Vehicle system

Abstract

To provide a vehicle system capable of maintaining driving when a malfunction occurs in one power supply system, and adjusting output torque between motors.SOLUTION: A vehicle system includes a plurality of AC motors, a plurality of first DC-AC converters, and a plurality of second DC-AC converters. The plurality of first DC-AC converters correspond to the plurality of AC motors, respectively, convert DC power supplied from the first DC power supply into AC power, and supply AC power to each of the plurality of AC motors. The plurality of second DC-AC converters correspond to the plurality of AC motors, respectively, convert DC power supplied from a second DC power supply different from the first DC power supply into AC power, and supply AC power to each of the plurality of AC motors.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present invention relates to a vehicle system. [Background technology]

[0002] A commonly known vehicle system is one in which one motor is connected through two DC-AC converters, each of which is connected to two independent power supply systems. In this type of drive system, the vehicle can still be driven even if one of the DC-AC converters malfunctions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-295720 A [Patent Document 2] JP 2013-132197 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, since there is only one motor, if a malfunction occurs in the orthogonal converter or in one of the power supply systems, it becomes difficult to adjust the output torque between the motors.

[0005] An object of the present invention is to provide a vehicle system that maintains drive when a malfunction occurs in one of the power supply systems and that is capable of adjusting the output torque between the motors. [Means for solving the problem]

[0006] A vehicle system according to an embodiment includes a plurality of AC motors, a plurality of first DC converters, and a plurality of second DC converters. The first DC converters correspond to the plurality of AC motors, respectively, and convert DC power supplied from a first DC power source into AC power, and supply the AC power to the plurality of AC motors. The second DC converters correspond to the plurality of AC motors, respectively, and convert DC power supplied from a second DC power source different from the first DC power source into AC power, and supply the AC power to the plurality of AC motors. [Brief description of the drawings]

[0007] [Figure 1] 1 is a block diagram showing a configuration of a vehicle system according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing an example of the configuration of a vehicle system according to a comparative example. [Diagram 3] FIG. 1 is a diagram showing a schematic diagram of the relationship between the motor output and the total output torque when one system fails. [Figure 4] FIG. 11 is a diagram showing an example of the configuration of a portion of a vehicle system according to a second embodiment. [Diagram 5] FIG. 11 is a diagram showing an example of the configuration of a portion of a vehicle system according to a third embodiment. [Figure 6] FIG. 13 is a diagram showing an example of operation when a failure occurs in an inverter. [Figure 7] FIG. 13 is a diagram showing an example in which an inverter and a converter are configured as conversion elements of a two-level circuit system. [Figure 8] FIG. 13 is a diagram showing an example in which an inverter and a converter are configured as conversion elements of a three-level circuit system. [Figure 9] Block diagram of DC voltage control of the converter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a vehicle system according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the embodiment described below is an example of an embodiment of the present invention, and the present invention is not limited to these embodiments. In addition, in the drawings referred to in this embodiment, the same parts or parts having similar functions are given the same or similar symbols, and repeated explanations thereof may be omitted. Also, the dimensional ratios of the drawings may differ from the actual ratios for the convenience of explanation, and some components may be omitted from the drawings.

[0009] (First embodiment) Fig. 1 is a block diagram showing a configuration of a vehicle system 1 according to a first embodiment. As shown in Fig. 1, the vehicle system 1 is a system that can be mounted on, for example, a railway vehicle, and includes a first power supply system 2a, a second power supply system 2b, an AC power supply 10, a plurality of motors 40-45, and a control unit 50. Note that, although the vehicle system 1 according to this embodiment will be described as having two power supply systems 2a and 2b, this is not limiting. For example, the vehicle system 1 according to this embodiment can have three or more power supply systems.

[0010] The first power supply series 2a is a power supply series that supplies power to the multiple motors 40 to 45. The second power supply series 2b has the same configuration as the first power supply series 2a, and is a power supply series that supplies power to the multiple motors 40 to 45 independently of the first power supply series 2a.

[0011] The AC power supply 10 is, for example, a generator that generates AC power using power output by an engine, and outputs, for example, three-phase AC power.

