Vehicle power supply system

Abstract

By reducing the amount of information communicated between vehicle power supply units and determining whether to start or stop the vehicle power supply unit according to the load capacity used, power saving of the vehicle power supply system is achieved. [Solution] The vehicle power supply system comprises at least two vehicle power supply units connected in parallel to supply power to a load device, and a control unit provided in the vehicle power supply unit that transmits the output power status of the vehicle power supply unit to a control line, receives the output power status of other vehicle power supply units from the control line, and controls the operating state and idle state of each vehicle power supply unit based on the output power status of each vehicle power supply unit.

Description

Technical Field

[0001] Embodiments of the present invention relate to a vehicle power supply system in a railway vehicle.

Background Art

[0002] As a vehicle power supply system mounted on a vehicle, a method of connecting outputs of a plurality of vehicle power supply devices in parallel and supplying power to a load (hereinafter referred to as a "parallel system") is known. In this parallel system, the capacity of the vehicle power supply device is determined so that even when one vehicle power supply device stops, the remaining vehicle power supply devices can supply power to the entire load.

[0003] On the other hand, the vehicle power supply device can achieve higher power conversion efficiency and power saving effect when operating near the rated load capacity rather than operating in a low load state. Therefore, in a parallel system where the devices are in a sound state, the state where only the devices capable of covering the entire load operate during low load provides the most power saving effect.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional parallel system, the vehicle power supply devices are started or stopped based on the power consumption within the formation. For this purpose, communication is performed between the vehicle power supply devices at a predetermined cycle, and information such as the equipment type number, operating state, and output sharing capacity of each vehicle power supply device is shared with each other. After aggregating the information of all vehicle power supply devices including the own device, a start or stop of the vehicle power supply device or a load reduction command is output to the load device according to the total output capacity with respect to the total rated capacity.

[0006] In this way, by mutually sharing information such as equipment type number, operating status, and output capacity among the power supply units for each vehicle, efficient parallel operation can be achieved, and it also offers excellent expandability when equipping vehicle power supply units within a train set. However, because each vehicle's power supply unit needed to communicate at predetermined intervals and share multiple pieces of information with each other, it was necessary to construct a complex control system.

[0007] The present invention has been made in view of the above, and aims to achieve power saving by reducing the amount of information communicated between vehicle power supply units and determining whether to start or stop the vehicle power supply unit according to the load capacity used. [Means for solving the problem]

[0008] The vehicle power supply system of the embodiment includes at least two vehicle power supply units connected in parallel to supply power to a load device, and a control unit provided in the vehicle power supply unit that transmits the output power status of the vehicle power supply unit to a control line, receives the output power status of the other vehicle power supply unit from the control line, and controls the operating state and idle state of the vehicle power supply unit based on the output power status of each vehicle power supply unit. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a diagram showing the configuration of a vehicle power supply system according to the first embodiment. [Figure 2] Figure 2 is a flowchart illustrating the output control operation to the control line of the vehicle power supply unit according to the first embodiment. [Figure 3] Figure 3 is a flowchart illustrating the shutdown control operation of the vehicle power supply unit according to the first embodiment. [Figure 4] Figure 4 is a flowchart illustrating the startup control operation of the vehicle power supply unit according to the first embodiment. [Figure 5] Figure 5 is a diagram showing the configuration of a vehicle power supply system according to the second embodiment. [Figure 6] Figure 6 is a flowchart illustrating the operation of the startup control and load reduction control of the vehicle power supply unit in the second embodiment. [Modes for carrying out the invention]

[0010] The embodiments will be described below with reference to the drawings. Figure 1 is a diagram showing the configuration of a vehicle power supply system according to the first embodiment. The vehicle power supply system 100 comprises a vehicle power supply unit 10 (10a, 10b, ..., 10n), a load unit 7 (7a, 7b, ..., 7m), a power line 11, and a control line 12.

[0011] The vehicle power supply unit 10 converts the DC power supplied via the current collector 8 into AC power and supplies it to the load device 7. In this embodiment, the explanation is given using a configuration in which DC power is supplied via the current collector 8 as an example, but any configuration capable of supplying DC power is acceptable, and for example, power supplied from a power generation facility or power storage device mounted on the vehicle may be used.

[0012] The load device 7 is, for example, equipment such as lighting equipment or air conditioning equipment installed in an electric vehicle. The load device 7 may also be a brake compressor, for instance. Power lines 11 are connected in parallel to n vehicle power supply units 10 and m load devices 7, respectively, to supply and demand power. n vehicle power supply units 10 are connected in parallel to the control line 12, and signals are exchanged between them. The control line may be a single wire or it may be composed of multiple wires. When sending and receiving multiple signals on a single wire, communication is performed by combining periodic signals.

[0013] Next, the vehicle power supply unit 10a will be described. Note that vehicle power supply units 10b, ..., and 10n have the same configuration as vehicle power supply unit 10a, so a detailed explanation will be omitted. Furthermore, where necessary, the letters a, b, ..., and n are added to the end of the reference numerals of the components, corresponding to vehicle power supply units 10a, 10b, ..., and 10n, respectively.

