Voltage conversion device, refrigeration cycle system, and vehicle

Abstract

A voltage conversion device according to the present invention converts voltages inputted from a low-voltage power supply and a high-voltage power supply to voltages corresponding to an electrical compressor of a refrigeration cycle, and outputs the voltages, wherein the voltage conversion device comprises: a low-voltage-side converter that converts a DC low voltage inputted from the low-voltage power supply to a preset DC setting voltage in order to drive the electric compressor; a high-voltage-side converter that converts a DC high voltage inputted from the high-voltage power supply to a DC setting voltage; and a switching circuit unit that, in accordance with the state of voltage input from the low-voltage power supply and the high-voltage power supply, switches the state of voltage output from the low-voltage-side converter and the high-voltage-side converter to the electrical compressor.

Description

Voltage conversion device, refrigeration cycle system, and vehicle

[0001] This application claims priority to Japanese Patent Application No. 2024-029340, filed on February 29, 2024, the contents of which are incorporated herein by reference.

[0002] A so-called hybrid vehicle, which uses both an engine and a motor as a driving source for traveling, may be equipped with a refrigeration cycle (refrigeration unit) to cool a refrigerator. In this case, a DC power source is required to drive the compressor of the refrigeration cycle using an inverter. For example, Patent Document 1 discloses a configuration including an electric compressor that compresses a refrigerant, a high-voltage system that drives the electric compressor, and a low-voltage system that controls the drive of the electric compressor. In this configuration, the electric compressor is driven by high-voltage power from the high-voltage system.

[0003] Furthermore, Patent Document 2 discloses a configuration including a boost converter that boosts a low DC voltage supplied from a low-voltage power supply to a high DC voltage, an inverter that converts the high DC voltage to a high AC voltage, and an electric compressor that is driven by the inverter and compresses a refrigerant. In this configuration, the electric compressor is driven by low-voltage power supplied from a low-voltage power supply that is a battery.

[0004] JP 2016-211788 A Japanese Patent No. 7137334 A

[0005] However, when the electric compressor is driven by high-voltage power as in the configuration described in Patent Document 1, the power for driving the electric compressor is obtained from a high-voltage battery. As a result, the battery's stored charge decreases, and the power required for running the vehicle may not be obtained from the battery. Also, when the electric compressor is driven by low-voltage power as in the configuration described in Patent Document 2, the low-voltage power is obtained from a generator (alternator) driven by the engine for running the vehicle as a low-voltage power source. As a result, to operate the refrigeration cycle with the electric compressor, it may be impossible to stop the generator and the engine that drives the generator.

[0006] Furthermore, in a hybrid vehicle that uses both an engine and a motor, the engine output and the motor output may fluctuate depending on the vehicle's running conditions, etc. Even in such a hybrid vehicle, it is desirable to supply voltage to the refrigeration cycle efficiently and stably.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a voltage conversion device, a refrigeration cycle system, and a vehicle that can efficiently and stably supply voltage to a refrigeration cycle.

[0008] In order to solve the above problems, the voltage conversion device disclosed herein is a voltage conversion device that converts voltages input from a low-voltage power supply and a high-voltage power supply into voltages appropriate for an electric compressor of a refrigeration cycle and outputs the converted voltages, and includes: a low-voltage-side converter that converts the low DC voltage input from the low-voltage power supply into a predetermined DC set voltage to drive the electric compressor; a high-voltage-side converter that converts the high DC voltage input from the high-voltage power supply into the DC set voltage; and a switching circuit unit that switches the voltage output state from the low-voltage-side converter and the high-voltage-side converter to the electric compressor depending on the voltage input state from the low-voltage power supply and the high-voltage power supply.

[0009] A refrigeration cycle system according to the present disclosure includes the voltage conversion device as described above, and a refrigeration cycle having an electric compressor driven by the DC set voltage output from the voltage conversion device.

[0010] A vehicle according to the present disclosure includes a vehicle body and the above-described refrigeration cycle system mounted on the vehicle body.

[0011] According to the voltage conversion device, refrigeration cycle system, and vehicle of the present disclosure, voltage can be supplied to the refrigeration cycle efficiently and stably.

[0012] 1 is a diagram showing a schematic configuration of a vehicle equipped with a voltage conversion device and a refrigeration cycle system according to an embodiment of the present disclosure. FIG. 1 is a diagram showing a circuit configuration of the voltage conversion device. FIG. 2 is a diagram showing a state in which a high DC voltage is input from a high-voltage power supply to a high-voltage side drive circuit in the voltage conversion device according to an embodiment of the present disclosure. FIG. 3 is a diagram showing a state following FIG. 4 in the same embodiment. FIG. 5 is a diagram showing a state in which the input of a high DC voltage from a high-voltage power supply has been terminated in the voltage conversion device according to an embodiment of the present disclosure. FIG. 6 is a diagram showing a state in which a low DC voltage is input from a low-voltage power supply to a low-voltage side drive circuit in the voltage conversion device according to an embodiment of the present disclosure. FIG. 7 is a diagram showing a state following FIG. 8 in the same embodiment. FIG. 9 is a diagram showing a state in which the input of a low DC voltage from a low-voltage power supply has been terminated in the voltage conversion device according to an embodiment of the present disclosure. FIG. 11 is a diagram showing a state following FIG. 12 in the same embodiment. FIG. 13 is a diagram showing a state following FIG. 14 shows a state in which the input of a low DC voltage from a low-voltage power supply has been completed in the voltage conversion device according to an embodiment of the present disclosure, from the state shown in Fig. 14. FIG. 15 shows a state following Fig. 16. FIG. 17 shows a state following Fig. 17. FIG. 9 shows a state in which a high DC voltage is about to be input from a high-voltage power supply to a high-voltage side drive circuit in the voltage conversion device according to an embodiment of the present disclosure, from the state shown in Fig. 9.

[0013] Hereinafter, embodiments of a voltage conversion device, a refrigeration cycle system, and a vehicle according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to this embodiment. (Vehicle Configuration) As shown in FIG. 1 , a vehicle 1 includes a vehicle body 2 and a refrigeration cycle system 10. In this embodiment, the vehicle body 2 is, for example, a truck. In this case, the vehicle body 2 includes a chassis 4, a cabin 5, and a container 6. The chassis 4 includes a plurality of wheels 4w. The cabin 5 is mounted on the front of the chassis 4. A passenger can ride in the cabin 5. The container 6 is mounted on the rear of the chassis 4. The container 6 is disposed rearward of the cabin 5. The container 6 is formed in a hollow rectangular parallelepiped shape. Cargo that requires refrigeration or freezing can be accommodated inside the container 6. The vehicle body 2 may be, for example, a trailer. In this case, the vehicle body 2 includes a tractor on which the container 6 can be mounted and a cabin 5 that tows the tractor and in which a passenger can ride.

[0014] The vehicle body 2 is a so-called hybrid vehicle that includes a running engine 22 and a running motor (not shown) powered by a battery 25 to rotate and drive the wheels 4w to run the vehicle body 2. The engine 22, the battery 25, and the running motor are provided in appropriate positions on the chassis 4 or the cabin 5.

[0015] The vehicle body 2 is controlled by a vehicle controller (not shown) to control the output from the engine 22 and the output from the motor in accordance with the running state of the vehicle body 2, the operation of the accelerator, brake, etc. by the occupant, the charge level (remaining charge) of the battery 25, etc. Here, the specific output control of the engine 22 and the motor in the vehicle body 2 as a hybrid vehicle is not limited in any way in this embodiment.