[0012] Each of the motors 40-45 is a multiple winding motor, for example a two-winding motor. Each of the motors 40-45 can be a vehicle drive motor. Each of the motors 40-45 is supplied with three-phase AC power from a first power supply series 2a and a second power supply series 2b. For example, a first winding of a two-winding motor is supplied with three-phase AC power from the first power supply series 2a, and a second winding of the two-winding motor is supplied with three-phase AC power from the second power supply series 2b.

[0013] The first power supply system 2a includes a converter 20a and a plurality of inverters 30a to 35a. The converter 20a is supplied with AC power from an AC power supply 10. The converter 20a converts the AC power into DC power having a predetermined DC voltage, for example, by operating an internal switch under the control of the control unit 50. The converted DC power is supplied to each of the plurality of inverters 30a to 35. The converter 20a according to this embodiment corresponds to the first DC power supply, and the converter 20b corresponds to the second DC power supply.

[0014] The inverters 30a-35a each have the same configuration. These inverters 30a-35a are connected in parallel to the converter 20a. The inverters 30a-35a convert DC power into three-phase AC power having an arbitrary voltage and an arbitrary frequency, for example, by arbitrarily turning on (ON) or blocking (OFF) the switching elements according to the control of the control unit 50. Each of the inverters 30a-35a supplies three-phase AC power to each of the corresponding motors 40-45. For example, the inverter 30a supplies three-phase AC power to the motor 40, the inverter 31a supplies three-phase AC power to the motor 41, the inverter 32a supplies three-phase AC power to the motor 42, the inverter 33a supplies three-phase AC power to the motor 43, the inverter 34a supplies three-phase AC power to the motor 44, and the inverter 35a supplies three-phase AC power to the motor 45. The total number of inverters 30a to 35a and 30b to 35b is, but is not limited to, 12. The inverters 30a to 35a according to this embodiment correspond to a plurality of first orthogonal converters, and the inverters 30b to 35b correspond to a plurality of second orthogonal converters.

[0015] The second power supply system 2b includes a converter 20b and a plurality of inverters 30b to 35b. As described above, the second power supply system 2b has the same configuration as the first power supply system 2a. The converter 20b is capable of converting AC power into DC power of a predetermined DC voltage in synchronization with the converter 20a under the control of the control unit 50.

[0016] Each of the inverters 30b-35b supplies three-phase AC power to each of the corresponding motors 40-45 under the control of the control unit 50. For example, the inverter 30b supplies three-phase AC power to the motor 40, the inverter 31b supplies three-phase AC power to the motor 41, the inverter 32b supplies three-phase AC power to the motor 42, the inverter 33b supplies three-phase AC power to the motor 43, the inverter 34b supplies three-phase AC power to the motor 44, and the inverter 35b supplies three-phase AC power to the motor 45. In this manner, each of the motors 40-45 is driven by two converters 20a and 20b. Then, one converter 20a supplies power to every six of the inverters 30a-35a, and one converter 20b supplies power to every six of the inverters 30b-35b.

[0017] The control unit 50 comprehensively controls each unit in the vehicle system 1. The control unit 50 functions by, for example, a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit (not shown). Note that the control unit 50 may be a calculation means such as a microprocessor, a microcomputer, or a DSP (Digital Signal Processor).

[0018] The control unit 50 generates control signals for controlling the operations of the first power supply system 2a and the second power supply system 2b based on instructions input from a higher-level control device, for example. That is, the control unit 50 can generate control signals for controlling the operations of the converters 20a, 20b and the inverters 30a-35a, 30b-35b, and output them to the respective drivers.

[0019] The vehicle system 1 has redundancy against failures of the converters 20a, 20b and the inverters 30a-35a, 30b-35b. Even if a failure occurs in either the first power supply system 2a or the second power supply system 2b, it is possible to drive all the motors. In other words, even if one of the multiple inverters 30a-35a and the multiple inverters 30b-35b connected to one motor malfunctions, it is possible to drive the motors 40-45.

[0020] Furthermore, since the first power supply system 2a has a plurality of inverters 30a-35a and the second power supply system 2b has a plurality of inverters 30b-35b, even if one of the plurality of inverters 30a-35a malfunctions, it is possible to equalize the torque of each of the plurality of motors 40-45 by increasing the output of the inverter that is not malfunctioning among the plurality of inverters 30b-35b more than the remaining inverters.

