Vehicle auxiliary power supply system, control method and storage medium

Abstract

The invention relates to the technical field of vehicle power supply, in particular to a vehicle auxiliary power supply system, a control method and a storage medium, and the vehicle auxiliary power supply system comprises a first pre-charging circuit, a second pre-charging circuit, an intermediate DC loop, a bidirectional DC-AC converter, a first DC-DC converter and a control unit; in the power supply mode of the high-voltage power supply end, if the control unit detects that the garage power supply end is electrified, a shutdown signal of the vehicle auxiliary power supply system is sent out; in response to the shutdown signal, pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked in a delayed manner, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the end of the current pulse period, and then a first pre-charging circuit and an AC output contactor are controlled to be disconnected; and restarting the vehicle auxiliary power supply system, and switching the bidirectional DC-AC converter from the inversion mode to the rectification mode so as to supply power through the garage power supply end. And the power supply safety is ensured.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of vehicle power supply, in particular to a vehicle auxiliary power supply system, a control method and a storage medium. BACKGROUND

[0002] In rail transit vehicles such as subways, an auxiliary power supply box is usually provided to convert high-voltage power supply into low-voltage power supply to provide power for AC and DC loads of the vehicle.

[0003] When the vehicle is parked in a maintenance garage for maintenance or testing, a garage power supply device is usually needed to be provided. In the maintenance operation, if the vehicle switches to the garage power supply, but the auxiliary power supply box or the high-voltage power supply circuit is not disconnected in time, it may cause the garage power supply and the 1500V DC high-voltage power supply to be turned on at the same time, forming an electrical loop, and thus causing equipment damage or even serious safety accidents, and vice versa. Therefore, how to avoid the simultaneous conduction of the high-voltage power supply and the garage power supply is a problem to be solved in the industry. SUMMARY

[0004] The purpose of the present disclosure is to at least provide a vehicle auxiliary power supply system, a control method and a storage medium, which can at least solve the problem of how to avoid the simultaneous conduction of the high-voltage power supply and the garage power supply, and at least achieve the effect of avoiding the simultaneous conduction of the high-voltage power supply and the garage power supply.

[0005] In a first aspect, the present disclosure provides a vehicle auxiliary power supply system, comprising: a first pre-charging circuit, a second pre-charging circuit, an intermediate DC circuit, a bidirectional DC-AC converter, a first DC-DC converter and a control unit. The high-voltage side of the intermediate DC circuit is connected to a high-voltage power supply end through the first pre-charging circuit, and the low-voltage side is connected to the DC side of the bidirectional DC-AC converter and the first DC-DC converter, respectively. The first DC-DC converter is connected to a DC output end, for converting input DC into low-voltage DC and outputting through the DC output end. The AC side of the bidirectional DC-AC converter is connected to an AC output end and the second pre-charging circuit through an AC output contactor, respectively, and the second pre-charging circuit is connected to a garage power supply end. The control unit is configured to, in the high-voltage power supply terminal power supply mode, if it is detected that the library power supply terminal has power, send a vehicle auxiliary power supply system shutdown signal; in response to the shutdown signal, delay blocking pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, then control the first pre-charge circuit and the AC output contactor to be disconnected; restart the vehicle auxiliary power supply system, and switch the bidirectional DC-AC converter from inverting mode to rectifying mode to supply power through the library power supply terminal.

[0006] Optionally, the control unit is further configured to, in the library power supply terminal power supply mode, if it is detected that the library power supply terminal is powered off and the high-voltage power supply terminal has power, send the shutdown signal; in response to the shutdown signal, delay blocking pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, then control the second pre-charge circuit and the AC output contactor to be disconnected; restart the vehicle auxiliary power supply system, and switch the bidirectional DC-AC converter from rectifying mode to inverting mode to supply power through the high-voltage power supply terminal.

[0007] Optionally, the first pre-charge circuit comprises a first pre-charge branch and a first short-circuit contactor connected in parallel; the first pre-charge branch is connected in series with a first pre-charge contactor and a first pre-charge resistor; the first pre-charge contactor is configured to control on-off of the first pre-charge branch; and the first short-circuit contactor is configured to bypass the first pre-charge branch. The second pre-charge circuit comprises a second short-circuit contactor and three second pre-charge branches corresponding to three-phase lines one by one; the second pre-charge branches are connected in series with second pre-charge resistors; three-phase contacts of the second pre-charge contactor are connected in series with the second pre-charge resistors of the three second pre-charge branches one by one, and are configured to control on-off of the three second pre-charge branches; and three-phase contacts of the second short-circuit contactor are connected in parallel with the three second pre-charge branches one by one, and are configured to bypass the three second pre-charge branches. The vehicle auxiliary power supply system further comprises an interlocking circuit. Coils of the first pre-charge contactor, the first short-circuit contactor, the second pre-charge contactor and the second short-circuit contactor are connected to a low-voltage power supply terminal through the interlocking circuit. The interlocking circuit is configured to, when the library power supply end is not powered, turn on a line between the low-voltage power supply end and the coil of the first pre-charge contactor and the coil of the first short-circuit contactor and turn off a line between the low-voltage power supply end and the coil of the second pre-charge contactor and the coil of the second short-circuit contact; when the library power supply end is powered, turn on a line between the low-voltage power supply end and the coil of the second pre-charge contactor and the coil of the second short-circuit contact and turn off a line between the low-voltage power supply end and the coil of the first pre-charge contactor and the coil of the first short-circuit contact, so that the high-voltage power supply end is interlocked with the library power supply end.

[0008] Optionally, the interlocking circuit comprises: a first branch, a first end of the first branch being connected to the low-voltage power supply end, a second end of the first branch being connected to the coil of the first pre-charge contactor through a second branch and being connected to the coil of the first short-circuit contactor through a third branch; a fourth branch, a first end of the fourth branch being connected to the low-voltage power supply end, a second end of the fourth branch being connected to the coil of the second pre-charge contactor through a fifth branch and being connected to the coil of the second short-circuit contactor through a sixth branch; a first intermediate relay, a normally open contact of the first intermediate relay being connected in series to the third branch, and a normally closed contact of the first intermediate relay being connected in series to the fourth branch; a second intermediate relay, a normally open contact of the second intermediate relay being connected in series to the second branch, and a normally closed contact of the second intermediate relay being connected in series to the fourth branch; a third intermediate relay, a normally open contact of the third intermediate relay being connected in series to the fifth branch; a fourth intermediate relay, a normally open contact of the fourth intermediate relay being connected in series to the sixth branch; an AC detection relay, a coil of the AC detection relay being connected in series between two phase lines of the library power supply end, a normally closed contact of the AC detection relay being connected in series to the first branch, and a normally open contact of the AC detection relay being connected in series to the sixth branch; The AC detection relay is configured to detect whether the library power supply end is powered.

[0009] Optionally, the control unit is specifically configured to, in the high-voltage power supply terminal power supply mode, if it is detected by the alternating current detection relay that the library power supply terminal has power, issue the shutdown signal; in response to the shutdown signal, delay blocking the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, and the coils of the alternating current output contactor, the first pre-charging contactor, the first short-circuit contactor, the first intermediate relay and the second intermediate relay are de-energized, wherein the coil of the first short-circuit contactor is de-energized when the current at the high-voltage power supply terminal is less than the first current threshold, and the coil of the alternating current output contactor is de-energized when the current at the alternating current output terminal is less than the second current threshold; restarting the vehicle auxiliary power supply system, switching the bidirectional DC-AC converter from the inverter mode to the rectifier mode, in the case that the level signal at the second end of the fourth branch is a high level signal, closing the alternating current output contactor, and controlling one of the coils of the third intermediate relay and the fourth intermediate relay to be energized in the starting order of the second pre-charging contactor and the second short-circuit contactor.

[0010] Optionally, the control unit is specifically configured to, in the high-voltage power supply terminal power supply mode, if it is detected by the alternating current detection relay that the library power supply terminal has power, issue the shutdown signal; in response to the shutdown signal, delay blocking the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, and the coils of the alternating current output contactor, the first pre-charging contactor, the first short-circuit contactor, the first intermediate relay and the second intermediate relay are de-energized, wherein the coil of the first short-circuit contactor is de-energized when the current at the high-voltage power supply terminal is less than the first current threshold, and the coil of the alternating current output contactor is de-energized when the current at the alternating current output terminal is less than the second current threshold; restarting the vehicle auxiliary power supply system, switching the bidirectional DC-AC converter from the inverter mode to the rectifier mode, in the case that the level signal at the second end of the fourth branch is a high level signal, closing the alternating current output contactor, and controlling one of the coils of the third intermediate relay and the fourth intermediate relay to be energized in the starting order of the second pre-charging contactor and the second short-circuit contactor.