[0016] The vehicle body 2 has a mode in which the vehicle body 2 runs only on output from the engine 22, a mode in which the vehicle body 2 runs only on output from a motor driven by power supplied from the battery 25, and a mode in which the vehicle body 2 runs on output from the engine 22 and output from the motor.

[0017] The vehicle body 2 includes a generator (alternator) 21 driven by an engine 22. The generator 21 is connected to an output shaft of the engine 22. The generator 21 generates electricity when rotated by the engine 22. The generator 21 is a low-voltage power supply 100, and generates a low-voltage DC voltage DL, such as 12 V or 24 V, which is lower than the voltage of a high-voltage power supply 200 (described later). In the present disclosure, the low-voltage DC voltage DL output from the low-voltage power supply 100 is, for example, 24 V.

[0018] The battery 25 is a high-voltage power supply 200, which outputs a high-voltage DC DH that is higher than the voltage of the low-voltage power supply 100. In the present disclosure, the high-voltage DC DH output from the high-voltage power supply 200 is, for example, 300 V. Note that the high-voltage DC DH output from the high-voltage power supply 200 is not limited to 300 V, and may be another voltage set by the manufacturer of the vehicle body 2, etc.

[0019] (Configuration of Refrigeration Cycle System) The refrigeration cycle system 10 mainly includes a refrigeration cycle 12 and a voltage conversion device 30 .

[0020] The refrigeration cycle 12 includes an electric compressor 15, an indoor heat exchanger 13, an outdoor heat exchanger 14, an indoor heat exchange fan (not shown), an outdoor heat exchange fan (not shown), an expansion valve (not shown), an accumulator (not shown), and a receiver (not shown). The electric compressor 15, the outdoor heat exchanger 14, and the outdoor heat exchange fan (not shown) are housed in a unit housing 7 provided at the front of the container 6 and above the cabin 5. The electric compressor 15 compresses the refrigerant. The outdoor heat exchanger 14 is disposed outside the container 11. The outdoor heat exchanger 14 cools the refrigerant supplied from the electric compressor 15 by exchanging heat with outside air. The outdoor heat exchange fan (not shown) is disposed near the outdoor heat exchanger 14. The outdoor heat exchange fan (not shown) sends outside air to the outdoor heat exchanger 14. The refrigerant cooled in the outdoor heat exchanger 14 is supplied to an expansion valve (not shown) via a receiver (not shown). The expansion valve expands (decompresses) the refrigerant supplied from the receiver.

[0021] The indoor heat exchanger 13 is provided inside the container 11. The indoor heat exchanger 13 exchanges heat between the refrigerant expanded by the expansion valve and the atmosphere inside the container 11, thereby cooling the atmosphere inside the container 11. The indoor heat exchange fan (not shown) is disposed near the indoor heat exchanger 13. The indoor heat exchange fan (not shown) cools the inside of the container 11 by sending the air cooled by the indoor heat exchanger 13 inside the container 11. The accumulator (not shown) receives the refrigerant that has passed through the indoor heat exchanger 13. The accumulator supplies the received refrigerant to the electric compressor 15.

[0022] (Configuration of Voltage Conversion Device) As shown in FIG. 2 , the voltage conversion device 30 converts the voltages input from the low-voltage power supply 100 and the high-voltage power supply 200 into voltages appropriate for the electric compressor 15 of the refrigeration cycle 12 and outputs the converted voltages. To drive the electric compressor 15, the voltage conversion device 30 converts the voltages input from the low-voltage power supply 100 and the high-voltage power supply 200 into a predetermined DC set voltage DS. The DC set voltage DS is higher than the low-voltage DC DL and lower than the high-voltage DC DH. In the present disclosure, the DC set voltage DS for driving the electric compressor 15 is set to, for example, 270 V. The DC set voltage DS may be lower than the low-voltage DC DL or higher than the high-voltage DC DH.

[0023] The voltage conversion device 30 includes a low-voltage-side converter 31, a high-voltage-side converter 41, and a switching circuit unit 50. The low-voltage-side converter 31 is a DC / DC step-up converter that converts (steps up) a low DC voltage DL (24 V) input from the low-voltage power supply 100 to a preset DC set voltage DS (270 V) for driving the electric compressor 15. The high-voltage-side converter 41 is a DC / DC step-down converter that converts (steps down) a high DC voltage DH (300 V) input from the high-voltage power supply 200 to the DC set voltage DS (270 V).

[0024] Switching circuit unit 50 switches the voltage output state from low-voltage side converter 31 and high-voltage side converter 41 to electric compressor 15 according to the voltage input state from low-voltage power supply 100 and high-voltage power supply 200. Switching circuit unit 50 includes low-voltage side drive circuit 32, low-voltage side main circuit 33, low-voltage side output circuit 34, high-voltage side drive circuit 42, high-voltage side main circuit 43, and high-voltage side output circuit 44.

[0025] The low-voltage side drive circuit 32 inputs (energizes) the DC low voltage DL from the low-voltage power supply 100 to the drive system 31c of the low-voltage side converter 31. The low-voltage side main circuit 33 inputs the DC low voltage DL from the low-voltage power supply 100 to the main system 31d of the low-voltage side converter 31. The low-voltage side drive circuit 32 and the low-voltage side main circuit 33 are provided branching off from each other at the input portion of the DC low voltage DL from the low-voltage power supply 100. The low-voltage side converter 31 boosts the DC low voltage DL input to the main system 31d to a DC set voltage DS based on the DC low voltage DL input (energized) to the drive system 31c. The low-voltage side output circuit 34 outputs the DC set voltage DS output from the main system 31d of the low-voltage side converter 31 to the electric compressor 15.

[0026] High-voltage side drive circuit 42 inputs (energizes) high DC voltage DH from high-voltage power supply 200 to drive system 41c of high-voltage side converter 41. High-voltage side main circuit 43 inputs high DC voltage DH from high-voltage power supply 200 to main system 41d of high-voltage side converter 41. High-voltage side drive circuit 42 and high-voltage side main circuit 43 are provided branching off from each other at the input section of high DC voltage DH from high-voltage power supply 200.

[0027] High-voltage converter 41 reduces the high DC voltage DH input to main system 41d to a set DC voltage DS based on the high DC voltage DH input (energized) to drive system 41c. High-voltage output circuit 44 outputs the set DC voltage DS output from main system 41d of high-voltage converter 41 to electric compressor 15. Low-voltage output circuit 34 and high-voltage output circuit 44 join together at the output to electric compressor 15.

[0028] The switching circuit unit 50 includes a high-voltage cut-off relay 51, a low-voltage side first relay 52, a low-voltage side second relay 53, a low-voltage side diode 54, a low-voltage side inrush resistor 56, a low-voltage side first capacitor 58, a low-voltage side second capacitor 59, a high-voltage side first relay 62, a high-voltage side second relay 63, a high-voltage side first relay 62, a high-voltage side second relay 63, a high-voltage side diode 64, a high-voltage side inrush resistor 66, and a high-voltage side capacitor 68.

[0029] High-voltage cut-off relay 51 includes a coil 51c and a switch 51r. Coil 51c is connected to low-voltage side output circuit 34. Switch 51r is connected upstream of high-voltage side drive circuit 42 and high-voltage side main circuit 43. Here, high-voltage cut-off relay 51, including coil 51c and switch 51r, is essentially a single component. When DC set voltage DS, output from low-voltage side converter 31 to low-voltage side output circuit 34, is applied to coil 51c, switch 51r opens. In other words, when DC set voltage DS is output to low-voltage side output circuit 34, high-voltage cut-off relay 51 cuts off high-voltage side drive circuit 42 and high-voltage side main circuit 43. This cuts off the power supply from high-voltage power supply 200 to electric compressor 15 via high-voltage side converter 41.