[0021] Furthermore, even if one of the converters 20a, 20b malfunctions, the other power supply system can drive the multiple motors 40-45. In this case, since the first power supply system 2a and the second power supply system 2b have the same configuration, it is possible to output, for example, 50% of the maximum torque.

[0022] Generally, the tread output in a vehicle system depends on the friction coefficient between the rail and the wheels. For this reason, there are limited situations in which the motors 40 to 45 can output 100% of the maximum torque. In particular, the maximum torque cannot be output during acceleration or deceleration in rainy weather or other conditions where the road surface is slippery (the maximum static friction coefficient is small). In this situation, if it is not possible to output, for example, 50 percent or more of the maximum torque, the first power supply system 2a and the second power supply system 2b in the present invention have the same configuration, so that operation equivalent to normal operation (without failure) is possible.

[0023] Fig. 2 is a diagram showing an example of the configuration of a vehicle system 1a according to a comparative example. The same components as those in Fig. 1 are given the same reference numbers and will not be described. The vehicle system 1 according to the comparative example differs from the vehicle system 1 according to the present embodiment in that motors 80-82 and 83-85 to be driven are connected to each of two power supply series 3a and 3b. That is, in the vehicle system 1a according to the comparative example, the first power supply series 3a drives the motors 80-82, and the second power supply series 3b drives the motors 83-85. The motors 80-85 are, for example, permanent magnet motors.

[0024] The first power supply system 3a includes inverters 30a to 32a. The inverter 30a supplies three-phase AC power to the motor 80, the inverter 31a supplies three-phase AC power to the motor 81, and the inverter 32a supplies three-phase AC power to the motor .

[0025] The second power supply system 3b has inverters 30b to 32b. The inverter 30b supplies three-phase AC power to the motor 83, the inverter 31b supplies three-phase AC power to the motor 84, and the inverter 32b supplies three-phase AC power to the motor 85.

[0026] In the vehicle system 1a, even if a failure occurs in either the first power supply system 3a or the second power supply system 3b, it is possible to drive half of the motors. Therefore, it is common to the vehicle system 1 in that, even if a failure occurs, it is possible to drive, for example, a train. On the other hand, it is different in that, when one of the converters 20a, 20b fails, the vehicle system 1 according to the present embodiment can drive all six motors 40-42 and motors 43-45, whereas the vehicle system 1a according to the comparative example can only drive three motors 80-82 or motors 83-85.

[0027] FIG. 3 is a diagram showing a schematic diagram of the relationship between the output of one motor and the total output torque when one of the power supply systems fails. In FIG. 3, an example will be described in which the converter 20a of the first power supply system 2a according to the present embodiment and the converter 20a of the first power supply system 3a according to the comparative example each fail. The same applies to an example in which the converter 20b of the second power supply system 2b according to the present embodiment and the converter 20b of the second power supply system 3b according to the comparative example each fail. The horizontal axis indicates the tread output torque (motor torque) of one motor, and the vertical axis indicates the total output torque obtained by adding up all the motor outputs. Here, an example will be described in which the maximum static friction coefficient becomes small and the torque that can be output to the tread is restricted to 50% of the motor torque. The maximum torque of one motor is indicated by 100 percent, and the maximum value of the total output torque for each of the vehicle systems 1 and 1a is indicated by 50 percent. The maximum torque of the total output torque is indicated as the total output torque O1, and 25 percent of the total output torque is indicated as the total output torque O1a. Line L1 shows the relationship between the output torque of one motor of vehicle system 1 and the total output torque, and line L1a shows the relationship between the output torque of one motor of vehicle system 1a and the total output torque. For ease of explanation, it is assumed here that the input / output characteristics of each of motors 40-45 and each of motors 80-85 are equivalent.

[0028] In the vehicle system 1 according to this embodiment, when the first power supply system 2a and the second power supply system 2b are operating normally and the converters 20a and 20b are outputting 100% of the power, the output torque of each of the motors 40-45 is 100%. For ease of explanation, the input / output characteristics of the motors are assumed to be linear. Therefore, in the case where the converter 20a fails, the total output torque is assumed to be O1, and the total output torque at that time is assumed to be 50%.