[0011] Optionally, the control unit is further configured to: when receiving an external starting instruction of the vehicle auxiliary power supply system, detect the power supply state of the library power supply end and the high-voltage power supply end; if the library power supply end has power, control the bidirectional DC-AC converter to be in a rectification mode, close the AC output contactor, and control one of the coils of the third intermediate relay and the fourth intermediate relay to be electrified according to the starting sequence of the second pre-charging contactor and the second short-circuit contactor in the case that the level signal at the second end of the fourth branch is a high-level signal; if the library power supply end has no power and the high-voltage power supply end has power, control the bidirectional DC-AC converter to be in an inversion mode, close the AC output contactor, and control one of the coils of the second intermediate relay and the first intermediate relay to be electrified according to the starting sequence of the first pre-charging contactor and the first short-circuit contactor.

[0012] Optionally, the bidirectional DC-AC converter comprises: first, second, third and fourth bridge arms connected in parallel in sequence from the DC side to the AC side of the bidirectional DC-AC converter; the midpoint of the first bridge arm is connected with the neutral line; the midpoints of the second, third and fourth bridge arms are connected with the AC output end and further connected with the library power supply end through the second pre-charging circuit; The AC side of the bidirectional DC-AC converter is provided with a first current detection module and a first voltage detection module, and the DC side is provided with a second voltage detection module; the control unit is configured to, in the case that the bidirectional DC-AC converter is in a rectification mode, control the current at the AC side of the bidirectional DC-AC converter to be stable at a corresponding target value based on the current at the AC side of the bidirectional DC-AC converter detected by the first current detection module, control the voltage at the AC side of the bidirectional DC-AC converter to be stable at a corresponding target value based on the voltage at the AC side of the bidirectional DC-AC converter detected by the first voltage detection module, and control the voltage at the DC side of the bidirectional DC-AC converter to be stable at a corresponding target value based on the voltage at the DC side of the bidirectional DC-AC converter detected by the second voltage detection module.

[0013] Optionally, the low-voltage power supply end is connected with a DC bus, and the DC bus is connected with a storage battery and the DC output end respectively. The vehicle auxiliary power supply system further comprises: a charger. The first DC-DC converter is arranged in the charger and is further configured to charge the storage battery.

[0014] Optionally, the vehicle auxiliary power supply system further comprises: an output filter circuit. The AC side of the bidirectional AC-DC converter is connected with the AC output contactor through the output filter circuit.

[0015] In a second aspect, the present disclosure provides a control method of a vehicle auxiliary power supply system, applied to the vehicle auxiliary power supply system as described in any of the above, the method comprising: In the high-voltage power supply end power supply mode, if it is detected that the library power supply end has power, a shutdown signal of the vehicle auxiliary power supply system is sent out; In response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked with a time delay, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the end of the current pulse period, then the first pre-charge circuit and the AC output contactor are controlled to be disconnected; the vehicle auxiliary power supply system is restarted, and the bidirectional DC-AC converter is switched from the inversion mode to the rectification mode to be powered through the library power supply end.

[0016] Optionally, the method further comprises: In the high-voltage power supply end power supply mode, if it is detected that the library power supply end has power, a shutdown signal of the vehicle auxiliary power supply system is sent out; In response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked with a time delay, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the end of the current pulse period, then the second pre-charge circuit and the AC output contactor are controlled to be disconnected; the vehicle auxiliary power supply system is restarted, and the bidirectional DC-AC converter is switched from the rectification mode to the inversion mode to be powered through the high-voltage power supply end.

[0017] In a third aspect, the present disclosure provides a computer readable storage medium, which stores a computer program, the computer program being executed by a processor to implement the control method of the vehicle auxiliary power supply system as described in any of the above.

[0018] The present disclosure has the following beneficial effects compared with the prior art: In the vehicle auxiliary power supply system of the present disclosure, the control unit sends a shutdown signal of the vehicle auxiliary power supply system if detecting that the battery power supply end has power in the high-voltage power supply end power supply mode; in response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after a delay, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, and then the first pre-charge circuit and the AC output contactor are disconnected; the vehicle auxiliary power supply system is restarted, and the bidirectional DC-AC converter is switched from the inverter mode to the rectifier mode to be powered by the battery power supply end, at this time, the AC power input by the battery power supply end powers the AC load and the DC load alone, in this way, the switching between the rectifier mode and the inverter mode of the bidirectional DC-AC converter can be controlled by software, and the safety interlocking of the battery power supply end and the high-voltage power supply end power supply is realized. Moreover, the delay blocking of the pulse ensures the uniqueness of the state transition in the power flow switching process, avoids any possible transient double-pass state, and also avoids the direct blocking of the switching device under a large current, which produces a large voltage stress and causes damage to voltage-sensitive devices, prolongs the service life, and reduces the impact of frequent switching of the power supply mode on the service life.

[0019] It can be understood that the beneficial effects of the second and third aspects described above can be referred to the related description in the first aspect described above, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0020] One or more embodiments are illustrated by way of example in the drawings that are not intended to be limiting of the embodiments.

[0021] Figure 1 is a schematic diagram of a vehicle auxiliary power supply system provided by an embodiment of the present disclosure; Figure 2 is a flowchart of a control method of a vehicle auxiliary power supply system provided by another embodiment of the present disclosure Figure 1 ; Figure 3 is a schematic diagram of a bidirectional DC-AC converter provided by another embodiment of the present disclosure; Figure 4 is a flowchart of a control method of a vehicle auxiliary power supply system provided by another embodiment of the present disclosure Figure 2 . DETAILED DESCRIPTION

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the various embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this disclosure. The various embodiments can be combined with and referenced by each other without contradiction.

[0023] This embodiment provides a vehicle auxiliary power system, such as Figure 1 As shown, it includes: a first pre-charging circuit 11, a second pre-charging circuit 15, an intermediate DC circuit 12, a bidirectional DC-AC converter 13, a first DC-DC converter 14, and a control unit; The high-voltage side of the intermediate DC circuit 12 is connected to the high-voltage power supply terminal through the first pre-charge circuit 11, and the low-voltage side is connected to the DC side of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 respectively. The first DC-DC converter 14 is connected to the DC output terminal and is used to convert the input DC power into low-voltage DC power and output it through the DC output terminal. The AC side of the bidirectional DC-AC converter 13 is connected to the AC output terminal and the second pre-charge circuit 15 respectively through the AC output contactor KMA. The second pre-charge circuit 15 is connected to the power supply terminal. The control unit (not shown in the figure) is used to issue a shutdown signal for the vehicle auxiliary power system if power is detected at the depot power supply terminal in the high-voltage power supply mode; in response to the shutdown signal, it delays and blocks the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 so that the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 are blocked after the current pulse cycle ends; then, it controls the first pre-charge circuit 11 and the AC output contactor KMA to disconnect; and restarts the vehicle auxiliary power system by switching the bidirectional DC-AC converter 13 from inverter mode to rectifier mode to supply power through the depot power supply terminal.

[0024] The control unit is further configured to, in the library power supply mode, send a shutdown signal if it is detected that the library power supply is powered off and the high-voltage power supply is powered on; in response to the shutdown signal, delay and block the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 so that the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 are blocked after the current pulse period ends, and then control the second pre-charge circuit 15 and the AC output contactor KMA to be disconnected; and restart the vehicle auxiliary power supply system and switch the bidirectional DC-AC converter 13 from the rectification mode to the inversion mode to be powered by the high-voltage power supply.

[0025] The high-voltage power supply end is configured to input high-voltage direct current provided by a high-voltage power supply, for example, 1500V or 750V high-voltage direct current.

[0026] The intermediate direct current circuit 12 comprises, in sequence from the high-voltage side to the low-voltage side, an input filter circuit, a boost chopper circuit, and a full-bridge resonant converter. The full-bridge resonant converter comprises the second DC-DC converter.

[0027] The vehicle auxiliary power supply system further comprises a charger, and the first DC-DC converter 14 is arranged in the charger and is further configured to charge the storage battery. The storage battery is an energy storage and power supply unit of a low-voltage electrical system of the vehicle.

[0028] The vehicle auxiliary power supply system further comprises an output filter circuit 16, and the AC side of the bidirectional AC-DC converter 13 is connected to the AC output contactor KMA through the output filter circuit 16. The output filter circuit can effectively filter out harmonics.

[0029] The intermediate direct current circuit 12 is configured to convert the high-voltage direct current input by the high-voltage power supply end into intermediate direct current and provide the intermediate direct current to the bidirectional DC-AC converter 13 and the first DC-DC converter 14; and the first DC-DC converter 14 is configured to convert the input direct current into low-voltage direct current and output the low-voltage direct current through the direct current output end to supply power to a direct current load.