[0030] Low-voltage side second relay 53 includes a coil 53c and a switch 53s. Coil 53c is connected to low-voltage side drive circuit 32. Switch 53s is connected to low-voltage side main circuit 33. Here, low-voltage side second relay 53 including coil 53c and switch 53s is essentially a single component. When DC low voltage DL is input to low-voltage side drive circuit 32 and current is applied to coil 53c, low-voltage side second relay 53 closes switch 53s. As a result, when DC low voltage DL is input to low-voltage side drive circuit 32, low-voltage side second relay 53 inputs DC low voltage DL to low-voltage side main circuit 33.

[0031] Low-voltage side first relay 52 includes a coil 52c and a switch 52s. Coil 52c is connected to low-voltage side output circuit 34. Switch 52s is connected to low-voltage side main circuit 33. Switch 52s is arranged downstream of switch 53s in low-voltage side main circuit 33. Here, low-voltage side first relay 52, including coil 52c and switch 52s, is essentially a single component. When DC set voltage DS output from low-voltage side converter 31 is applied to coil 52c, switch 52s closes in low-voltage side first relay 52. ​​As a result, when DC set voltage DS is output to low-voltage side output circuit 34, low-voltage side first relay 52 inputs DC low voltage DL to low-voltage side main circuit 33.

[0032] Low-voltage side inrush resistor 56 is arranged in parallel with switch 52s of low-voltage side first relay 52 provided in low-voltage side main circuit 33. When switch 53s of low-voltage side second relay 53 is closed, DC low voltage DL is passed through low-voltage side inrush resistor 56. DC set voltage DS output from low-voltage side converter 31 is passed through coil 52c of low-voltage side first relay 52, and DC low voltage DL is passed through low-voltage side inrush resistor 56 until switch 52s is closed. As a result, low-voltage side inrush resistor 56 suppresses DC low voltage DL from rushing into low-voltage side converter 31 until switch 52s is closed. After switch 52s is closed, current flow to low-voltage side inrush resistor 56 is cut off.

[0033] Low-voltage side diode 54 is provided in low-voltage side output circuit 34. Low-voltage side diode 54 outputs DC set voltage DS from low-voltage side converter 31 only to electric compressor 15. Low-voltage side diode 54 prevents backflow of DC set voltage DS from high-voltage side output circuit 44 to coils 51c, 52c.

[0034] Low-voltage side first capacitor 58 is provided in low-voltage side drive circuit 32. Low-voltage side first capacitor 58 is arranged upstream of coil 53c in low-voltage side drive circuit 32. Low-voltage side first capacitor 58 stores electricity when DC low voltage DL is input to low-voltage side drive circuit 32. When the input of DC low voltage DL to low-voltage side drive circuit 32 is interrupted, low-voltage side first capacitor 58 discharges and maintains the voltage supply to coil 53c and drive system 31c of low-voltage side converter 31 for a certain period of time.

[0035] Low-voltage side second capacitor 59 is provided in low-voltage side output circuit 34. Low-voltage side second capacitor 59 is located downstream of coils 51c, 52c and low-voltage side diode 54 in low-voltage side output circuit 34. Low-voltage side second capacitor 59 stores electricity when DC set voltage DS is output to low-voltage side output circuit 34. When the output of DC set voltage DS to low-voltage side output circuit 34 is interrupted, low-voltage side second capacitor 59 discharges and maintains the voltage supply to electric compressor 15 for a certain period of time. In addition, diode 57 is provided downstream of low-voltage side second capacitor 59 to prevent backflow of DC set voltage DS from high-voltage side output circuit 44 to low-voltage side second capacitor 59.

[0036] The high-voltage side second relay 63 includes a coil 63c and a switch 63s. The coil 63c is connected to the high-voltage side drive circuit 42. The switch 63s is connected to the high-voltage side main circuit 43. Here, the high-voltage side second relay 63 including the coil 63c and the switch 63s is essentially a single component. When the high-voltage DC voltage DH is input to the high-voltage side drive circuit 42 and the coil 63c is energized, the switch 63s of the high-voltage side second relay 63 closes. As a result, when the high-voltage DC voltage DH is input to the high-voltage side drive circuit 42, the high-voltage side second relay 63 inputs the high-voltage DC voltage DH to the high-voltage side main circuit 43.

[0037] High-voltage side first relay 62 includes a coil 62c and a switch 62s. Coil 62c is connected to high-voltage side output circuit 44. Switch 62s is connected to high-voltage side main circuit 43. Switch 62s is arranged downstream of switch 63s in high-voltage side main circuit 43. Here, high-voltage side first relay 62, including coil 62c and switch 62s, is essentially a single component. In high-voltage side first relay 62, switch 62s closes when DC set voltage DS output from high-voltage side converter 41 is applied to coil 62c. As a result, when DC set voltage DS is output to high-voltage side output circuit 44, high-voltage side first relay 62 inputs DC high voltage DH to high-voltage side main circuit 43.

[0038] High-voltage side inrush resistor 66 is arranged in parallel with switch 62s of high-voltage side first relay 62 provided in high-voltage side main circuit 43. When switch 63s of high-voltage side second relay 63 is closed, high DC voltage DH is input to high-voltage side inrush resistor 66. DC set voltage DS output from high-voltage side converter 41 is applied to coil 62c of high-voltage side first relay 62, and high DC voltage DH is applied to high-voltage side inrush resistor 66 until switch 62s is closed. As a result, high-voltage side inrush resistor 66 suppresses high DC voltage DH from inrush into high-voltage side converter 41 until switch 62s is closed. After switch 62s is closed, current flow to high-voltage side inrush resistor 66 is cut off.

[0039] High-voltage side diode 64 is provided in high-voltage side output circuit 44. High-voltage side diode 64 outputs DC set voltage DS only to electric compressor 15 from high-voltage side converter 41. High-voltage side diode 64 prevents DC set voltage DS from flowing back from high-voltage side output circuit 44 to coil 62c.

[0040] High-voltage side capacitor 68 is provided in high-voltage side drive circuit 42. High-voltage side capacitor 68 is arranged upstream of coil 63c in high-voltage side drive circuit 42. High-voltage side capacitor 68 stores electricity when high DC voltage DH is input to high-voltage side drive circuit 42. When the input of high DC voltage DH to high-voltage side drive circuit 42 is interrupted, high-voltage side capacitor 68 discharges and maintains the voltage supply to coil 63c and drive system 41c of high-voltage side converter 41 for a certain period of time.

[0041] When the switching circuit unit 50 of the voltage conversion device 30 receives the low DC voltage DL only from the low-voltage power supply 100, the switching circuit unit 50 converts the low DC voltage DL using the low-voltage-side converter 31, and outputs the DC set voltage DS to the electric compressor 15. When the high DC voltage DH is received only from the high-voltage power supply 200, the switching circuit unit 50 converts the high DC voltage DH using the high-voltage-side converter 41, and outputs the DC set voltage DS to the electric compressor 15. When the low DC voltage DL from the low-voltage power supply 100 and the high DC voltage DH from the high-voltage power supply 200 are received, the switching circuit unit 50 outputs the DC set voltage DS to the electric compressor 15, ... and the DC set voltage DS to the electric compressor 15, the DC set voltage DS to the electric compressor 15. When the low DC voltage DL from the low-voltage power supply 100 and the high DC voltage DH from the high-voltage power supply 200 are received, the switching circuit unit 50 converts the high DC voltage DH using the high

[0042] (Operation of Voltage Conversion Device 30) Next, a description will be given of the operation of the above-described voltage conversion device 30. For example, as shown in Fig. 2, when no voltage is supplied from the high-voltage power supply 200 or the low-voltage power supply 100, only the switch 51r is closed, and the other switches 53s, 52s, 63s, and 62s are open.