[0029] Thus, in the vehicle system 1 according to this embodiment, if the first power supply system 2a fails, for example, even if the converter 20b outputs 100%, the output torque of each of the motors 40-45 will be limited to 50% of the motor torque because the maximum static friction coefficient will be small as described above. In other words, in the vehicle system 1 according to this embodiment, even if one of the power supply systems fails, if the output torque of each motor is limited to less than 50%, it is possible to maintain a total output torque equivalent to that of normal operation.

[0030] On the other hand, in the vehicle system 1a according to the comparative example, if the first power supply series 3a fails, only half of the vehicle system 1, that is, three motors, can be driven. Therefore, when the output torque of each of the motors 83-85 is limited to 50 percent or less, the total output torque O1a of the motors 83-85 corresponds to 50 percent of the total output torque O1. In this way, when the output torque of each of the motors is limited to less than 50 percent, the total output torque of the motors 40-42 and motors 43-45 of the vehicle system 1 according to the present embodiment becomes twice the total output torque of the vehicle system 1a according to the comparative example.

[0031] As shown in FIG. 3, if the maximum static friction coefficient becomes large and the output torque of each motor exceeds 50%, the total output torque O1 is maintained at 50% in the vehicle system 1 according to the present embodiment. In this case, in the vehicle system 1a according to the comparative example, as the torque that can be outputted per motor 83-85 exceeds 50%, the total output torque of the vehicle system 1a approaches the total output torque of the vehicle system 1. When the road surface output torque that can be outputted per motor 83-85 becomes 100%, the total output torque of the vehicle system 1a according to the comparative example becomes the same as that of the vehicle system 1 according to the present embodiment. As can be seen from these, in the vehicle system 1 according to the present embodiment, power is supplied from the first power supply series 2a and the second power supply series 2b to two or more motors 40-45, so that the total output is higher than that of the vehicle system 1a according to the comparative example in situations other than when the torque that can be outputted per motor 83-85 becomes 100%. In addition, when the first power supply system 2a and the second power supply system 2b supply power to a single motor, the difference in total output torque cannot be obtained. In other words, when two or more motors are connected to the first power supply system 2a and the second power supply system 2b, if one of the power supply systems fails, it is possible to obtain a total output torque greater than that of the comparative example.

[0032] This tendency is maintained even when the input and output of the motor is nonlinear. When the input power to the motor is suppressed to 50 percent or less, the total output torque of the vehicle system 1 capable of driving twice the motor is twice the total output torque of the vehicle system 1a. On the other hand, when the input power to the motor is allowed to exceed 50 percent, the total output torque of the vehicle system 1a approaches the total output torque of the vehicle system 1. However, when the input and output of the motor are nonlinear, the increase rate of the motor output torque is generally lower than the increase rate of the input power to the motor. Therefore, even when the input power to the motor becomes 100 percent, the total output torque of the vehicle system 1 according to this embodiment tends to be larger than the total output torque of the vehicle system 1a according to the comparative example.

[0033] As described above, according to the present embodiment, the vehicle system 1 drives each of the multiple motors 40-45 with power supplied from two corresponding inverters, the first power supply system 2a having the multiple inverters 30a-35a and the second power supply system 2b having the multiple inverters 30b-35b. This makes it possible to drive the multiple motors 40-45 even if one of the inverters 30a-35a and the inverters 30b-35b connected to one motor malfunctions. Also, it makes it possible to drive the motors 40-45 even if one of the first power supply system 2a and the second power supply system 2b malfunctions. In this case, two or more motors 40-45 are connected to the first power supply system 2a and the second power supply system 2b, and power is supplied to each of the motors 40-45 from the two power supply systems 2a and 2b. Therefore, when the number of motors is the same, the total output torque can be made larger than when power is supplied to different motors 80-85 for each of the two power supply systems 3a and 3b. Furthermore, since two or more motors 40-45 are connected to the first power supply system 2a and the second power supply system 2b, even if one of the inverters 30a-35a and the inverters 30b-35b malfunctions, the motors 40-45 can be driven evenly by adjusting the output of the other inverters.

[0034] Second embodiment The vehicle system 1 according to the second embodiment differs from the vehicle system 1 according to the first embodiment in that at least a portion of the systems between the first power supply system 2a and the second power supply system 2b is electrically insulated. The differences from the vehicle system 1 according to the first embodiment will be described below.