[0030] The first pre-charge circuit 11, the second pre-charge circuit 15, the intermediate direct current circuit 12, the bidirectional DC-AC converter 13, the output filter circuit 16, and the charger of the embodiment are arranged in an auxiliary power supply box 20.

[0031] The bidirectional DC-AC converter 13 has a DC-AC inversion mode and an AC-DC rectification mode.

[0032] In the DC-AC inverse mode of the bidirectional DC-AC converter 13, the high-voltage DC voltage input from the high-voltage power supply end is filtered by the first pre-charging circuit and then sent to the boost chopper circuit for pre-stabilization. The stabilized voltage is converted into intermediate DC by the full-bridge resonant converter. One path of the intermediate DC is input to the bidirectional DC-AC converter 13 and the output filter circuit 16, and then output to the AC output contactor KMA after being inverted and filtered, thereby obtaining a low-harmonic-content three-phase quasi-sinusoidal voltage (for example, 380V or 415V AC) and outputting three-phase AC voltage U, W and V to the AC output end. Meanwhile, the other path of the intermediate DC is converted into a high-frequency PWM voltage by the first DC-DC converter 14, and then output to the DC output end after being rectified and filtered, thereby obtaining a stable low-voltage DC (for example, 110V or 24V DC) and outputting the low-voltage DC to the DC load in the vehicle. In this way, the high-voltage power supply end can supply power to the AC load and the DC load, i.e., the high-voltage power supply end power supply mode. For example, the DC output end includes a first positive terminal BAT+ for connecting a storage battery and a second positive terminal DC110V+ and a negative terminal DC0V for connecting other DC loads. The first DC-DC converter 14 is connected to the first positive terminal via a diode D, with the positive terminal of the diode D connected to the first DC-DC converter 14 and the negative terminal connected to the first positive terminal.

[0033] The storage battery power supply end is used to input AC power supplied by the storage battery power supply.

[0034] In the AC-DC rectification mode of the bidirectional DC-AC converter 13, the AC power input from the storage battery power supply end is filtered by the second pre-charging circuit 15, and then output to the AC output end in one path and to the first DC / DC converter 14 in the other path after being rectified by the AC output contactor KMA, the output filter circuit 16 and the bidirectional DC-AC converter 13, thereby obtaining low-voltage DC. In this way, the storage battery power supply end can supply power to the AC load and the DC load, i.e., the storage battery power supply end power supply mode. In this way, the circuit of the bidirectional DC-AC converter 13 and the charger of the auxiliary power supply box 20 can be fully utilized to directly provide AC power from the storage battery power supply to the vehicle, and to provide low-voltage DC power to the vehicle through the bidirectional DC-AC converter 13 and the charger. Based on the circuit characteristics of the auxiliary power supply box 20, the vehicle AC and DC storage battery power supply function can be realized by fully utilizing the existing circuit of the auxiliary power supply box 20. Moreover, by arranging the second pre-charging circuit 15, the filter capacitor in the output filter circuit 16 and the support capacitor of the bidirectional DC-AC converter 13 can be pre-charged during the storage battery power supply process, thereby effectively reducing the capacitor impulse current and prolonging the service life of the capacitor.

[0035] When the power supply end of the library is not powered and the high-voltage power supply end is powered, the bidirectional DC-AC converter 13 is in an inverting mode, inverts the intermediate direct current on the side of the high-voltage power supply end into alternating current and outputs to the alternating current output end, cannot rectify the alternating current input by the library power supply end into direct current, and only the high-voltage power supply end supplies power to the alternating current load and the direct current load. When the power supply end of the library is powered, the bidirectional DC-AC converter 13 is in a rectifying mode, rectifies the alternating current input by the library power supply end into direct current, cannot invert the intermediate direct current on the side of the high-voltage power supply end into alternating current and output to the alternating current output end, and the power supply end of the library supplies power to the alternating current load and the direct current load, that is, the power supply mode of the power supply end of the library. In this way, the safe interlocking of the power supply of the power supply end of the library and the high-voltage power supply end is realized through the switching of the rectifying mode and the inverting mode of the bidirectional DC-AC converter 13.

[0036] In this way, a more perfect safety concept is realized: the vehicle auxiliary power supply system is in a determined and non-conflicting power supply state at any time. The power supply mode of the library power supply is ingeniously designed to be a safer mode with higher priority, that is, as long as the power supply of the power supply end of the library is effective (the power supply of the power supply end of the library needs to be operated by a person), the power supply mode of the high-voltage power supply end will be switched to the power supply mode of the power supply end of the library, further ensuring the safety of the operator and ensuring that the cabinet library power supply is not input by the high-voltage power supply at the moment and thereafter; at the same time, if the power supply of the library power supply ends, the operator can be prompted through the vehicle-mounted man-machine interface, and the vehicle driver can determine that the vehicle auxiliary power supply system cannot work according to the vehicle-mounted man-machine interface, which will further enhance the safety relationship between the vehicle and the power supply of the library.

[0037] For example, the first pre-charging circuit 11 includes a first pre-charging branch and a first short-circuit contactor KM1 connected in parallel; a first pre-charging contactor KM2 and a first pre-charging resistor R are connected in series on the first pre-charging branch; the first pre-charging contactor KM2 is used to control the on-off of the first pre-charging branch; and the first short-circuit contactor KM1 is used to bypass the first pre-charging branch.

[0038] The second pre-charging circuit 15 includes a second short-circuit contactor and three second pre-charging branches corresponding to the three-phase line; a second pre-charging resistor Rs is connected in series on the second pre-charging branch; three-phase contacts of the second pre-charging contactor SSK2 are connected in series with the second pre-charging resistor Rs of the three second pre-charging branches in one-to-one correspondence, and are used to control the on-off of the three second pre-charging branches; and three-phase contacts of the second short-circuit contactor SSK1 are connected in parallel with the three second pre-charging branches in one-to-one correspondence, and are used to bypass the three second pre-charging branches.

[0039] For example, when the high-voltage power supply end is powered, the first pre-charging contactor KM2 can be controlled to be closed to conduct the first pre-charging branch to pre-charge, and after the pre-charging is completed, the first short-circuit contactor KM1 is closed to bypass the first pre-charging branch. The second pre-charging contactor SSK2 and the second short-circuit contactor SSK1 are three-phase contactors. When the library power supply end is powered, the second pre-charging contactor SSK2 can be controlled to be closed to conduct the second pre-charging branch to pre-charge, and after the pre-charging is completed, the second short-circuit contactor SSK1 is closed to bypass the second pre-charging branch.

[0040] The bidirectional DC-AC converter 13 and the first DC-DC converter 14 include switching devices. For example, the switching devices include Insulated Gate Bipolar Transistors (IGBTs).

[0041] The control unit is provided with a configurable delay timer, and the delay time of the delay timer is used to block the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 after the current pulse period ends, so that the conduction current in the switching device can be fully attenuated to avoid generating harmful turn-off overvoltage. When the control unit receives a shutdown signal, if the shutdown signal is a shutdown signal generated by a power device fault, the pulse is immediately blocked. If the shutdown signal is not generated by a power switching device fault, the control unit starts the delay timer, and when the delay time of the delay timer ends, the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 end in the current pulse period, and the control unit no longer generates a pulse signal, that is, a hard block signal is issued, and the output of the drive circuit of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 is forced to be low. Thus, the delay blocking pulse of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 is realized. By delaying the blocking pulse, the switching device can be prevented from being directly blocked under a large current, a large voltage stress is generated, voltage-sensitive devices are damaged, the service life is prolonged, and the influence of frequent switching on the service life is reduced.

[0042] In this embodiment, the switching between the rectification mode and the inversion mode of the bidirectional DC-AC converter can be controlled by software, the safety interlocking of the library power supply end and the high-voltage power supply end is realized, the delay blocking pulse is used to ensure the uniqueness of the state transition in the power flow switching process, any possible instantaneous double-pass state is avoided, the switching device can be prevented from being directly blocked under a large current, a large voltage stress is generated, voltage-sensitive devices are damaged, the service life is prolonged, and the influence of frequent switching of the power supply mode on the service life is reduced.

