Power conversion device adjustment system and power conversion device adjustment method

Abstract

The present invention adjusts variation in the operation of a power conversion device in which a power semiconductor is used. The present invention pertains to an adjustment device for a power conversion device that performs power conversion using a power semiconductor, said adjustment device for a power conversion device comprising: a delay time measurement unit for measuring a reference increase delay time that is the delay time of an output voltage increase output when a switching signal instructing an increase in output voltage is input to a reference power conversion device serving as a reference for adjustment; an adjustment value generation unit that determines a voltage increase adjustment value from the difference between the reference increase delay time and the delay time of the output voltage increase output when the switching signal is input to the power conversion device; and an adjustment value writing unit that writes the voltage increase adjustment value determined by the adjustment value generation unit to an adjustment unit of the power conversion device.

Description

Power converter adjustment system and power converter adjustment method

[0001] The present invention relates to a power converter adjustment system and a power converter adjustment method.

[0002] The spread of environmental protection has increased the demand for electric motors, and so has the demand for power conversion devices to drive them. The development of power semiconductor elements is important for power conversion devices, but developing power semiconductor elements that match the specifications of each electric motor every time results in low yields and increased development costs. For this reason, once a power conversion device is developed, it is important to use it to drive electric motors of the same capacity range as much as possible, and to be able to support large-capacity electric motors by connecting power semiconductor elements in parallel.

[0003] Patent Document 1 discloses a power semiconductor element drive circuit that can improve not only current imbalance during switching operation but also current imbalance during steady-state operation. The power semiconductor element drive circuit is provided corresponding to each of a plurality of power semiconductor elements connected in parallel and drives the power semiconductor elements. The power semiconductor element drive circuit includes a memory unit that stores characteristic information of the power semiconductor elements and a gate drive control unit that controls gate drive conditions of the power semiconductor elements based on the characteristic information stored in the memory unit.

[0004] JP 2017-46438 A

[0005] The power semiconductor element drive circuit of Patent Document 1 discloses that it adjusts the imbalance in the output current of each of a plurality of power semiconductors connected in parallel.

[0006] However, the drive circuit of Patent Document 1 adjusts a power conversion device using power semiconductors by referring to characteristic information of the power semiconductors, but does not consider what adjustment values ​​are set using the characteristic information to adjust the operation of each power semiconductor to a target operation. An object of the present invention is to create a power conversion device with stable performance using power semiconductors with variations in characteristics.

[0007] The object of the present invention is achieved by an adjustment device for a power conversion device that performs power conversion using power semiconductors, the adjustment device for a power conversion device comprising: a delay time measurement unit that measures a reference rise delay time, which is the delay time of the output voltage rise that is output when a switching signal instructing an output voltage increase is input to a reference power conversion device that serves as the basis for adjustment; an adjustment value generation unit that determines a voltage rise adjustment value from the difference between the delay time of the output voltage rise that is output when a switching signal is input to the power conversion device and the reference rise delay time; and an adjustment value writing unit that writes the voltage rise adjustment value determined by the adjustment value generation unit to the adjustment unit of the power conversion device.

[0008] According to the present invention, it is possible to adjust the variations in the operation of a power conversion device using a power semiconductor. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0009] Increase in capacity by adding inductance Increase in capacity by new development Diagram explaining output voltage before adjustment Diagram explaining output voltage after adjustment Diagram explaining output voltage before adjustment Diagram explaining output voltage after adjustment System configuration diagram of a two-stage system in an embodiment of the present invention System configuration diagram of a one-stage system in an embodiment of the present invention Example of a configuration diagram of an adjustment device in an embodiment of the present invention Example of a circuit diagram of a power conversion device in an embodiment of the present invention Diagram explaining an overview of adjustment processing in an embodiment of the present invention Example of a flowchart showing processing of an adjustment device (single unit) in an embodiment of the present invention Example of a flowchart showing processing of adjustment devices (parallel) in an embodiment of the present invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing for explaining the embodiments, the same components are given the same names and reference numerals as much as possible, and repeated explanations thereof will be omitted.

[0011] The present invention is not limited to the following examples, and includes various modifications and equivalent configurations within the spirit and scope of the appended claims. For example, the above examples have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations.

[0012] Furthermore, the processing units described in the embodiments may be realized in hardware, for example by designing some or all of them as integrated circuits, or may be realized in software by having a processor interpret and execute a program that realizes each function.

[0013] The tables, areas, etc. described in the embodiments may be a database (DB) or data stored in the main memory.

