate detection module is used to detect the voltage change rate of the high-voltage DC bus. Wherein, in the case that the voltage change rate exceeds the discharge threshold, the discharge control circuit acquires the dissipation signal, wherein the dissipation signal includes that the voltage change rate exceeds the discharge threshold.

6. The discharge device according to claim 5, characterized in that: Also includes: A high-low voltage electrical isolation circuit is used to electrically isolate the high voltage part from the low voltage part in the inverter. The active discharge request is transmitted from the high voltage inverter control module to the discharge control circuit via the high and low voltage electrical isolation circuit.

7. The discharge device according to any one of claims 1 to 3, characterized in that: Also includes: A discharge control circuit is used to connect the switch circuit when receiving an active discharge request from the high-voltage inverter control module of the new energy vehicle, obtaining a dissipation signal indicating that the electric energy of the high-voltage DC bus of the new energy vehicle needs to be dissipated, and detecting that the low-voltage ignition power supply of the new energy vehicle is in a disconnected state, wherein the electric energy of the high-voltage DC bus corresponds to the electric energy in the DC link capacitor.

8. The discharge device according to claim 7, characterized in that: Also includes: A voltage change rate detection module is used to detect the voltage change rate of the high-voltage DC bus. Wherein, in the case that the voltage change rate exceeds the discharge threshold, the discharge control circuit acquires the dissipation signal, wherein the dissipation signal includes that the voltage change rate exceeds the discharge threshold.

9. The discharge device according to claim 8, characterized in that: Also includes: A high-low voltage electrical isolation circuit is used to electrically isolate the high voltage part from the low voltage part in the inverter. The active discharge request is transmitted from the high voltage inverter control module to the discharge control circuit via the high and low voltage electrical isolation circuit.

10. An inverter, applied to new energy vehicles, characterized in that: include: A switching power supply SMPS, comprising a secondary winding; The discharge device according to any one of claims 1 to 9; as well as DC link capacitor.

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