[0035] FIG. 4 is a diagram showing a configuration example of a part of the vehicle system 1 according to the second embodiment. As shown in FIG. 4, the first power supply system 2a and the second power supply system 2b are electrically insulated from each other. The first control unit 52a is a control unit of the converter 20a, and the second control unit 52b is a control unit of the converter 20b. The control units 52a and 52b function by, for example, a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit (not shown). The first control unit 52a controls the voltage of the converter 20a to a predetermined voltage according to a first voltage command value supplied from a higher-level control device or the like. Similarly, the second control unit 52b controls the voltage of the converter 20b to a predetermined voltage according to a second voltage command value that commands a voltage equal to the first voltage command value supplied from a higher-level control device or the like. The control units 52a and 52b may be calculation means such as a microprocessor, a microcomputer, or a DSP (Digital Signal Processor). As described above, the systems are electrically insulated from each other, and only the carrier synchronization signal between the control units 52a and 52b is transmitted, for example, optically. The carrier synchronization signal is used to suppress circulating current in the carrier frequency band.

[0036] The control power supply 60a supplies power to the first control unit 52a, and the control power supply 60b supplies power to the second control unit 52b. The control power supplies 60a, 60b can be supplied with power from a separate winding of the AC power supply 10. Alternatively, the control power supplies 60a, 60b may be supplied with power from the DC voltage of the converters 20a, 20b or from a separate power supply system.

[0037] As described above, each of the converters 20a, 20b can convert the AC power of the AC power source 10 into DC power corresponding to the conversion power of the inverter by controlling the AC power to a predetermined DC voltage according to the control of the control units 52a, 52b. Therefore, since the basic control between the converters 20a, 20b does not need to be coordinated, communication between the control units 52a, 52b is basically unnecessary.

[0038] Inter-converter communication between converters 20a and 20b may be provided or may be omitted. When inter-converter communication is provided, control units 52a and 52b may be integrated into one unit for common use. Converters 20a and 20b do not need to be electrically insulated from each other, but this increases the risk of simultaneous destruction in the event of a breakdown.

[0039] As described above, in the vehicle system 1 according to this embodiment, the first power supply system 2a and the second power supply system 2b are electrically insulated from each other. This makes it possible to suppress the influence of a fault such as a leakage current on one of the first power supply system 2a and the second power supply system 2b on the other.

[0040] Third embodiment The vehicle system 1 according to the third embodiment differs from the vehicle system 1 according to the first embodiment in that at least the inverters 30a-35a and the inverters 31b-35b between the first power supply system 2a and the second power supply system 2b are electrically insulated from each other. The differences from the vehicle system 1 according to the first embodiment will be described below.

[0041] Fig. 5 is a diagram showing an example of the configuration of a portion of a vehicle system 1 according to the third embodiment. Two inverters 30a, 30b are connected to one motor 40, and a third control unit 54 and a control power supply 62 are connected to the two inverters 30a, 30b. Although Fig. 5 shows only the motor 40, a similar control unit 54 and a control power supply 62 are connected to each of the inverters 31a-35a and 31b-35b that are pairs of motors 41-45.

[0042] The third control unit 54 controls the inverters 30a and 30b. The third control unit 54 functions by, for example, a processor such as a CPU (Central Processing Unit) executing a program stored in a storage unit (not shown). The third control unit 54 may be a calculation means such as a microprocessor, a microcomputer, or a DSP (Digital Signal Processor).

[0043] Since the inverters 30a, 30b are insulated from each other, communication between the third control unit 54 and the inverters 30a, 30b is also insulated. The third control unit 54 is supplied with power from a control power supply 62. The control power supply 62 can be supplied with power from a separate winding of the AC power supply 10. Alternatively, the control power supply 62 may be supplied with power from the DC voltage of the converters 20a, 20b or from a separate power supply system.

[0044] As described above, the vehicle system 1 according to this embodiment electrically insulates at least the inverters 30a-35a and the inverters 31b-35b between the first power supply system 2a and the second power supply system 2b. This makes it possible to suppress the influence on the other inverter even if a fault such as a leakage current occurs in one of the inverters in the first power supply system 2a and the second power supply system 2b.