[0043] In the high-voltage power supply end power supply mode, when the power supply end of the library is detected to have power, after the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 are blocked for a delay, the current of the high-voltage power supply end is detected in real time through the second current sensor arranged at the high-voltage power supply end, the first short-circuit contactor is disconnected when the current of the high-voltage power supply end is less than the first current threshold, and the AC output contactor is disconnected when the current at the AC output end is less than the second current threshold. In the library power supply end power supply mode, if it is detected that the power supply end of the library is powered off and the high-voltage power supply end has power, after the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 are blocked for a delay, the current of the power supply end of the library is detected in real time through the first current sensor of the power supply end of the library, and the AC output contactor and the second short-circuit contactor are disconnected when the current of the power supply end of the library is less than the second current threshold. In this way, the contactor segmentation operation can be performed when the current is low. The AC output contactor, the first short-circuit contactor and the second short-circuit contactor can be avoided to be disconnected under a large current, so as to cause the contact point to be oxidized by arc and accelerate the failure period of the contactor.

[0044] In the embodiment, the pulse signals of the bidirectional DC-AC converter 13 and the first DC-DC converter 14 are blocked for a delay, and then the contactor in the corresponding pre-charge circuit and the AC output contactor are disconnected. The delay blocking pulse + small current disconnection mechanism ensures the uniqueness of the state transition in the power flow switching process, avoids any possible instantaneous double-pass state, and can effectively suppress the voltage spike generated on the line parasitic inductance due to the current mutation, thereby providing deeper protection for the switching device, prolonging the service life of the switching device, effectively reducing the contactor disconnection current, avoiding large current disconnection, causing the contact point to be oxidized by arc, and thereby prolonging the service life of the contactor. In this way, the cumulative damage of the core switching device (such as the switching device in the bidirectional DC-AC converter 13 and the filter capacitor) caused by voltage and current impact during frequent power supply mode switching of the vehicle can be effectively alleviated, and the cumulative damage of the contactor device caused by current arc due to the impact of large disconnection current during power supply mode switching can be alleviated, thereby prolonging the average failure-free time (Mean Time Between Failures, MTBF) of the vehicle auxiliary power supply system. The delay blocking pulse + small current disconnection mechanism not only ensures safety, but also is a kind of active life protection mechanism. In the power path switching stage, all active devices are forced to enter the most safe off state, and then soft start after the vehicle auxiliary power supply system is stable, which greatly reduces the electrical stress and thermal stress, and can protect the expensive, difficult-to-replace switching device and supporting capacitor, contactor, etc.

[0045] The switching of the rectification mode and the inversion mode of the bidirectional DC-AC converter 13 is controlled by software, the safety interlocking of the power supply end of the library and the power supply end of the high voltage is realized, the state transition uniqueness in the power flow switching process is ensured by the delay blocking pulse + small current breaking mechanism, any possible instantaneous double-pass state is avoided, the voltage spike generated on the line parasitic inductance due to the current mutation can be effectively inhibited, deeper protection is provided for the switching device, the breaking current of the pre-charge circuit is effectively reduced, the large current breaking is avoided, and the service life of the device is prolonged.

[0046] For example, the first pre-charge circuit 11 includes a first pre-charge branch and a first short-circuit contactor KM1 connected in parallel; the first pre-charge branch is connected in series with a first pre-charge contactor KM2 and a first pre-charge resistor R; the first pre-charge contactor KM2 is used to control the on-off of the first pre-charge branch; and the first short-circuit contactor KM1 is used to bypass the first pre-charge branch.

[0047] The second pre-charge circuit 15 includes a second short-circuit contactor and three second pre-charge branches corresponding to the three-phase line; the second pre-charge branch is connected in series with a second pre-charge resistor Rs; the three-phase contact of the second pre-charge contactor SSK2 is connected in series with the second pre-charge resistor Rs of the three second pre-charge branches in one-to-one correspondence, and is used to control the on-off of the three second pre-charge branches; and the three-phase contact of the second short-circuit contactor SSK1 is connected in parallel with the three second pre-charge branches in one-to-one correspondence, and is used to bypass the three second pre-charge branches.

[0048] Correspondingly, the auxiliary power supply system of the vehicle further includes an interlocking circuit; The coils of the first pre-charge contactor KM2, the first short-circuit contactor KM1, the second pre-charge contactor SSK2 and the second short-circuit contactor SSK1 are connected to the low-voltage power supply end through the interlocking circuit; The interlocking circuit is used to, when there is no power in the power supply end of the library, turn on the line between the low-voltage power supply end and the coil of the first pre-charge contactor KM2 and the coil of the first short-circuit contactor KM1 and turn off the line between the low-voltage power supply end and the coil of the second pre-charge contactor SSK2 and the coil of the second short-circuit contactor SSK1; when there is power in the power supply end of the library, turn on the line between the low-voltage power supply end and the coil of the second pre-charge contactor SSK2 and the coil of the second short-circuit contactor SSK1 and turn off the line between the low-voltage power supply end and the coil of the first pre-charge contactor KM2 and the coil of the first short-circuit contactor KM1, so that the power supply end of the high voltage and the power supply end of the library are interlocked.

[0049] The low-voltage power supply end is used to input low-voltage direct current. For example, 110V direct current is input.

[0050] In this embodiment, on the basis of software interlocking, a hardware interlocking circuit is further set to realize safe upgrading and ensure the uniqueness of the working state of the vehicle auxiliary power supply system. When the power supply end of the warehouse has no electricity, the line between the coil of the first pre-charging contactor KM2 and the coil of the first short contactor KM1 of the low-voltage power supply end is turned on and the line between the coil of the second pre-charging contactor SSK2 and the coil of the second short contactor SSK1 of the low-voltage power supply end is turned off. When the power supply end of the warehouse has electricity, the line between the coil of the second pre-charging contactor SSK2 and the coil of the second short contactor SSK1 of the low-voltage power supply end is turned on and the line between the coil of the first pre-charging contactor KM2 and the coil of the first short contactor KM1 of the low-voltage power supply end is turned off. The high-voltage power supply end is interlocked with the power supply end of the warehouse. Based on the detection of the power supply of the warehouse, the interlocking circuit realizes the safe interlocking of the power supply of the warehouse and the high-voltage power supply. Through the safe interlocking of hardware and software, it is ensured that the power supply of the warehouse and the high-voltage power supply cannot exist at the same time, and the stability and safety of the vehicle auxiliary power supply system are ensured.

[0051] In some embodiments, as shown in Figure 1 The interlocking circuit includes: A first branch L1, a first end of the first branch L1 is connected with the low-voltage power supply end, a second end is connected with the coil of the first pre-charging contactor KM2 through a second branch L2 and is connected with the coil of the first short contactor KM1 through a third branch L3; A fourth branch L4, a first end of the fourth branch L4 is connected with the low-voltage power supply end, a second end is connected with the coil of the second pre-charging contactor SSK2 through a fifth branch L5 and is connected with the coil of the second short contactor SSK1 through a sixth branch L6; A first intermediate relay KC1, a normally open contact of the first intermediate relay KC1 is connected in series with the third branch L3, and a normally closed contact is connected in series with the fourth branch L4; A second intermediate relay KC2, a normally open contact of the second intermediate relay KC2 is connected in series with the second branch L2, and a normally closed contact is connected in series with the fourth branch L4; A third intermediate relay KC3, a normally open contact of the third intermediate relay KC3 is connected in series with the fifth branch L5; A fourth intermediate relay KC4, a normally open contact of the fourth intermediate relay KC4 is connected in series with the sixth branch L6; The coil of an alternating current detection relay KD is connected in series between the two-phase lines of the power supply end of the warehouse, a normally closed contact is connected in series with the first branch L1, and a normally open contact is connected in series with the sixth branch L6; The alternating current detection relay KD is used for detecting whether the power supply end of the warehouse has electricity.

[0052] The interlocking circuit can be arranged in the auxiliary power supply box 20.

[0053] The coils of the first short-circuit contactor KM1, the first pre-charge contactor KM2, the second short-circuit contactor SSK1, the second pre-charge contactor SSK2, the first intermediate relay KC1, the second intermediate relay KC2, the third intermediate relay KC3, and the fourth intermediate relay KC4 are also grounded, which is represented by 0V in the figure.

[0054] For example, the control unit is specifically configured to detect whether the library power supply end has power by detecting the state of the normally open contact or the normally closed contact of the AC detection relay. When the library power supply end has power, the coil of the AC detection relay is powered on, and when the library power supply end has no power, the coil of the AC detection relay is powered off. The power-on and power-off of the coil of the AC detection relay can change the state of the normally open contact or the normally closed contact. In this way, it can be quickly and accurately detected whether the library power supply end has power.

[0055] In the high-voltage power supply mode, the library power supply has no power, and the auxiliary power supply box 20 will use the high-voltage direct current input by the vehicle and the low-voltage direct current of the battery to supply power.