[0043] (Voltage Supply from High-Voltage Power Supply) From this state, as shown in Fig. 3, when high-voltage power supply 200 supplies high-voltage DC voltage DH, current is passed through high-voltage side drive circuit 42. This causes high-voltage DC voltage DH to pass current through drive system 41c of high-voltage side converter 41. Furthermore, input of high-voltage DC voltage DH to high-voltage side drive circuit 42 passes current through coil 63c of second high-voltage relay 63, and charges high-voltage side capacitor 68.

[0044] As shown in FIG. 4 , when the coil 63c of the high-voltage side second relay 63 is energized, the switch 63s provided in the high-voltage side main circuit 43 is closed. Then, the high DC voltage DH from the high-voltage power supply 200 is input to the high-voltage side main circuit 43. The high DC voltage DH input to the high-voltage side main circuit 43 initially passes through the high-voltage side inrush resistor 66 and is input to the main system 41d of the high-voltage side converter 41. This suppresses the high DC voltage DH from inrush into the high-voltage side converter 41. The high DC voltage DH input to the high-voltage side converter 41 is stepped down to the DC set voltage DS and supplied to the electric compressor 15 via the high-voltage side output circuit 44. This allows the refrigeration cycle system 10 to begin operating using the voltage supplied from the high-voltage power supply 200. At this time, the DC set voltage DS is output to the high-voltage side output circuit 44, energizing the coil 62c of the high-voltage side first relay 62.

[0045] 5, when the coil 62c of the high-voltage side first relay 62 is energized, the switch 62s provided in the high-voltage side main circuit 43 closes. As a result, the high DC voltage DH from the high-voltage power supply 200 is input directly to the high-voltage side converter 41 without passing through the high-voltage side inrush resistor 66. As a result, the high DC voltage DH that was suppressed by the high-voltage side inrush resistor 66 returns to its original voltage.

[0046] Subsequently, when the supply of DC high voltage DH from high-voltage power supply 200 is stopped from the state shown in FIG. 5 , as shown in FIG. 6 , the input of DC high voltage DH to high-voltage side drive circuit 42 and high-voltage side main circuit 43 and the output of DC set voltage DS from high-voltage side converter 41 are stopped. This causes current to flow through coil 62c of high-voltage side first relay 62, and switch 62s opens. At this time, the charge stored in high-voltage side capacitor 68 is released, maintaining voltage supply to coil 63c of high-voltage side second relay 63 and drive system 41c of high-voltage side converter 41 for a certain period of time. This causes switch 63s to remain closed. Furthermore, high-voltage side converter 41 prevents its operation from ceasing while power is supplied to main system 41d. When high-voltage side capacitor 68 finishes discharging, current to coil 63c is lost, switch 63s opens, and the state returns to that shown in FIG. 2 .

[0047] (Voltage Supply from Low-Voltage Power Supply) When DC low voltage DL is supplied from low-voltage power supply 100 as shown in Fig. 7 from the state shown in Fig. 2, DC low voltage DL is input to low-voltage side drive circuit 32. Then, DC low voltage DL energizes drive system 31c of low-voltage side converter 31. Furthermore, input of DC low voltage DL to low-voltage side drive circuit 32 energizes coil 53c of low-voltage side second relay 53 and stores electricity in low-voltage side first capacitor 58.

[0048] As shown in FIG. 8 , when the coil 53c of the low-voltage side second relay 53 is energized, the switch 53s provided in the low-voltage side main circuit 33 is closed. Then, the DC low voltage DL from the low-voltage power supply 100 is input to the low-voltage side main circuit 33. The DC low voltage DL input to the low-voltage side main circuit 33 initially passes through the low-voltage side inrush resistor 56 and is input to the main system 31d of the low-voltage side converter 31. This suppresses the DC low voltage DL from inrush into the low-voltage side converter 31. The DC low voltage DL input to the low-voltage side converter 31 is boosted to the DC set voltage DS and supplied to the electric compressor 15 via the low-voltage side output circuit 34. This allows the refrigeration cycle system 10 to begin operating with the voltage supplied from the low-voltage power supply 100. At this time, when DC set voltage DS is output to low-voltage side output circuit 34, current is passed through coil 51c of high-voltage cut-off relay 51 and coil 52c of low-voltage side first relay 52.

[0049] 9, when coil 52c of low-voltage side first relay 52 is energized, switch 52s provided in low-voltage side main circuit 33 is closed. As a result, DC low voltage DL from low-voltage power supply 100 is input directly to low-voltage side converter 31 without passing through low-voltage side inrush resistor 56. As a result, DC low voltage DL, which had been suppressed by low-voltage side inrush resistor 56, returns to its original voltage. In addition, when coil 51c of high-voltage cut-off relay 51 is energized, high-voltage side drive circuit 42 and switch 51r of high-voltage cut-off relay 51 provided upstream of high-voltage side main circuit 43 are opened.

[0050] Subsequently, when the supply of DC low-voltage DL from low-voltage power supply 100 is stopped from the state shown in FIG. 9 , as shown in FIG. 10 , the input of DC low-voltage DL to low-voltage side drive circuit 32 and low-voltage side main circuit 33 and the output of DC set voltage DS from low-voltage side converter 31 are stopped. This causes current to flow through coil 52c of low-voltage side first relay 52, and switch 52s opens. At this time, the charges stored in low-voltage side first capacitor 58 and low-voltage side second capacitor 59 are released, maintaining voltage supply to coil 53c of low-voltage side second relay 53, drive system 31c of low-voltage side converter 31, and electric compressor 15 for a certain period of time. This causes switch 53s to remain closed. Furthermore, low-voltage side converter 31 prevents itself from stopping operation while main system 31d is energized. Furthermore, the power supply to coil 51c of high-voltage cutoff relay 51 is cut off, causing switch 51r of high-voltage cutoff relay 51 to close. After that, when discharge from low-voltage side first capacitor 58 is completed, power supply to coil 53c is cut off, switch 53s is opened, and the state returns to that shown in FIG.

[0051] (Voltage Supply from Low-Voltage Power Supply While Voltage is Being Supplied from High-Voltage Power Supply) As shown in FIG. 5 , when generator 21 is started to supplementarily charge battery 25, which is high-voltage power supply 200, while DC high voltage DH is input from high-voltage power supply 200 and DC set voltage DS converted by high-voltage-side converter 41 is output to electric compressor 15, DC low voltage DL is input from low-voltage power supply 100 to voltage conversion device 30 as shown in FIG. 11 . DC low voltage DL from low-voltage power supply 100 is input to low-voltage-side drive circuit 32. Then, DC low voltage DL energizes drive system 31c of low-voltage-side converter 31. Furthermore, input of DC low voltage DL to low-voltage-side drive circuit 32 energizes coil 53c of low-voltage-side second relay 53 and stores electricity in low-voltage-side first capacitor 58.