[0045] (Fourth embodiment) The vehicle system 1 according to the fourth embodiment differs from the vehicle system 1 according to the first embodiment in that, when any of the inverters 30a-35a of the first power supply system 2a and the inverters 30b-35b of the second power supply system 2b malfunctions, the output between the converters 20a and 20b is controlled to be equal. The differences from the vehicle system 1 according to the first embodiment will be described below.

[0046] Fig. 6 is a diagram showing an example of operation when an inverter fails. As shown in Fig. 6, an example will be described in which the inverter 30a of the first power supply system 2a is malfunctioning and the inverters 30b and 31b of the second power supply system 2b are malfunctioning.

[0047] The control unit 50 controls the output ratio of each inverter when the power supply system is divided into a first power supply system 2a with a small number of failures and a second power supply system 2b with a large number of failures. When the number of motors is N (an integer), the number of failures of the inverters in the first power supply system 2a (system 1) is X1 (an integer), and the number of failures of the inverters in the second power supply system 2b (system 2) is X2 (an integer), the control unit 50 sets the ratio of the output of one inverter in the first power supply system 2a to the output of one inverter in the second power supply system 2b as N-X2:N-X1. This makes it possible to equalize the output between the converters 20a and 20b in the first power supply system 2a (system 1) and the second power supply system 2b (system 2). In this way, the converters in the first power supply system 2a and the second power supply system 2b are in the same operating state, so that the converters can be brought into an operating state in which they do not need to cooperate in basic control between the converters. In addition, it is also possible to equalize the device life span of the converters 20a and 20b, and the timing of replacement can be brought closer together.

[0048] Fifth embodiment Vehicle system 1 according to the fifth embodiment differs from vehicle system 1 according to the first embodiment in that inverters 30a-35a, inverters 30b-35b, and converters 20a, 20b are configured as converters and inverters of a two-level circuit system. The differences from vehicle system 1 according to the first embodiment will be described below.

[0049] Fig. 7 is a diagram showing an example in which inverters and converters are configured as conversion elements of a two-level circuit system. As shown in Fig. 7, the conversion elements constituting the inverters 30a-35a, inverters 30b-35b, and converters 20a and 20b include three pairs of switching elements Q1 and Q2 and a capacitor C10. Each of the switching elements Q1 and Q2 has a transistor and an anti-parallel diode. The transistor is, for example, a metal oxide semiconductor field effect transistor (MOSFET).

[0050] Three pairs of switching elements Q1 and Q2 connected in series are connected in parallel between terminals T1 and T2. Three-phase terminals U, V, and W are formed at each connection node of the three pairs of switching elements Q1 and Q2 connected in series. In addition, a capacitor C10 is connected between terminals T1 and T2. The voltage across the capacitor C10 is a DC voltage Vdc.

[0051] When configured as converters 20a and 20b, three-phase terminals u, v, and w of AC power source 10 are connected to three-phase terminals U, V, and W, and inverters 30a to 35a or inverters 30b to 35b are connected to terminals T1 and T2.

[0052] When configured as inverters 30a to 35a and inverters 30b to 35b, three-phase terminals u, v, and w of any of motors 40 to 45 are connected to three-phase terminals U, V, and W, and converter 20a or converter 20b is connected to terminals T1 and T2.

[0053] The control unit 50 controls the turn-on and turn-off of the three sets of serially connected switching elements Q1 and Q2. That is, the control unit 50 controls the gate current of the transistor by a gate signal. This controls the switching operation of the three sets of serially connected switching elements Q1 and Q2.

[0054] As described above, in the vehicle system 1 according to this embodiment, the inverters 30a-35a, the inverters 30b-35b, and the converters 20a, 20b are configured as converters and inverters of a two-level circuit system, which enables more efficient AC / DC conversion.

[0055] Sixth embodiment Vehicle system 1 according to the sixth embodiment differs from vehicle system 1 according to the first embodiment in that inverters 30a-35a, inverters 30b-35b, and converters 20a, 20b are configured as converters and inverters of a three-level circuit system. The differences from vehicle system 1 according to the first embodiment will be described below.

[0056] Fig. 8 is a diagram showing an example in which inverters and converters are configured as conversion elements of a three-level circuit system. As shown in Fig. 8, the conversion elements constituting inverters 30a-35a, inverters 30b-35b, and converters 20a and 20b include three layers of switching elements Qa-Qc and capacitors C20 and C30.