[0056] When the AC detection relay KD detects that the library power supply has no power and detects that the high-voltage direct current of the high-voltage power supply end and the low-voltage direct current of the battery are effective for power supply, the bidirectional DC-AC converter enters the inverter mode. According to the starting order of the first pre-charge contactor KM2 and the first short-circuit contactor KM1, the coil of the second intermediate relay KC2 and the coil of the first intermediate relay KC1 are powered on through the control signal KM1C of the first intermediate relay KC1 and the control signal KM2C of the second intermediate relay KC2, so as to start the first pre-charge contactor KM2 first and then start the first short-circuit contactor KM1. When the high-voltage power supply end is powered, at least one of the first pre-charge contactor KM2 and the first short-circuit contactor KM1 will be closed. The level signal at the second end of the fourth branch L4 serves as an enable signal SSKEN for closing the second pre-charge contactor SSK2 and the second short-circuit contactor SSK1 of the control unit, which will always be kept at a low level. When the enable signal SSKEN is at a low level, the coils of the second short-circuit contactor SSK1 and the second pre-charge contactor SSK2 cannot be powered on and work, that is, in this working mode, the library power supply cannot be connected to the circuit. After the control unit controls the coil of the first intermediate relay KC1 and the coil of the second intermediate relay KC2 to be powered off, in the case that the level signal at the second end of the fourth branch L4 is a high-level signal, when the enable signal SSKEN is at a high level, the control unit is allowed to control the second pre-charge contactor SSK2 and the second short-circuit contactor SSK1 to be closed.

[0057] When the library power supply end is powered, the auxiliary power supply box 20 will use the alternating current of the library power supply and the low-voltage direct current of the battery to supply power.

[0058] When the AC detection relay KD detects that the library power supply has power, the AC power supply end of the library power supply, the low-voltage DC power supply is effective, the bidirectional DC-AC converter enters the rectification mode, the third intermediate relay KC3 is controlled by the control signal SSK2C of the third intermediate relay KC3 to control the coil of the third intermediate relay KC3 to be energized, the second pre-charging contactor SSK2 is closed, the library power supply end outputs AC power to the vehicle AC load through the vehicle AC bus for power supply, and the library power supply end pre-charges the capacitor in the bidirectional DC-AC converter and the connected circuit through the second pre-charging circuit, when the pre-charging voltage reaches the target voltage value, the control unit controls the coil of the fourth intermediate relay KC4 to be energized by sending the control signal SSK1C of the fourth intermediate relay KC4, so that the coil of the second short-circuit contactor SSK1 is energized, thereby closing the second short-circuit contactor SSK1, bypassing the second pre-charging contactor SSK2 and the second pre-charging resistor Rs, and the input AC power is rectified into intermediate DC power by the bidirectional DC-AC converter, and then converted into low-voltage DC power by the high-frequency first DC-DC converter to supply power to the low-voltage DC load of the vehicle.

[0059] The safety interlocking process is as follows: when the library power supply has power, the coil of the AC detection relay KD detects that the socket of the library power supply is powered, the normally closed contact is opened, the coils of the first short-circuit contactor KM1 and the first pre-charging contactor KM2 cannot be powered, and thus cannot be closed, and the high-voltage power supply end of the auxiliary power supply box 20 will be isolated. When the library power supply has no power and the pantograph input has no power, the coil of the AC detection relay KD has no power, the second short-circuit contactor SSK1 and the second pre-charging contactor SSK2 cannot be closed in any case, and the first short-circuit contactor KM1 and the first pre-charging contactor KM2 are allowed to be closed. When the library power supply has no power and the pantograph input is DC 1500V high-voltage DC power, at least one of the first short-circuit contactor KM1 and the first pre-charging contactor KM2 is closed after the auxiliary power supply box is started, at this time, the enable signal SSKEN is always a low-level signal, the coils of the second short-circuit contactor SSK1 and the second pre-charging contactor SSK2 cannot be powered and work, at the same time, the control unit cannot send the control signal to energize the coils of the third intermediate relay KC3 and the fourth intermediate relay KC4 when the enable signal SSKEN is low, so that the library power supply end is isolated from the software and hardware, and thus the interlocking is formed.

[0060] In the embodiment, the interlocking of the interlocking circuit and the software and hardware of the control unit is further improved.

[0061] It should be noted that the structure of the interlocking circuit described above is only an example, and the interlocking can also be realized by other structures, which will not be listed one by one here.

[0062] For example, the control unit is also configured to: when receiving a start command from an external vehicle auxiliary power system, detect the power supply status of the storage power supply terminal and the high-voltage power supply terminal; if the storage power supply terminal is energized, control the bidirectional DC-AC converter to rectify mode, and when the level signal at the second terminal of the fourth branch is a high-level signal, close the AC output contactor, and control one of the coils of the third intermediate relay and the fourth intermediate relay to be energized according to the start sequence of the second pre-charge contactor and the second short-circuit contactor; if the storage power supply terminal is de-energized and the high-voltage power supply terminal is energized, control the bidirectional DC-AC converter to invert mode, close the AC output contactor, and control one of the coils of the second intermediate relay and the first intermediate relay to be energized according to the start sequence of the first pre-charge contactor and the first short-circuit contactor.

[0063] The start command for the vehicle auxiliary power system can be a start command from the vehicle's overall controller.

[0064] like Figure 2 As shown, specifically, upon receiving the start command, when the low-voltage power supply terminal of the vehicle's auxiliary power system is powered on, the control unit powers on and performs self-test and condition judgment. Once the control unit completes its power-on self-test and there are no serious faults, the control unit then starts the power supply voltage detection of the auxiliary power supply terminal and the high-voltage power supply terminal.

[0065] Determine if the normally open contact of the AC detection relay KD is closed. If yes (Y), enter the depot power supply mode: the bidirectional DC-AC converter enters rectification mode. When the level signal at the second terminal of the fourth branch is high, the AC output contactor closes, controlling one of the coils of the third and fourth intermediate relays to be energized according to the starting sequence of the second pre-charge contactor and the second short-circuit contactor. The depot power supply provides AC power, and the first DC-DC converter outputs DC power, continuously supplying power to the vehicle's AC and DC loads. If no (N), continue to determine if the power supply voltage at the high-voltage power supply terminal is valid.

[0066] If the supply voltage at the high-voltage power supply terminal is valid (i.e., energized), the system enters the high-voltage power supply mode: The bidirectional DC-AC converter is controlled to switch to inverter mode, the AC output contactor is closed, and one of the coils of the second intermediate relay and the first intermediate relay is energized according to the starting sequence of the first pre-charge contactor and the first short-circuit contactor. The bidirectional DC-AC converter outputs AC power, and the charger outputs DC power, continuously supplying power to the vehicle's AC and DC loads.

[0067] If the power supply voltage at the high-voltage power supply terminal is invalid, continue to detect the power supply voltage at both the backup power supply terminal and the high-voltage power supply terminal.

[0068] In the embodiment, for the starting stage, the interlocking of the interlocking circuit and the software and hardware interlocking of the control unit are cooperated to ensure the safety of the power utilization.

[0069] In some embodiments, the control unit is specifically configured to, in the high-voltage power terminal power supply mode, if it is detected by the alternating current detection relay that the power terminal of the library has power, issue a shutdown signal; in response to the shutdown signal, delay and lock the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are locked after the current pulse period ends, and the coils of the alternating current output contactor, the first pre-charging contactor, the first short-circuit contactor, the first intermediate relay and the second intermediate relay are de-energized, wherein the coil of the first short-circuit contactor is de-energized when the current at the high-voltage power terminal is less than a first current threshold, and the coil of the alternating current output contactor is de-energized when the current at the alternating current output terminal is less than a second current threshold; restart the vehicle auxiliary power supply system, switch the bidirectional DC-AC converter from the inverter mode to the rectifier mode, and in the case that the level signal at the second end of the fourth branch is a high level signal, close the alternating current output contactor, and control one of the coils of the third intermediate relay and the fourth intermediate relay to be energized according to the starting order of the second pre-charging contactor and the second short-circuit contactor.

[0070] Continuing to refer to Figure 2 , specifically, in the high-voltage power terminal power supply mode, it is judged whether the normally open contact of the alternating current detection relay KD is closed, if yes, in response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are delayed and locked, that is, the pulse is delayed and locked, and the coils of KMA, KM1 and KM2 are de-energized, wherein the coil of KM1 is de-energized when the current at the high-voltage power terminal is less than the first current threshold, and the coil of KMA is de-energized when the current at the alternating current output terminal is less than the second current threshold. After restarting, the library power terminal power supply mode is entered, the alternating current output contactor is closed, the support capacitor of the bidirectional DC-AC converter and the filter capacitor of the rear-end three-phase output filter circuit are pre-charged by the second pre-charging circuit, after the pre-charging is completed, the second pre-charging branch is bypassed, and the pulse lock of the bidirectional DC-AC converter and the first DC-DC converter is released. If the normally open contact of the alternating current detection relay KD is not closed, it is continuously judged whether the power supply voltage of the high-voltage power terminal is valid.