[0052] As shown in FIG. 12 , when the coil 53c of the low-voltage side second relay 53 is energized, the switch 53s provided in the low-voltage side main circuit 33 is closed. Then, the DC low voltage DL from the low-voltage power supply 100 is input to the low-voltage side main circuit 33. The DC low voltage DL input to the low-voltage side main circuit 33 initially passes through the low-voltage side inrush resistor 56 and is input to the main system 31d of the low-voltage side converter 31. This suppresses the DC low voltage DL from inrush into the low-voltage side converter 31. The DC low voltage DL input to the low-voltage side converter 31 is boosted to the DC set voltage DS and supplied to the electric compressor 15 via the low-voltage side output circuit 34. When the DC set voltage DS is output to the low-voltage side output circuit 34, the coil 51c of the high-voltage cut-off relay 51 and the coil 52c of the low-voltage side first relay 52 are energized.

[0053] As shown in FIG. 13 , when current is applied to coil 51c of high-voltage cut-off relay 51, switch 51r of high-voltage cut-off relay 51, which is provided upstream of high-voltage side drive circuit 42 and high-voltage side main circuit 43, opens. This cuts off the input circuit for high-voltage DC voltage DH from high-voltage power supply 200, terminating the input of high-voltage DC voltage DH to high-voltage side drive circuit 42 and high-voltage side main circuit 43 and the output of DC set voltage DS from high-voltage side converter 41. This then de-energizes coil 62c of high-voltage side first relay 62, causing switch 62s to open. Furthermore, in high-voltage side drive circuit 42, the charge stored in high-voltage side capacitor 68 is released, maintaining voltage supply to coil 63c of high-voltage side second relay 63 and drive system 41c of high-voltage side converter 41 for a certain period of time. This causes switch 63s to remain closed for the certain period of time. Furthermore, the high-voltage converter 41 is prevented from stopping operation while the main system 41d is energized.

[0054] Furthermore, when current is passed through coil 52c of low-voltage side first relay 52, switch 52s provided in low-voltage side main circuit 33 closes. As a result, low DC voltage DL from low-voltage power supply 100 is input directly to low-voltage side converter 31 without passing through low-voltage side inrush resistor 56. As a result, low DC voltage DL, which had been suppressed by low-voltage side inrush resistor 56, returns to its original voltage. Thereafter, when the release of the charge stored in high-voltage side capacitor 68 is completed, current is no longer passed through coil 63c of high-voltage side second relay 63, and switch 63s opens, as shown in FIG.

[0055] In this way, when the DC low voltage DL is input from the low-voltage power supply 100 while the DC high voltage DH from the high-voltage power supply 200 is outputting the DC set voltage DS to the electric compressor 15, the input of the DC high voltage DH from the high-voltage power supply 200 is cut off, and the output of the DC set voltage DS to the electric compressor 15 is switched to the DC low voltage DL from the low-voltage power supply 100. In other words, when the DC high voltage DH is input from the high-voltage power supply 200 and the DC low voltage DL is input from the low-voltage power supply 100 simultaneously, the DC low voltage DL from the low-voltage power supply 100 takes priority in the voltage supply to the electric compressor 15.

[0056] Subsequently, when the supply of DC low-voltage DL from low-voltage power supply 100 is stopped from the state shown in FIG. 14 , as shown in FIG. 15 , the input of DC low-voltage DL to low-voltage side drive circuit 32 and low-voltage side main circuit 33 and the output of DC set voltage DS from low-voltage side converter 31 are stopped. This causes current to flow through coil 52c of low-voltage side first relay 52, and switch 52s opens. At this time, the charges stored in low-voltage side first capacitor 58 and low-voltage side second capacitor 59 are released, maintaining voltage supply to coil 53c of low-voltage side second relay 53, drive system 31c of low-voltage side converter 31, and electric compressor 15 for a certain period of time. This causes switch 53s to remain closed. Furthermore, low-voltage side converter 31 prevents itself from stopping operation while main system 31d is energized.

[0057] Furthermore, as a result of the de-energization of coil 51c of high-voltage cut-off relay 51, switch 51r of high-voltage cut-off relay 51 changes from an open state to a closed state, as shown in FIG. 16 . This causes DC high voltage DH from high-voltage power supply 200 to be input to high-voltage side drive circuit 42. This DC high voltage DH energizes drive system 41c of high-voltage side converter 41. Furthermore, input of DC high voltage DH to high-voltage side drive circuit 42 energizes coil 63c of high-voltage side second relay 63 and charges high-voltage side capacitor 68. At this time, the voltage supply to electric compressor 15 is maintained for a certain period of time by discharging from low-voltage side second capacitor 59.

[0058] As shown in FIG. 17 , when the coil 63c of the high-voltage side second relay 63 is energized, the switch 63s provided in the high-voltage side main circuit 43 is closed. This causes the high DC voltage DH from the high-voltage power supply 200 to be input to the high-voltage side main circuit 43. The high DC voltage DH input to the high-voltage side main circuit 43 initially passes through the high-voltage side inrush resistor 66 and is input to the main system 41d of the high-voltage side converter 41. This suppresses the high DC voltage DH from inrush into the high-voltage side converter 41. The high DC voltage DH input to the high-voltage side converter 41 is stepped down to the DC set voltage DS and supplied to the electric compressor 15 via the high-voltage side output circuit 44. At this time, the DC set voltage DS is output to the high-voltage side output circuit 44, causing the coil 62c of the high-voltage side first relay 62 to be energized.

[0059] 18 , when the coil 62c of the first high-voltage side relay 62 is energized, the switch 62s provided in the high-voltage side main circuit 43 is closed. Then, the DC high voltage DH from the high-voltage power supply 200 is input directly to the high-voltage side converter 41 without passing through the high-voltage side inrush resistor 66. As a result, the DC high voltage DH that had been suppressed by the high-voltage side inrush resistor 66 returns to its original voltage. In this way, if the input of the DC low voltage DL from the low-voltage power supply 100 is stopped while the DC set voltage DS is being output to the electric compressor 15 by the DC low voltage DL from the low-voltage power supply 100, the output of the DC set voltage DS to the electric compressor 15 is switched to the DC high voltage DH from the high-voltage power supply 200.

[0060] (Voltage supply from high-voltage power supply while voltage is being supplied from low-voltage power supply) As shown in Fig. 9, when DC low voltage DL is input from low-voltage power supply 100 and the DC set voltage DS converted by low-voltage-side converter 31 is output to electric compressor 15, even if an attempt is made to input DC high voltage DH from battery 25, which is high-voltage power supply 200, as shown in Fig. 19, switch 51r of high-voltage cut-off relay 51 is in the open state. For this reason, when DC low voltage DL is input from low-voltage power supply 100 and the DC set voltage DS converted by low-voltage-side converter 31 is output to electric compressor 15, the input of DC high voltage DH from high-voltage power supply 200 is not accepted.

[0061] Furthermore, if the input of the DC high voltage DH from the battery 25, which is the high-voltage power supply 200, is stopped in the state shown in Figure 19, the switch 51r of the high-voltage cut-off relay 51 is in the open state, and the state returns to the state shown in Figure 9.