[0057] One end of each of the switching elements Qa to Qc is connected to the terminal T1, and the other end is connected to the terminal T2. Each of the switching elements Qa to Qc has a diode D1, D2 connected in series with the switching elements Q3 to Q6 connected in series. Each of the switching elements Q3 to Q6 has a transistor and an anti-parallel diode. The transistor is, for example, a metal oxide semiconductor field effect transistor (MOSFET). One end of the series-connected diodes D1, D2 is connected to the connection node of the switching elements Q3, Q4 and the connection node of the switching elements Q5, Q6.

[0058] The U terminal of switching element Qa is connected to the node connecting switching elements Q4 and Q5. Similarly, the V terminal of switching element Qb is connected to the node connecting switching elements Q4 and Q5. Similarly, the W terminal of switching element Qc is connected to the node connecting switching elements Q4 and Q5.

[0059] The capacitor C20 is connected between the terminal T2 and the terminal O. The capacitor C30 is connected between the terminal O and the terminal T1. The voltage across the capacitor C20 is the N-side voltage Vndc. The voltage across the capacitor C30 is the P-side voltage Vpdc.

[0060] When configured as converters 20a and 20b, three-phase terminals u, v, and w of AC power source 10 are connected to three-phase terminals U, V, and W, and inverters 30a to 35a or inverters 30b to 35b are connected to terminals T1 and T2.

[0061] When configured as inverters 30a to 35a and inverters 30b to 35b, three-phase terminals u, v, and w of any of motors 40 to 45 are connected to three-phase terminals U, V, and W, and converter 20a or converter 20b is connected to terminals T1 and T2.

[0062] The control unit 50 controls the turn-on and turn-off of the switching elements Q3 to Q6 of the switching elements Qa to Qc. That is, the control unit 50 controls the gate current of the transistor by a gate signal. This controls the switching operation of each of the three sets of switching elements Qa to Qc connected in series. Note that the circuits of the inverters 30a to 35a, the inverters 30b to 35b, and the converters 20a and 20b are not limited to these, and may be flying capacitor circuits or MMC circuits. Also, they are not limited to voltage type, and may be current type.

[0063] As described above, in the vehicle system 1 according to this embodiment, the inverters 30a-35a, the inverters 30b-35b, and the converters 20a, 20b are configured as converters and inverters of a three-level circuit system, thereby enabling more efficient AC / DC conversion.

[0064] Seventh embodiment Vehicle system 1 according to the seventh embodiment differs from vehicle system 1 according to the first embodiment in that it performs feedback control of the output voltages of converters 20a, 20b. The differences from vehicle system 1 according to the first embodiment will be described below.

[0065] Fig. 9 is a DC voltage control block diagram of the converter. As shown in Fig. 9, the control unit 50 has a first control unit 52a and a second control unit 52b. As shown in Fig. 4, the first control unit 52a and the second control unit 52b can be arranged separately for each system of the first power supply system 2a and the second power supply system 2b.

[0066] The first control unit 52a includes a first difference calculation unit 520a, an automatic voltage control unit (AVR) 521a, a second difference calculation unit 522a, an automatic current control unit (ACR) 523a, and a PWM signal generation unit 524a. The first difference calculation unit 520a calculates a difference between a DC voltage detection value, which is a measured value of the output voltage of the converter 20a, and a DC voltage command value, which is a command value from a higher-level control device. The automatic voltage control unit (AVR) 522a outputs a first command signal to the second difference calculation unit 522a based on the difference value calculated by the first difference calculation unit 520a so as to reduce the difference value.

[0067] The second difference calculation unit 522a calculates a difference between the AC current detection value, which is a measurement value on the input side of the converter 20a, and the first command signal. The automatic current control unit (ACR) 523a outputs a second command signal to the PWM signal generation unit 524a based on the difference value calculated by the second difference calculation unit 522a. The PWM signal generation unit 524a generates a PWM signal as a gate signal based on the second command signal and outputs it to the converter 20a.