[0014] The vehicle power supply device 10a includes a power conversion unit 1a, an output filter circuit 2a, an output current detector 3a, an output voltage detector 4a, and a control unit 5a. The power conversion unit 1a converts the DC power supplied from the power collection device 8 into AC power. The output filter circuit 2a removes the harmonic components included in the AC power output from the power conversion unit 1a.

[0015] The output current detector 3a detects the current value output from the vehicle power supply device 10a to the power line 11. The output current detector 3a inputs the detected current value to the control unit 5a. The output voltage detector 4a detects the voltage output from the power conversion unit 1a. The output voltage detector 4a inputs the detected voltage value to the control unit 5a.

[0016] The control unit 5a controls the vehicle power supply device 10a in an overall manner. The vehicle power supply device 10a is a voltage control type power converter, and control is performed so as to supply a predetermined voltage even when the capacity of the load device 7 increases or decreases. When the load capacity increases, the current flowing through the vehicle power supply device 10a increases, and when the load capacity decreases, the current flowing through the vehicle power supply device 10a decreases. The control unit 5a outputs a converter gate signal to the power conversion unit 1a. The control unit 5a performs signal input and output with respect to the control line 12.

[0017] Next, the signal output from the vehicle power supply device to the control line will be described. FIG. 2 is a flowchart for explaining the output control operation to the control line of the vehicle power supply device according to the first embodiment. The control unit 5a of the vehicle power supply device 10a calculates the output power of the power conversion unit 1a based on the output current detected by the output current detector 3a (S01).

[0018] The control unit 5a determines whether the calculated output power is less than the first threshold value α (S02). If it is determined that it is less than the first threshold value α, the output of the control line is set to low output (S03). If it is determined that the calculated output voltage is not less than the first threshold value α, it is determined whether the calculated output voltage is less than the second threshold value β (S04).

[0019] If it is determined that the output is less than the second threshold value β, the output of the control line is set to the normal output (S05). If it is determined that the output is not less than the second threshold value β, the output of the control line is set to the high output (S06).

[0020] In this way, the control unit 5a sets the low output to H when the output is low, sets the normal output to H when the output is in normal operation, and sets the high output to H when the output is high, according to the output of the power conversion unit 1a. When each output does not meet the conditions, L is set for all of them.

[0021] Next, the control for stopping the vehicle power supply device will be described. FIG. 3 is a flowchart for explaining the stop control operation of the vehicle power supply device according to the first embodiment. Here, a priority order for operating the vehicle power supply device is set. When the priority is high, the operation state is continued, and when the priority is low, it is stopped when the overall usage load capacity of the vehicle power supply system is low. That is, it is set to start from the vehicle power supply device with a high priority and stop from the vehicle power supply device with a low priority.

[0022] The control unit 5a of the vehicle power supply device 10a determines whether the signal input from the control line is a low output (S11). As a method for determining that the input signal is a low output, it is preferable to aggregate the outputs of each vehicle power supply device and set it to a low output when each output is a low output or in a stopped state.

[0023] If it is determined that the output is a low output, it is determined whether the output of the control line of its own device is a low output (S12). If it is determined that the output of the control line of its own device is a low output, it is determined whether it is the lowest rank among the vehicle power supply devices whose priority is in operation (S13).

[0024] When the device determines that it is in the lowest position, it sets the output of the control line to pause (S14), pauses the vehicle power supply unit 10a, and stops supplying power to the load device 7 (S15). If none of the conditions in steps S11, S12, or S13 are met, the vehicle power supply unit 10a continues to operate, and the process returns to the decision in step S11.

[0025] Next, we will describe the control for starting the vehicle's power supply unit. Figure 4 is a flowchart illustrating the startup control operation of the vehicle's power supply unit in the first embodiment. The control unit 5a of the vehicle power supply unit 10a determines whether the signal input from the control line is high output (S21). It is preferable that the method for determining the input signal to be high output involves aggregating the outputs of each vehicle power supply unit and setting the output to high when any of the outputs is high output.

[0026] If it is determined that the output is high, it is determined whether the device is in a dormant state (S22). If it is determined that the device is in a dormant state, it is determined that its priority is the highest among the dormant vehicle power supply devices (S23).

[0027] When the device determines that it is in the highest position, it starts the vehicle power supply unit 10a and begins supplying power to the load device 7 (S24), and sets the output of the control line to normal operation (S25). If none of the conditions in steps S21, S22, or S23 are met, the vehicle power supply unit 10a will remain in a dormant state, and the process will return to the judgment in step S21.

[0028] As described above, by exchanging signals between each vehicle's power supply unit via control lines and controlling them, when the load capacity of the vehicle's power supply system is low, the number of operating vehicle power supply units can be reduced, thereby improving the efficiency of the operating vehicle power supply units and achieving power savings. Conversely, when the load capacity of the vehicle's power supply system is high, increasing the number of operating vehicle power supply units can prevent the vehicle's power supply system from shutting down or failing due to overload.