[0062] (Operation and Effect) In the voltage conversion device 30 configured as described above, the low-voltage-side converter 31 converts the low DC voltage DL input from the low-voltage power supply 100 into the set DC voltage DS. The high-voltage-side converter 41 converts the high DC voltage DH input from the high-voltage power supply 200 into the set DC voltage DS. The switching circuit unit 50 switches the voltage output state from the low-voltage-side converter 31 and the high-voltage-side converter 41 to the electric compressor 15 according to the voltage input states from the low-voltage power supply 100 and the high-voltage power supply 200. As a result, in a hybrid vehicle 1 using both an engine 22 and a motor (not shown), if the generator 21 driven by the engine 22 is the low-voltage power supply 100 and the battery 25 for the motor (not shown) is the high-voltage power supply 200, the voltage output state from the low-voltage-side converter 31 and the high-voltage-side converter 41 to the electric compressor 15 can be automatically switched according to the voltage input states from the low-voltage power supply 100 and the high-voltage power supply 200. As a result, the voltage conversion device 30 alone can convert the voltage output to the electric compressor 15 without being controlled by a vehicle controller (not shown) on the vehicle body 2. Therefore, even when the output of the engine 22 and the output of the motor (not shown) fluctuate depending on the running state of the vehicle 1, the voltage supply to the refrigeration cycle 12 can be performed efficiently and stably.

[0063] Furthermore, when the voltage conversion device 30 receives the low DC voltage DL only from the low-voltage power supply 100, it outputs the DC set voltage DS obtained by the low-voltage-side converter 31, and when the high DC voltage DH only from the high-voltage power supply 200, it outputs the DC set voltage DS obtained by the high-voltage-side converter 41. Furthermore, when the low DC voltage DL from the low-voltage power supply 100 and the high DC voltage DH from the high-voltage power supply 200 are input, the voltage conversion device 30 outputs the DC set voltage DS obtained by the low-voltage-side converter 31 and the DC set voltage DS obtained by the high-voltage-side converter 41 to the electric compressor 15. In this way, the voltage output states from the low-voltage-side converter 31 and the high-voltage-side converter 41 to the electric compressor 15 can be automatically switched depending on the voltage input states from the low-voltage power supply 100 and the high-voltage power supply 200.

[0064] Furthermore, in voltage conversion device 30, when DC set voltage DS is output to low-voltage side output circuit 34, high-voltage cut-off relay 51 cuts off high-voltage side drive circuit 42 and high-voltage side main circuit 43. As a result, when DC high voltage DH is input from high-voltage power supply 200 and DC low voltage DL is input from low-voltage power supply 100 simultaneously, the DC low voltage DL input from low-voltage power supply 100 can be given priority in the voltage supply to electric compressor 15.

[0065] Furthermore, in voltage conversion device 30, the operation of low-voltage side first relay 52, high-voltage side first relay 62, low-voltage side second relay 53, and high-voltage side second relay 63 can automatically switch the voltage output state from low-voltage side converter 31 and high-voltage side converter 41 to electric compressor 15 depending on the voltage input state from low-voltage power supply 100 and high-voltage power supply 200.

[0066] Furthermore, in voltage conversion device 30, low-voltage side diode 54 prevents DC set voltage DS from flowing back from high-voltage side output circuit 44 to low-voltage side converter 31. Furthermore, high-voltage side diode 64 prevents DC set voltage DS from flowing back from low-voltage side output circuit 34 to high-voltage side converter 41.

[0067] In addition, in the voltage conversion device 30, the low-voltage side inrush resistor 56 and the high-voltage side inrush resistor 66 prevent excessive voltage from rushing into the low-voltage side converter 31 and the high-voltage side converter 41 when the switch 52s of the low-voltage side first relay 52 and the switch 62s of the high-voltage side first relay 62 are connected.

[0068] In addition, in the voltage conversion device 30, the low-voltage side first capacitor 58 and the high-voltage side capacitor 68 can maintain the voltage supply to the drive system 31c of the low-voltage side converter 31 and the drive system 41c of the high-voltage side converter 41 for a certain period of time after the voltage supply to the main system 31d of the low-voltage side converter 31 and the main system 41d of the high-voltage side converter 41 has ended.

[0069] Furthermore, in the voltage conversion device 30, the low-voltage side second capacitor 59 can maintain the voltage supply from the low-voltage side output circuit 34 to the electric compressor 15 for a certain period of time.

[0070] Furthermore, in the voltage conversion device 30, when the DC set voltage DS is set higher than the DC low voltage DL and lower than the DC high voltage DH, the low DC voltage DL can be boosted to the DC set voltage DS higher than the DC low voltage DL by the boost converter serving as the low-voltage-side converter 31. Furthermore, the high-voltage-side converter 41 can be used to step down the DC high voltage DH to the DC set voltage DS lower than the DC high voltage DH.

[0071] In the refrigeration cycle system 10 configured as described above, it is possible to provide the refrigeration cycle system 10 including the voltage conversion device 30 that can supply voltage to the refrigeration cycle 12 efficiently and stably.

[0072] In the vehicle 1 configured as described above, it is possible to provide a vehicle 1 equipped with a voltage conversion device 30 that can supply voltage to the refrigeration cycle 12 efficiently and stably.

[0073] (Other Embodiments) While the embodiments of the present disclosure have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications and the like are also included within the scope of the gist of the present disclosure. Note that, although the circuit configuration of the switching circuit unit 50 has been described in the above embodiment, the configuration can be modified as appropriate as long as it can perform the same function. Furthermore, some of the functions of the switching circuit unit 50 may be omitted, and other functions may be added as appropriate.

[0074] In the above embodiment, the provision of the high-voltage cutoff relay 51 allows the input of the DC low voltage DL from the low-voltage power supply 100 to take priority when the input of the DC high voltage DH from the high-voltage power supply 200 and the input of the DC low voltage DL from the low-voltage power supply 100 are made simultaneously, but this is not limiting. For example, by providing a configuration similar to the high-voltage cutoff relay 51 in the low-voltage side circuit, it is also possible to give priority to the input of the DC high voltage DH from the high-voltage power supply 200.

[0075] <Additional Notes> The voltage conversion device 30, the refrigeration cycle system 10, and the vehicle 1 described in the embodiment can be understood, for example, as follows.

[0076] (1) A voltage conversion device 30 according to a first aspect converts voltages input from a low-voltage power supply 100 and a high-voltage power supply 200 into voltages appropriate for the electric compressor 15 of the refrigeration cycle 12 and outputs the converted voltages. The voltage conversion device 30 includes a low-voltage converter 31 that converts a low DC voltage DL input from the low-voltage power supply 100 into a predetermined DC set voltage DS to drive the electric compressor 15, a high-voltage converter 41 that converts a high DC voltage DH input from the high-voltage power supply 200 into the DC set voltage, and a switching circuit unit 50 that switches the voltage output state from the low-voltage converter 31 and the high-voltage converter 41 to the electric compressor 15 depending on the voltage input state from the low-voltage power supply 100 and the high-voltage power supply 200.

[0077] In this voltage conversion device 30, low-voltage-side converter 31 converts a low DC voltage DL input from low-voltage power supply 100 into a set DC voltage DS. High-voltage-side converter 41 converts a high DC voltage DH input from high-voltage power supply 200 into a set DC voltage DS. Switching circuit unit 50 switches the voltage output state from low-voltage-side converter 31 and high-voltage-side converter 41 to electric compressor 15 depending on the voltage input states from low-voltage power supply 100 and high-voltage power supply 200. As a result, in vehicle 1, which is a hybrid vehicle using both an engine 22 and a motor (not shown), if the generator 21 driven by the engine 22 is used as the low-voltage power supply 100 and the battery 25 for the motor (not shown) is used as the high-voltage power supply 200, the voltage output state from low-voltage-side converter 31 and high-voltage-side converter 41 to electric compressor 15 can be automatically switched depending on the voltage input states from low-voltage power supply 100 and high-voltage power supply 200. As a result, the voltage conversion device 30 alone can convert the voltage output to the electric compressor 15 without being controlled by a vehicle controller (not shown) on the vehicle body 2. Therefore, even when the output of the engine 22 and the output of the motor (not shown) fluctuate depending on the running state of the vehicle 1, the voltage supply to the refrigeration cycle 12 can be performed efficiently and stably.