[0068] The second control unit 52b has the same configuration as the first control unit 52a. That is, the first control unit 52b has a first difference calculation unit 520b, an automatic voltage control unit (AVR) 521b, a second difference calculation unit 522b, an automatic current control unit (ACR) 523b, and a PWM signal generation unit 524b. The first difference calculation unit 520b calculates a difference value between a DC voltage detection value, which is a measured value of the output voltage of the converter 20b, and a DC voltage command value, which is a command value from a higher-level control device. The automatic voltage control unit (AVR) 522b outputs a first command signal to the second difference calculation unit 522b based on the difference value calculated by the first difference calculation unit 520b so as to reduce the difference value.

[0069] The second difference calculation unit 522b calculates a difference between the AC current detection value, which is a measurement value on the input side of the converter 20b, and the first command signal. The automatic current control unit (ACR) 523b outputs a second command signal to the PWM signal generation unit 524b based on the difference value calculated by the second difference calculation unit 522b. The PWM signal generation unit 524b generates a PWM signal as a gate signal based on the second command signal and outputs it to the converter 20b. The PWM signal generation unit 524a and the PWM signal generation unit 524b may be synchronized by a carrier synchronization signal.

[0070] As described above, the vehicle system 1 according to the present embodiment is configured to feedback-control the output voltages of the converters 20a and 20b with respect to the same DC voltage command value, thereby making it possible to control the output voltages of the converters 20a and 20b to be the same output voltage.

[0071] Although several 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 modifications are included in the scope and spirit of the invention, and are included in the invention and its equivalents described in the claims. [Explanation of symbols]

[0072] 1: vehicle system, 10: AC power supply, 20a, 20b: converter, 30a to 35a, 30b to 35b: inverter, 40 to 45: motor, 50: control unit, 52a: first control unit, 52b: second control unit.

Claims

1. A plurality of AC motors; a plurality of first AC converters corresponding to the plurality of AC motors, each of which converts DC power supplied from a first DC power source into AC power and supplies the AC power to each of the plurality of AC motors; a plurality of second DC-AC converters corresponding to the plurality of AC motors, each converting DC power supplied from a second DC power source different from the first DC power source into AC power and supplying the AC power to each of the plurality of AC motors; A vehicle system comprising:

2. the AC motor is a double-winding motor having a first winding and a second winding, supplying AC power from the first AC converter to the first winding; The vehicle system according to claim 1 , wherein the second winding is supplied with AC power from the second DC-AC converter.

3. The first DC power source and the second DC power source are provided, 3. The vehicle system according to claim 2, wherein the voltages of the first DC power supply and the second DC power supply are controlled to be the same voltage and supplied to each of the first DC converters and the second DC converters.

4. a first control unit that controls the first DC power supply to a predetermined voltage in accordance with a first voltage command value; a second control unit that controls the second DC power supply to the predetermined voltage in accordance with a second voltage command value that commands a voltage equal to the first voltage command value; The vehicle system of claim 3 .

5. the first control unit controls the first DC power supply to the predetermined voltage based on an output voltage of the first DC power supply and a voltage value of the first voltage command value; 5 . The vehicle system according to claim 4 , wherein the second control unit controls the second DC power supply to the predetermined voltage based on an output voltage of the second DC power supply and a voltage value of the second voltage command value.

6. The vehicle system according to claim 5 , wherein the first DC power supply and the first control unit are electrically insulated from the second DC power supply and the second control unit.

7. The vehicle system according to claim 6 , wherein the first orthogonal converters and the second orthogonal converters are electrically insulated from each other.

8. 8. The vehicle system according to claim 1, wherein, when any of the plurality of first orthogonal transformers and the plurality of second orthogonal transformers is malfunctioning, outputs of the plurality of first orthogonal transformers and the plurality of second orthogonal transformers are changed depending on the number of malfunctioning orthogonal transformers.

9. 9. The vehicle system according to claim 8, wherein outputs of the first DC converters and the second DC converters are changed so that output states of the first DC power source and the second DC power source are equivalent.

10. The vehicle system according to claim 9 , wherein the first orthogonal converters and the second orthogonal converters are inverters of a two-level circuit type or a three-level circuit type.

11. Further comprising an AC power source; 8. The vehicle system according to claim 1, wherein the first DC power supply and the second DC power supply are converters using a two-level circuit or a three-level circuit that converts AC power output from the AC power supply into DC power.

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