[0071] If the power supply voltage of the high-voltage power terminal is valid, the high-voltage power terminal power supply mode is maintained. Otherwise, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are delayed and locked, that is, the pulse is delayed and locked, the bidirectional DC-AC converter enters the standby mode, and the coils of KMA, KM1 and KM2 are de-energized, wherein the coil of KM1 is de-energized when the current at the high-voltage power terminal is less than the first current threshold, and the coil of KMA is de-energized when the current at the alternating current output terminal is less than the second current threshold.

[0072] By delaying the blocking pulse, the switch device can be prevented from being directly blocked at a large current, generating a large voltage stress di / dt, and causing damage to voltage-sensitive devices. By monitoring the current, the first short-circuit contactor KM1 and the AC output contactor KMA can be prevented from breaking at a large current, causing the main contact of the contactor to oxidize due to arc, thereby accelerating the failure cycle of the contactor.

[0073] In the high-voltage power supply end power supply mode, the interlocking circuit and the software and hardware interlocking of the control unit are cooperated with each other to realize the safety interlocking of the high-voltage power supply end and the power supply end for the library, thereby ensuring the safety of power consumption.

[0074] For example, the control unit is specifically configured to, in the power supply mode of the power supply end for the library, if it is detected by the AC detection relay that the power supply end for the library is powered off and the high-voltage power supply end is powered on, issue a shutdown signal; in response to the shutdown signal, delay blocking the pulse signal of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signal of the bidirectional DC-AC converter and the first DC-DC converter is blocked after the current pulse period ends, and the coils of the AC output contactor, the second pre-charge contactor, the second short-circuit contactor, the third intermediate relay and the fourth intermediate relay are powered off, wherein the coils of the AC output contactor and the second short-circuit contactor are powered off when the current at the AC output end is less than a second current threshold; restart the vehicle auxiliary power supply system, switch the bidirectional DC-AC converter from the rectification mode to the inversion mode, close the AC output contactor, and control one of the coils of the second intermediate relay and the coil of the first intermediate relay to be powered on according to the starting order of the first pre-charge contactor and the first short-circuit contactor.

[0075] Continuing to refer to Figure 2 , specifically, in the power supply mode of the power supply end for the library, it is judged whether the normally open contact of the AC detection relay KD is closed, if yes, the power supply mode of the power supply end for the library is maintained. Otherwise, it is judged whether the power supply voltage of the high-voltage power supply end is valid.

[0076] If the power supply voltage of the high-voltage power supply end is valid, in response to the shutdown signal, the pulse signal of the bidirectional DC-AC converter and the first DC-DC converter is delayed and blocked, the coils of KMA, SSK1 and SSK2 are powered off, wherein KMA and SSK1 are disconnected again when the current at the AC output end is less than the second current threshold, after restarting, the high-voltage power supply end power supply mode is entered, KMA is closed, the first pre-charge circuit is started, after the pre-charge is completed, the first pre-charge branch is bypassed, and the pulse blocking of the bidirectional DC-AC converter and the first DC-DC converter is released.

[0077] If the supply voltage of the high-voltage power supply end is invalid, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked by time delay, the bidirectional DC-AC converter enters standby mode, and the coils of KMA, SSK1 and SSK2 are powered off, wherein the coils of KMA and SSK1 are powered off when the current of the library power supply end is less than the second current threshold.

[0078] When the supply of the library power supply end and the high-voltage power supply end is invalid, the contactors are kept in the open state for standby.

[0079] By blocking the pulse by time delay, the switching device can be prevented from being directly blocked under a large current, a large voltage stress di / dt is generated, and voltage-sensitive devices are damaged. By monitoring the current, the second short-circuit contactor SSK1 and the AC output contactor KMA can be prevented from being broken under a large current, the main contact of the contactor is oxidized due to arc, and the failure cycle of the contactor is accelerated.

[0080] In the embodiment, under the power supply mode of the library power supply end, the safety interlocking of the high-voltage power supply end and the library power supply end is realized through the cooperation of the interlocking circuit and the software and hardware interlocking of the control unit, and the safety of power consumption is ensured.

[0081] In some embodiments, as shown in Figure 3 The bidirectional DC-AC converter comprises, in sequence from the DC side to the AC side of the bidirectional DC-AC converter, a first bridge arm S1, a second bridge arm S2, a third bridge arm S3 and a fourth bridge arm S4; the midpoint of the first bridge arm S1 is connected with the neutral line; the midpoints of the second bridge arm S2, the third bridge arm S3 and the fourth bridge arm S4 are connected with the AC output end, and are also connected with the library power supply end through a second pre-charge circuit; The AC side of the bidirectional DC-AC converter is provided with a first current detection module CS1 and a first voltage detection module VT, and the DC side is provided with a second voltage detection module VS1; the control unit is configured to, in the case that the bidirectional DC-AC converter is in the rectification mode, control the current of the AC side of the bidirectional DC-AC converter to be stable at a corresponding target value based on the current of the AC side of the bidirectional DC-AC converter detected by the first current detection module, control the voltage of the AC side of the bidirectional DC-AC converter to be stable at a corresponding target value based on the voltage of the AC side of the bidirectional DC-AC converter detected by the first voltage detection module, and control the voltage of the DC side of the bidirectional DC-AC converter to be stable at a corresponding target value based on the voltage of the DC side of the bidirectional DC-AC converter detected by the second voltage detection module.

[0082] Among the first bridge arm, the second bridge arm, the third bridge arm and the fourth bridge arm, each bridge arm includes two switching devices in series. The connection point of the two switching devices on the bridge arm is the midpoint of the bridge arm. Exemplarily, the switching device adopts a silicon carbide metal-oxide-semiconductor field-effect transistor (MOSFET).

[0083] The target value can be set according to actual needs.

[0084] Exemplarily, a first current detection module is arranged on each of the two phase lines of the AC side of the bidirectional DC-AC converter. The first current detection module can include a third current sensor. The first voltage detection module can include a voltage sensor. The second voltage detection module can include a voltage transformer.

[0085] In the case of the bidirectional DC-AC converter in the rectification mode, the current of the AC side of the bidirectional DC-AC converter detected by the first current detection module, the voltage of the AC side of the bidirectional DC-AC converter detected by the first voltage detection module, and the voltage of the DC side of the bidirectional DC-AC converter detected by the second voltage detection module are used to close-loop control the switching frequency of the switching device, so that the current of the AC side of the bidirectional DC-AC converter, the voltage of the AC side of the bidirectional DC-AC converter, and the voltage of the DC side of the bidirectional DC-AC converter are stabilized at the target value. The purpose of the embodiment is to stabilize the voltage of the DC side of the bidirectional DC-AC converter at the target value, while effectively reducing the harmonic content of the DC side current of the bidirectional DC-AC converter and further reducing the output voltage ripple of the charger when charging the battery, so as to meet the requirement of the low-voltage battery for the charging voltage quality (typically, the voltage ripple requirement is less than 5%) in the power supply mode of the power supply for the warehouse.

[0086] Exemplarily, the DC side of the bidirectional DC-AC converter is further provided with a support capacitor C0.

[0087] In the high-voltage power supply mode, the bidirectional DC-AC converter functions as a two-level inverter to convert the intermediate DC power into AC power for use by the AC load. In this case, the three-phase four-bridge-arm circuit design can simultaneously meet the requirements of three-phase AC load power supply and single-phase AC load power supply.

[0088] In the power supply mode for the warehouse, the same bidirectional DC-AC converter is reconfigured into a reverse three-phase power factor correction (PFC) adjustable current source to rectify the AC power from the power supply for the warehouse into intermediate DC power for use by the charger.

[0089] Thus, the same set of structures is used to meet the forward and reverse AC power supply requirements, and the voltage of the output intermediate DC power can be effectively reduced in harmonic content by adjusting the switching frequency of the switching device and the filter capacitor on the AC side, and further reducing the voltage ripple of the charger output to meet the low-voltage battery charging voltage quality requirement (typically <5% voltage ripple requirement) in the power supply mode of the power supply end.

[0090] In this embodiment, the function of the bidirectional DC-AC converter is dynamically reconstructed, which plays different roles in two modes and creatively reuses the functions of the core power components. This can greatly save hardware cost and space, and there is no need to set up a separate rectifier circuit for the power supply end of the power supply. At the same time, the system architecture is greatly simplified, the number of special components is reduced, and the system reliability is improved. Seamless mode switching is achieved, and since the same set of hardware is used, only the mode is changed, the switching is smoother and more efficient.