[0029] Furthermore, in the above embodiment, each vehicle power supply unit periodically outputs normal operation and idle states to the control line. Therefore, this signal can be used for monitoring the status of the vehicle power supply unit. Moreover, if a high output state is continuously output, it can be detected and used for fault monitoring of the vehicle power supply unit. In this way, the status of the vehicle power supply unit can be monitored without increasing the number of signals transmitted and received.

[0030] Next, a second embodiment will be described. Figure 5 is a diagram showing the configuration of the vehicle power supply system according to the second embodiment. The same reference numerals are used for parts that are the same as in the first embodiment, and their detailed descriptions are omitted.

[0031] In Figure 5, the differences from the first embodiment are that the load device 7 is equipped with a controller 9, and the control line 13 connects the vehicle power supply unit and the load device 7, and the load reduction commands are exchanged. In other words, the second embodiment includes a configuration that reduces the load and prevents the vehicle power supply system from shutting down or failing when an overload condition is detected even when all vehicle power supply units are operating, by issuing a load reduction command to the load device 7 via the control line 13.

[0032] Next, we will describe the control for starting up and reducing the load on the vehicle's power supply unit. Figure 6 is a flowchart illustrating the operation of the vehicle's power supply unit startup control and load reduction control in the second embodiment. The control unit 5a of the vehicle power supply unit 10a determines whether the signal input from the control line is high output (S31).

[0033] If it is determined that the output is high, it is determined whether the device is in a dormant state (S32). If it is determined that the device is in a dormant state, it is determined that its priority is the highest among the dormant vehicle power supply units (S33).

[0034] If the device determines that it is in the highest position, it starts the vehicle power supply unit 10a and begins supplying power to the load device 7 (S34), sets the output of the control line to normal operation (S35), and sets the load reduction command for the control line to OFF (S36). If neither of the conditions in steps S31 and S33 is met, the load reduction command for the control line is set to OFF in step S36 and the process returns to the determination in step S31.

[0035] Furthermore, in step S32, if it is determined that the device is not in a dormant state, it is determined whether the device is in a high-output state (S41). If the device determines that it is in a high-output state, it is determined that its priority is the lowest among the operational vehicle power supply units (S42).

[0036] When the device determines that it is at its lowest position, it sets the load reduction command on the control line to ON. When the load reduction command is set to ON, the signal is sent to the load device via the control line. Upon receiving the load reduction command, the load device 7 is controlled by the controller 9 to reduce the load power. If neither of the conditions in steps S41 and S42 is met, the vehicle power supply unit 10a continues to operate, and the process returns to the decision in step S31.

[0037] As described above, by exchanging signals between each vehicle's power supply unit via control lines and controlling them, when the load capacity of the vehicle's power supply system is low, the number of operating vehicle power supply units can be reduced, thereby improving the efficiency of the operating vehicle power supply units and achieving power savings. Conversely, when the load capacity of the vehicle's power supply system is high, increasing the number of operating vehicle power supply units can prevent the vehicle's power supply system from shutting down or failing due to overload.

[0038] Furthermore, if an overload condition is detected while all vehicle power supply units are operating, a load reduction command can be issued to the load devices to reduce the load and prevent the vehicle power supply system from shutting down or failing.

[0039] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0040] 1. Power conversion unit 5. Control Unit 7...Load device 9. Controller 10. Vehicle power supply 12, 13... control lines

Claims

1. At least two vehicle power supply units connected in parallel to supply power to the load device, A vehicle power supply system comprising a control unit provided in the vehicle power supply unit, which transmits the output power status of the vehicle power supply unit to a control line, receives the output power status of other vehicle power supply units from the control line, and controls the operating state and idle state of each vehicle power supply unit based on the output power status of each vehicle power supply unit.

2. The vehicle power supply system according to claim 1, wherein the control unit has information regarding the priority order for starting up vehicle power supply units, and controls the vehicle power supply unit to shut down when the output state of the vehicle power supply unit is low output and the priority for starting up among the operating vehicle power supply units is low.

3. The vehicle power supply system according to claim 2, wherein the control unit transmits two states to the control line: a first level when the output state is low output, and a second level when the output state is not low output.

4. The vehicle power supply system according to claim 1, wherein the control unit has information regarding the priority order for starting up vehicle power supply units, and controls the vehicle power supply unit to start up when the output state of the vehicle power supply unit is high output and the priority for starting up among the idle vehicle power supply units is high.

5. The vehicle power supply system according to claim 4, wherein the control unit transmits two states to the control line: a first level when the output state is high output, and a second level when the output state is not high output.

6. The load device has a controller that reduces load power, The vehicle power supply system according to claim 4, wherein the control unit with the lowest activation priority among the vehicle power supply units outputs a load reduction command to the controller when the output state of the vehicle power supply unit is high output.

Images