[0078] (2) A voltage conversion device 30 according to a second aspect is the voltage conversion device 30 of (1), in which, when a low DC voltage DL is input only from the low-voltage power supply 100, the switching circuit unit 50 outputs the DC set voltage DS obtained by converting the low DC voltage DL in the low-voltage-side converter 31 to the electric compressor 15, and when a high DC voltage DH is input only from the high-voltage power supply 200, the switching circuit unit 50 converts the high DC voltage DH in the high-voltage-side converter 41 to The DC set voltage DS obtained by the conversion is output to the electric compressor 15, and when a low DC voltage DL from the low-voltage power supply 100 and a high DC voltage DH from the high-voltage power supply 200 are input, the DC set voltage DS obtained by converting the low DC voltage DL in the low-voltage side converter 31 and the DC set voltage DS obtained by converting the high DC voltage DH in the high-voltage side converter 41 are output to the electric compressor 15.

[0079] As a result, when the low DC voltage DL is input only from the low-voltage power supply 100, the DC set voltage DS obtained by the low-voltage-side converter 31 is output, and when the high DC voltage DH is input only from the high-voltage power supply 200, the DC set voltage DS obtained by the high-voltage-side converter 41 is output. Also, when the low DC voltage DL from the low-voltage power supply 100 and the high DC voltage DH from the high-voltage power supply 200 are input, the DC set voltage DS obtained by the low-voltage-side converter 31 and the DC set voltage DS obtained by the high-voltage-side converter 41 are output to the electric compressor 15. In this way, the voltage output states from the low-voltage-side converter 31 and the high-voltage-side converter 41 to the electric compressor 15 can be automatically switched depending on the voltage input states from the low-voltage power supply 100 and the high-voltage power supply 200.

[0080] (3) A voltage conversion device 30 according to a third aspect is the voltage conversion device 30 of (1) or (2), wherein the switching circuit unit 50 includes a low-voltage side drive circuit 32 that inputs the DC low voltage DL to a drive system 31c of the low-voltage side converter 31, a low-voltage side main circuit 33 that inputs the DC low voltage DL to a main system 31d of the low-voltage side converter 31, a low-voltage side output circuit 34 that outputs a DC set voltage DS output from the main system 31d of the low-voltage side converter 31 to the electric compressor 15, and The inverter comprises a high-voltage side drive circuit 42 that inputs the DC high voltage DH to a drive system 41c of a high-voltage side converter 41, a high-voltage side main circuit 43 that inputs the DC high voltage DH to a main system 41d of the high-voltage side converter 41, a high-voltage side output circuit 44 that outputs a DC set voltage DS output from the main system 41d of the high-voltage side converter 41 to the electric compressor 15, and a high-voltage cut-off relay 51 that cuts off the high-voltage side drive circuit 42 and the high-voltage side main circuit 43 when the DC set voltage DS is output to the low-voltage side output circuit 34.

[0081] As a result, when DC set voltage DS is output to low-voltage side output circuit 34, high-voltage cut-off relay 51 cuts off high-voltage side drive circuit 42 and high-voltage side main circuit 43. As a result, when DC low voltage DL is input only from low-voltage power supply 100, DC set voltage DS obtained by converting DC low voltage DL in low-voltage side converter 31 can be output to electric compressor 15.

[0082] (4) A voltage conversion device 30 according to a fourth aspect is the voltage conversion device 30 of (3), wherein the switching circuit unit 50 further includes a low-voltage side first relay 52 that inputs the DC low voltage DL to the low-voltage side main circuit 33 when the DC set voltage DS is output to the low-voltage side output circuit 34, a high-voltage side first relay 62 that inputs the DC high voltage DH to the high-voltage side main circuit 43 when the DC set voltage DS is output to the high-voltage side output circuit 44, a low-voltage side second relay 53 that inputs the DC low voltage DL to the low-voltage side main circuit 33 when the DC low voltage DL is input to the low-voltage side drive circuit 32, and a high-voltage side second relay 63 that inputs the DC high voltage DH to the high-voltage side main circuit 43 when the DC high voltage DH is input to the high-voltage side drive circuit 42.

[0083] As a result, by the operation of the low-voltage side first relay 52, the high-voltage side first relay 62, the low-voltage side second relay 53, and the high-voltage side second relay 63, the voltage output state from the low-voltage side converter 31 and the high-voltage side converter 41 to the electric compressor 15 can be automatically switched depending on the voltage input state from the low-voltage power supply 100 and the high-voltage power supply 200.

[0084] (5) A voltage conversion device 30 according to a fifth aspect is the voltage conversion device 30 of (3) or (4), wherein the switching circuit unit 50 further includes a low-voltage side diode 54 provided in the low-voltage side output circuit 34 and configured to output the DC set voltage DS from the low-voltage side converter 31 only to the electric compressor 15 side, and a high-voltage side diode 64 provided in the high-voltage side output circuit 44 and configured to output the DC set voltage DS from the high-voltage side converter 41 only to the electric compressor 15 side.

[0085] As a result, low-voltage side diode 54 prevents DC set voltage DS from flowing back from high-voltage side output circuit 44 to low-voltage side converter 31. In addition, high-voltage side diode 64 prevents DC set voltage DS from flowing back from low-voltage side output circuit 34 to high-voltage side converter 41.

[0086] (6) A sixth aspect of the voltage conversion device 30 is the voltage conversion device 30 of (3) or (5), wherein the switching circuit unit 50 further includes a low-voltage side inrush resistor 56 arranged in parallel with the switch 52s of the low-voltage side first relay 52 provided in the low-voltage side main circuit 33, and a high-voltage side inrush resistor 66 arranged in parallel with the switch 62s of the high-voltage side first relay 62 provided in the high-voltage side main circuit 43.

[0087] As a result, the low-voltage side inrush resistor 56 and the high-voltage side inrush resistor 66 prevent excessive voltage from rushing into the low-voltage side converter 31 and the high-voltage side converter 41 when the switch 52s of the low-voltage side first relay 52 and the switch 62s of the high-voltage side first relay 62 are connected.

[0088] (7) The voltage conversion device 30 according to the seventh aspect is any one of the voltage conversion devices 30 of (3) to (6), wherein the switching circuit unit 50 further includes a low-voltage side first capacitor 58 provided in the low-voltage side drive circuit 32 and a high-voltage side capacitor 68 provided in the high-voltage side drive circuit 42.

[0089] As a result, after the voltage supply to the main system 31d of the low-voltage side converter 31 and the main system 41d of the high-voltage side converter 41 has ended, the voltage supply to the drive system 31c of the low-voltage side converter 31 and the drive system 41c of the high-voltage side converter 41 can be maintained for a certain period of time by the low-voltage side first capacitor 58 and the high-voltage side capacitor 68.

[0090] (8) The voltage conversion device 30 according to the eighth aspect is any one of the voltage conversion devices 30 of (3) to (7), in which the switching circuit unit 50 further includes a low-voltage side second capacitor 59 provided in the low-voltage side output circuit 34.

[0091] As a result, the low-voltage side second capacitor 59 can maintain the voltage supply from the low-voltage side output circuit 34 to the electric compressor 15 for a certain period of time.