[0091] For example, the low-voltage power supply end is connected to the DC bus, and the DC bus is connected to the battery and the DC output end. Since the DC bus is connected to the battery and the DC output end of the auxiliary power supply box, in the unstarted state of the auxiliary power supply box, the low-voltage power supply end can take power from the battery to ensure timely interlocking. After the auxiliary power supply box is started, power can be taken through the DC output end, reducing the power consumption of the battery.

[0092] The present scheme proposes a high-voltage power supply and power supply interlocking power supply system based on hardware level, which ensures that the two power supply circuits are physically exclusive, effectively eliminates potential safety risks of the system, improves the intrinsic safety of maintenance operations, and ensures the safety of equipment and personnel.

[0093] The scheme realizes safe, stable and reliable power supply of the train under different working conditions through the design of the safety interlocking system of the pantograph-catenary power supply and the depot power supply. 1. Ensure the safety of power supply: through the hardware interlocking design, the simultaneous access of the pantograph-catenary power supply and the depot power supply is effectively prevented, the electrical faults, short circuits and equipment damage caused by power supply conflicts are avoided, and the safety of the vehicle electrical system is improved. 2. Improve the convenience of maintenance: when the train and other vehicles enter the depot for maintenance, the depot power supply can be safely switched, without worrying about the live traction system, thereby improving the safety and efficiency of the maintenance operation. 3. Strong system adaptability: the design is suitable for various rail transit power supply systems, meets the safe power supply requirements of the train and other vehicles under different conditions such as operation and maintenance, and has good engineering application prospect. 4. Simple structure and high reliability: the interlocking circuit adopts pure hardware electrical interlocking, avoids complex software logic control, reduces the system failure rate, is easy to implement and maintain in the later period, the core power components are reused, the number of single-point failures of the system is reduced, and the automatic mode switching avoids human error. 5. Safe operation and anti-misoperation: through the soft / hard interlocking mechanism, the power supply switching error caused by human error is effectively avoided, and the safety of the on-site operators and the vehicle is ensured. The state uniqueness is ensured through the cooperation of the hardware interlocking and the software state machine, which fundamentally eliminates the power conflict. 6. Economy: The additional special AC / DC charger is saved, which greatly reduces the system cost, volume and weight. 7. Intelligence: The full-automatic control process based on the hardware signal trigger realizes the intelligent power-on without human intervention.

[0094] The present disclosure also relates to a control method of a vehicle auxiliary power supply system, applied to the vehicle auxiliary power supply system as described in any of the above embodiments, such as Figure 4 As shown, the method comprises: Step S401: In the high-voltage power supply mode, if it is detected that the depot power supply end has power, a shutdown signal of the vehicle auxiliary power supply system is sent.

[0095] Step S401: In response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after a delay, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, then the first pre-charge circuit and the AC output contactor are controlled to be disconnected; the vehicle auxiliary power supply system is restarted, and the bidirectional DC-AC converter is switched from the inversion mode to the rectification mode to be powered by the depot power supply end.

[0096] The method of the embodiment is executed by a control unit.

[0097] In some embodiments, the control method of the vehicle auxiliary power supply system further comprises: In the library power supply terminal power supply mode, if it is detected that the library power supply terminal is powered off and the high-voltage power supply terminal is powered on, the shutdown signal is sent out; In response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked in a delay manner, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, then the second pre-charging circuit and the AC output contactor are controlled to be disconnected; the vehicle auxiliary power supply system is restarted, and the bidirectional DC-AC converter is switched from the rectification mode to the inversion mode to be powered by the high-voltage power supply terminal.

[0098] In some embodiments, steps S401 and S402 include: In the high-voltage power supply terminal power supply mode, if it is detected that the library power supply terminal is powered off and the high-voltage power supply terminal is powered on, the shutdown signal is sent out; in response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked in a delay manner, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, the coils of the AC output contactor, the first pre-charging contactor, the first short-circuit contactor, the first intermediate relay and the second intermediate relay are determined to be powered off, wherein the coil of the first short-circuit contactor is powered off when the current of the high-voltage power supply terminal is less than the first current threshold, and the coil of the AC output contactor is powered off when the current of the AC output terminal is less than the second current threshold; the vehicle auxiliary power supply system is restarted, the bidirectional DC-AC converter is switched from the inversion mode to the rectification mode, in the case that the level signal at the second end of the fourth branch is a high level signal, the AC output contactor is closed, and one of the coil of the third intermediate relay and the coil of the fourth intermediate relay is controlled to be powered on according to the starting order of the second pre-charging contactor and the second short-circuit contactor.

[0099] In some embodiments, in the library power supply terminal power supply mode, if it is detected that the library power supply terminal is powered off and the high-voltage power supply terminal is powered on, the shutdown signal is sent out; in response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked in a delay manner, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, then the second pre-charging circuit and the AC output contactor are controlled to be disconnected; the vehicle auxiliary power supply system is restarted, and the bidirectional DC-AC converter is switched from the rectification mode to the inversion mode to be powered by the high-voltage power supply terminal, including: In the power supply end for the library power supply mode, if the power supply end for the library is detected to be powered off by the AC detection relay and the high-voltage power supply end is powered on, the shutdown signal is sent out; in response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after a delay, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse period ends, and the coils of the AC output contactor, the second pre-charge contactor, the second short-circuit contactor, the third intermediate relay and the fourth intermediate relay are powered off, wherein the coils of the AC output contactor and the second short-circuit contactor are powered off when the current at the AC output end is less than the second current threshold; the vehicle auxiliary power supply system is restarted, the bidirectional DC-AC converter is switched from the rectification mode to the inversion mode, the AC output contactor is closed, and one of the coils of the second intermediate relay and the first intermediate relay is powered on according to the starting sequence of the first pre-charge contactor and the first short-circuit contactor.

[0100] In some embodiments, the control method of the vehicle auxiliary power supply system further comprises: When receiving the starting instruction of the vehicle auxiliary power supply system from the outside, the power supply states of the power supply end for the library and the high-voltage power supply end are detected; if the power supply end for the library is powered on, the bidirectional DC-AC converter is controlled to be in the rectification mode, the AC output contactor is closed when the level signal at the second end of the fourth branch is a high-level signal, and one of the coils of the third intermediate relay and the fourth intermediate relay is powered on according to the starting sequence of the second pre-charge contactor and the second short-circuit contactor; if the power supply end for the library is powered off and the high-voltage power supply end is powered on, the bidirectional DC-AC converter is controlled to be in the inversion mode, the AC output contactor is closed, and one of the coils of the second intermediate relay and the first intermediate relay is powered on according to the starting sequence of the first pre-charge contactor and the first short-circuit contactor.

[0101] The present disclosure also relates to a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the control method of the vehicle auxiliary power supply system according to any of the above embodiments.

[0102] Those skilled in the art can understand that the above embodiments are specific embodiments for implementing the present disclosure, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present disclosure.

Claims

1. A vehicle auxiliary power system, characterized in that, include: The system comprises a first pre-charging circuit, a second pre-charging circuit, an intermediate DC circuit, a bidirectional DC-AC converter, a first DC-DC converter, and a control unit. The high-voltage side of the intermediate DC circuit is connected to the high-voltage power supply terminal through the first pre-charging circuit, and the low-voltage side is connected to the DC side of the bidirectional DC-AC converter and the first DC-DC converter, respectively. The first DC-DC converter is connected to the DC output terminal and is used to convert the input DC power into low-voltage DC power and output it through the DC output terminal; The AC side of the bidirectional DC-AC converter is connected to the AC output terminal and the second pre-charge circuit respectively through an AC output contactor. The second pre-charge circuit is connected to the power supply terminal. The control unit is configured to, in the high-voltage power supply mode, if power is detected at the depot power supply terminal, issue a shutdown signal for the vehicle auxiliary power system; in response to the shutdown signal, delay and block the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse cycle ends; then, control the first pre-charge circuit and the AC output contactor to disconnect; restart the vehicle auxiliary power system, and switch the bidirectional DC-AC converter from inverter mode to rectification mode to supply power through the depot power supply terminal.

2. The vehicle auxiliary power system according to claim 1, characterized in that, The control unit is further configured to, in the power supply mode of the depot power supply terminal, if a power outage is detected at the depot power supply terminal and the high-voltage power supply terminal is powered, issue a shutdown signal; in response to the shutdown signal, delay and block the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse cycle ends; then, control the second pre-charge circuit and the AC output contactor to disconnect; restart the vehicle auxiliary power system, and switch the bidirectional DC-AC converter from rectification mode to inverter mode to supply power through the high-voltage power supply terminal.

3. The vehicle auxiliary power system according to claim 2, characterized in that, The first pre-charge circuit includes a first pre-charge branch and a first short-circuit contactor connected in parallel; the first pre-charge branch is connected in series with a first pre-charge contactor and a first pre-charge resistor; the first pre-charge contactor is used to control the on / off state of the first pre-charge branch. The first short-circuit contactor is used to bypass the first pre-charge branch; The second pre-charge circuit includes a second short-circuit contactor and three second pre-charge branches corresponding one-to-one with the three-phase lines; a second pre-charge resistor is connected in series in the second pre-charge branches; the three-phase contacts of the second pre-charge contactor are connected in series with the second pre-charge resistors of the three second pre-charge branches, respectively, to control the on / off state of the three second pre-charge branches; the three-phase contacts of the second short-circuit contactor are connected in parallel with the three second pre-charge branches, respectively, to bypass the three second pre-charge branches. The vehicle auxiliary power system also includes: an interlock circuit; The coils of the first pre-charge contactor, the first short-circuit contactor, the second pre-charge contactor, and the second short-circuit contactor are respectively connected to the low-voltage power supply terminal through the interlock circuit; The interlock circuit is used to, when the power supply terminal for the reservoir is de-energized, to connect the line between the low-voltage power supply terminal and the coils of the first pre-charge contactor and the first short-circuit contactor, and to disconnect the line between the low-voltage power supply terminal and the coils of the second pre-charge contactor and the second short-circuit contactor; and to, when the power supply terminal for the reservoir is energized, to connect the line between the low-voltage power supply terminal and the coils of the second pre-charge contactor and the second short-circuit contactor, and to disconnect the line between the low-voltage power supply terminal and the coils of the first pre-charge contactor and the first short-circuit contactor, thereby interlocking the high-voltage power supply terminal with the power supply terminal for the reservoir.

4. The vehicle auxiliary power system according to claim 3, characterized in that, The interlock circuit includes: The first branch has a first end connected to the low-voltage power supply terminal, and a second end connected to the coil of the first pre-charge contactor via the second branch and to the coil of the first short-circuit contactor via the third branch. The fourth branch has its first end connected to the low-voltage power supply terminal, and its second end connected to the coil of the second pre-charge contactor via the fifth branch and to the coil of the second short-circuit contactor via the sixth branch. The first intermediate relay has its normally open contact connected in series with the third branch and its normally closed contact connected in series with the fourth branch. The second intermediate relay has its normally open contact connected in series with the second branch and its normally closed contact connected in series with the fourth branch. The third intermediate relay, wherein the normally open contact of the third intermediate relay is connected in series with the fifth branch; The fourth intermediate relay, wherein the normally open contact of the fourth intermediate relay is connected in series with the sixth branch; An AC detection relay, wherein the coil of the AC detection relay is connected in series between two phase lines of the power supply terminal, the normally closed contact is connected in series in the first branch, and the normally open contact is connected in series in the sixth branch; The AC detection relay is used to detect whether there is power at the power supply terminal of the warehouse.

5. The vehicle auxiliary power system according to claim 4, characterized in that, The control unit is specifically configured to, in the high-voltage power supply mode, if the AC detection relay detects power at the depot power supply terminal, issue a shutdown signal; in response to the shutdown signal, delay and block the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse cycle ends, determine that the coils of the AC output contactor, the first pre-charge contactor, the first short-circuit contactor, the first intermediate relay, and the second intermediate relay are de-energized, wherein the coil of the first short-circuit contactor is de-energized when the current at the high-voltage power supply terminal is less than a first current threshold, and the coil of the AC output contactor is de-energized when the current at the AC output terminal is less than a second current threshold; restart the vehicle auxiliary power system, switch the bidirectional DC-AC converter from inverter mode to rectification mode, and when the level signal at the second terminal of the fourth branch is a high level signal, close the AC output contactor, and control one of the coils of the third intermediate relay and the fourth intermediate relay to be energized according to the starting sequence of the second pre-charge contactor and the second short-circuit contactor.

6. The vehicle auxiliary power system according to claim 4, characterized in that, The control unit is specifically configured to, in the power supply mode of the depot power supply terminal, if the AC detection relay detects that the depot power supply terminal is de-energized and the high-voltage power supply terminal is energized, issue the shutdown signal; in response to the shutdown signal, delay and block the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter, so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse cycle ends, determine that the coils of the AC output contactor, the second pre-charge contactor, the second short-circuit contactor, the third intermediate relay, and the fourth intermediate relay are de-energized, wherein the coils of the AC output contactor and the second short-circuit contactor are de-energized when the current at the AC output terminal is less than a second current threshold; restart the vehicle auxiliary power system, switch the bidirectional DC-AC converter from rectification mode to inverter mode, close the AC output contactor, and control one of the coils of the second intermediate relay and the first intermediate relay to be energized according to the starting sequence of the first pre-charge contactor and the first short-circuit contactor.

7. The vehicle auxiliary power system according to claim 4, characterized in that, The control unit is further configured to: when receiving an external start command for the vehicle auxiliary power system, detect the power supply status of the storage power supply terminal and the high-voltage power supply terminal; if the storage power supply terminal is energized, control the bidirectional DC-AC converter to rectify mode, and when the level signal at the second terminal of the fourth branch is a high-level signal, close the AC output contactor, and control one of the coils of the third intermediate relay and the fourth intermediate relay to be energized according to the start sequence of the second pre-charge contactor and the second short-circuit contactor; if the storage power supply terminal is de-energized and the high-voltage power supply terminal is energized, control the bidirectional DC-AC converter to invert mode, close the AC output contactor, and control one of the coils of the second intermediate relay and the first intermediate relay to be energized according to the start sequence of the first pre-charge contactor and the first short-circuit contactor.

8. The vehicle auxiliary power system according to claim 1, characterized in that, The bidirectional DC-AC converter includes: a first bridge arm, a second bridge arm, a third bridge arm, and a fourth bridge arm connected in parallel from the DC side to the AC side of the bidirectional DC-AC converter; the midpoint of the first bridge arm is connected to the neutral line; the midpoints of the second bridge arm, the third bridge arm, and the fourth bridge arm are connected to the AC output terminal, and are also connected to the power supply terminal through the second pre-charge circuit; The bidirectional DC-AC converter is equipped with a first current detection module and a first voltage detection module on its AC side, and a second voltage detection module on its DC side. The control unit is configured to, when the bidirectional DC-AC converter is in rectification mode, control the AC side current of the bidirectional DC-AC converter to stabilize at a corresponding target value based on the current detected by the first current detection module, control the AC side voltage of the bidirectional DC-AC converter to stabilize at a corresponding target value based on the voltage detected by the first voltage detection module, and control the DC side voltage of the bidirectional DC-AC converter to stabilize at a corresponding target value based on the voltage detected by the second voltage detection module.

9. The vehicle auxiliary power system according to claim 3, characterized in that, The low-voltage power supply terminal is connected to the DC bus, and the DC bus is connected to the battery and the DC output terminal respectively. The vehicle auxiliary power system also includes: a charger; The first DC-DC converter is disposed in the charger and is also used to charge the battery.

10. The vehicle auxiliary power system according to claim 1, characterized in that, Also includes: Output filter circuit; The AC side of the bidirectional AC-DC converter is connected to the AC output contactor through the output filter circuit.

11. A control method for a vehicle auxiliary power system, characterized in that, Applied to a vehicle auxiliary power system as described in any one of claims 1 to 10, the method comprises: In the high-voltage power supply mode, if power is detected at the depot power supply terminal, a shutdown signal is issued for the vehicle auxiliary power system. In response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are delayed and blocked so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse cycle ends. Then, the first pre-charge circuit and the AC output contactor are controlled to disconnect. The vehicle auxiliary power system is restarted, and the bidirectional DC-AC converter is switched from inverter mode to rectification mode to supply power through the battery power supply terminal.

12. The control method for a vehicle auxiliary power system according to claim 11, characterized in that, Also includes: In the power supply mode of the warehouse power supply terminal, if the power supply terminal of the warehouse power supply terminal is detected to be de-energized while the high voltage power supply terminal is energized, the shutdown signal is issued. In response to the shutdown signal, the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are delayed and blocked so that the pulse signals of the bidirectional DC-AC converter and the first DC-DC converter are blocked after the current pulse cycle ends. Then, the second pre-charge circuit and the AC output contactor are controlled to disconnect. The vehicle auxiliary power system is restarted, and the bidirectional DC-AC converter is switched from rectification mode to inverter mode to supply power through the high-voltage power supply terminal.

13. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the control method of the vehicle auxiliary power system according to any one of claims 11 to 12.

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