[0092] (9) The voltage conversion device 30 according to the ninth aspect is any one of the voltage conversion devices 30 of (1) to (8), in which the DC set voltage DS is set higher than the DC low voltage DL and lower than the DC high voltage DH, the low-voltage side converter 31 is a step-up converter, and the high-voltage side converter 41 is a step-down converter.

[0093] As a result, when the DC set voltage DS is set higher than the DC low voltage DL and lower than the DC high voltage DH, the boost converter serving as the low-voltage-side converter 31 can boost the DC low voltage DL to the DC set voltage DS, which is higher than the DC low voltage DL. Also, the high-voltage converter serving as the high-voltage-side converter 41 can step down the DC high voltage DH to the DC set voltage DS, which is lower than the DC high voltage DH.

[0094] (10) The refrigeration cycle system 10 according to the tenth aspect includes a voltage conversion device 30 selected from any one of (1) to (9) and a refrigeration cycle 12 having an electric compressor 15 driven by the DC set voltage DS output from the voltage conversion device 30.

[0095] This makes it possible to provide a refrigeration cycle system 10 including a voltage conversion device 30 that can supply voltage to the refrigeration cycle 12 efficiently and stably.

[0096] (11) A vehicle 1 according to an eleventh aspect includes a vehicle body 2 and the refrigeration cycle system 10 of (10) mounted on the vehicle body 2.

[0097] This makes it possible to provide a vehicle 1 equipped with a voltage conversion device 30 that can supply voltage to the refrigeration cycle 12 efficiently and stably.

[0098] According to each embodiment of the present disclosure, voltage can be supplied to a refrigeration cycle efficiently and stably.

[0099] DESCRIPTION OF SYMBOLS 1...Vehicle 2...Vehicle body 4...Chassis 4w...Wheels 5...Cabin 6...Container 7...Unit housing 10...Refrigeration cycle system 11...Container 12...Refrigeration cycle 13...Indoor heat exchanger 14...Outdoor heat exchanger 15...Electric compressor 21...Generator 22...Engine 25...Battery 30...Voltage conversion device 31...Low-voltage side converter 31c...Drive system 31d...Main system 32...Low-voltage side drive circuit 33...Low-voltage side main circuit 34...Low-voltage side output circuit 41...High-voltage side converter 41c...Drive system 41d...Main system 42...High-voltage side drive circuit 43...High-voltage side main circuit 44...High-voltage side output circuit 50...Switching circuit section 51...High-voltage cut-off relay 51c...Coil 51r...Switch 52...Low-voltage side first relay 52c...Coil 52s...Switch 53...Low-voltage side second relay 53c...Coil 53s...Switch 54...Low-voltage side diode 56...Low-voltage side inrush resistor 57...Diode 58...Low-voltage side first capacitor 59...Low-voltage side second capacitor 62...High-voltage side first relay 62c...Coil 62s...Switch 63...High-voltage side second relay 63c...Coil 63s...Switch 64...High-voltage side diode 66...High-voltage side inrush resistor 68...High-voltage side capacitor 100...Low-voltage power supply 200...High-voltage power supply DH...DC high voltage DL...DC low voltage DS...DC set voltage

Claims

1. A voltage conversion device that converts voltages input from a low-voltage power supply and a high-voltage power supply into voltages appropriate for an electric compressor of a refrigeration cycle and outputs the converted voltages, comprising: a low-voltage converter that converts the low DC voltage input from the low-voltage power supply into a preset DC set voltage to drive the electric compressor; a high-voltage converter that converts the high DC voltage input from the high-voltage power supply into the DC set voltage; and a switching circuit unit that switches the voltage output state from the low-voltage converter and the high-voltage converter to the electric compressor according to the voltage input state from the low-voltage power supply and the high-voltage power supply.

2. The voltage conversion device according to claim 1, wherein the switching circuit unit: when a low DC voltage is input only from the low-voltage power supply, outputs the DC set voltage obtained by converting the low DC voltage in the low-voltage side converter to the electric compressor; when a high DC voltage is input only from the high-voltage power supply, outputs the DC set voltage obtained by converting the high DC voltage in the high-voltage side converter to the electric compressor; and when a low DC voltage from the low-voltage power supply and a high DC voltage from the high-voltage power supply are input, outputs the DC set voltage obtained by converting the low DC voltage in the low-voltage side converter and the DC set voltage obtained by converting the high DC voltage in the high-voltage side converter to the electric compressor.

3. The voltage conversion device according to claim 1 or 2, wherein the switching circuit unit comprises: a low-voltage side drive circuit that inputs the DC low voltage to the drive system of the low-voltage side converter; a low-voltage side main circuit that inputs the DC low voltage to the main system of the low-voltage side converter; a low-voltage side output circuit that outputs a DC set voltage output from the main system of the low-voltage side converter to the electric compressor; a high-voltage side drive circuit that inputs the DC high voltage to the drive system of the high-voltage side converter; a high-voltage side main circuit that inputs the DC high voltage to the main system of the high-voltage side converter; a high-voltage side output circuit that outputs the DC set voltage output from the main system of the high-voltage side converter to the electric compressor; and a high-voltage cut-off relay that cuts off the high-voltage side drive circuit and the high-voltage side main circuit when the DC set voltage is output to the low-voltage side output circuit.

4. The voltage conversion device according to claim 3, wherein the switching circuit unit further comprises: a low-voltage side first relay that inputs the DC low voltage to the low-voltage side main circuit when the DC set voltage is output to the low-voltage side output circuit; a high-voltage side first relay that inputs the DC high voltage to the high-voltage side main circuit when the DC set voltage is output to the high-voltage side output circuit; a low-voltage side second relay that inputs the DC low voltage to the low-voltage side main circuit when the DC low voltage is input to the low-voltage side drive circuit; and a high-voltage side second relay that inputs the DC high voltage to the high-voltage side main circuit when the DC high voltage is input to the high-voltage side drive circuit.

5. The voltage conversion device according to claim 4, wherein the switching circuit section further comprises: a low-voltage side diode provided in the low-voltage side output circuit, for outputting a DC set voltage from the low-voltage side converter only to the electric compressor side; and a high-voltage side diode provided in the high-voltage side output circuit, for outputting a DC set voltage from the high-voltage side converter only to the electric compressor side.

6. The voltage conversion device according to claim 4, wherein the switching circuit section further comprises: a low-voltage side inrush resistor arranged in parallel with a switch of the low-voltage side first relay provided in the low-voltage side main circuit; and a high-voltage side inrush resistor arranged in parallel with a switch of the high-voltage side first relay provided in the high-voltage side main circuit.

7. The voltage conversion device according to claim 4, wherein the switching circuit section further comprises: a low-voltage side first capacitor provided in the low-voltage side drive circuit; and a high-voltage side capacitor provided in the high-voltage side drive circuit.

8. The voltage conversion device according to claim 4, wherein the switching circuit section further comprises a low-voltage side second capacitor provided in the low-voltage side output circuit.

9. The voltage conversion device according to claim 1 or 2, wherein the DC set voltage is set higher than the DC low voltage and lower than the DC high voltage, the low voltage side converter is a step-up converter, and the high voltage side converter is a step-down converter.

10. A refrigeration cycle system comprising: a voltage conversion device according to claim 1 or 2; and a refrigeration cycle having an electric compressor driven by the DC set voltage output from the voltage conversion device.

11. A vehicle comprising: a vehicle body; and the refrigeration cycle system according to claim 10 mounted on the vehicle body.

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