[0014] Power conversion devices are often made using power semiconductors. However, the characteristics of each power semiconductor vary. Therefore, if only power semiconductors with similar characteristics are used to drive external devices such as motors, the yield of the power semiconductors will decrease, leading to increased costs.

[0015] Furthermore, in recent years, there has been a demand for large-capacity power conversion devices to control motors in electric vehicles and the like. However, each time such devices are required, it is necessary to develop a power semiconductor with the required capacity and a drive unit to drive it, as shown in Figure 1B, which also increases costs.

[0016] To solve this problem, it has been considered to combine multiple existing power semiconductors to create a large-capacity power conversion device, as shown in Figure 1A. However, there is a problem that the variations in power semiconductors cause rapid degradation of specific power semiconductors.

[0017] One way to solve this problem is to add a coil 5 to adjust the characteristics of each power semiconductor 4, thereby absorbing the differences in the characteristics of the power semiconductors, as shown in Figure 1A. In this case, it is possible to reduce costs by standardizing the drive unit, as shown in the lower diagram of Figure 1A, but the costs involved in measuring the characteristics of the power semiconductors 4 and selecting and adjusting the coil 5 are unavoidable.

[0018] Next, the variations in the characteristics of power semiconductors will be explained.

[0019] 2 is a diagram illustrating the output voltage of the power semiconductors before regulation. The gate voltage of the power semiconductors rises in response to the rising edge of the output switching signal 31 output from the control unit. The output voltage signal 32 of the first power semiconductor rises significantly later than the output voltage signal 33 of the second power semiconductor.

[0020] Furthermore, the gate voltage of the power semiconductor drops in response to the falling edge of the output switching signal 31. In this case as well, the output voltage signal 32 of the first power semiconductor falls significantly later than the output voltage signal 33 of the second power semiconductor.

[0021] When there is such a variation in the power semiconductors, the load on the second power semiconductor is large, causing the second power semiconductor to deteriorate rapidly. To solve this problem, it is necessary to delay the rise and fall of the gate voltage of the second power semiconductor and adjust it to synchronize with the first power semiconductor.

[0022] 3 shows the output voltage of the power semiconductor after regulation. When the output switching signal 31 is input, the output switching signal 34 that the regulator 1 supplies to the power converter 1 is an output switching signal 34 that is substantially unregulated from the output switching signal 31. This may be exactly the same as the output switching signal 31, but there may be some delay due to the nature of the electronic circuit.

[0023] On the other hand, the output switching signal 35 supplied to the power conversion device 2 by the adjustment unit 2 is adjusted to be a delayed output switching signal 35. This adjustment delays the rise of the output voltage signal 33 of the power conversion device 2, so that it rises at approximately the same time as the output voltage signal 32 of the power conversion device 1, near the optimum value 36.

[0024] Similarly, by adjusting the rise time of the output voltage signal supplied to the power conversion device by each adjustment unit, the output voltage signal falls at approximately the same time as the output voltage signal 32 of power conversion device 1, near the optimum value 37. Figure 4 is a diagram explaining the output voltage before adjustment. The signal of power conversion device A rises before the signal of power conversion device B, following the rise of switching signal 50. The graphs of currents IceA and IceB shown below do not match, with current IceA of power conversion device A rising first and being higher than the peak of current IceB of power conversion device B, resulting in an imbalance.

[0025] Regarding the falling edge of the switching signal 50, the signal of power conversion device A falls before the signal of power conversion device B. The graphs of the currents IceA and IceB shown below also do not match, with the current IceB of power conversion device B being lower than the current IceB of power conversion device A. The voltages also do not match.

[0026] In order to adjust for this variation, the rise and fall of power converter A is delayed as shown in FIG. 5, thereby matching the output current and output voltage of power converter A and power converter B and eliminating the imbalance.

[0027] 6A is an example of a two-stage system configuration diagram in an embodiment of the present invention. An individual power conversion device 23 is assembled and adjusted by an individual adjustment device 20. A reference power conversion device 21, which serves as a reference for the power conversion devices, is connected to the individual adjustment device 20. Using data from the reference power conversion device 21, an individual adjustment unit 22 adjusts the individual power conversion device 23 to produce an adjusted individual power conversion device 25.

[0028] A large-capacity parallel power conversion system 26 is configured by connecting a plurality of individually regulated power conversion systems 25 in parallel. The parallel power conversion systems 26 are regulated by a parallel regulating system 24. The parallel regulating system 24 is equipped with a parallel regulating unit 27, which measures the change in output voltage of each of the power conversion systems that make up the parallel power conversion system 26, identifies the power conversion system that needs regulation, and then determines an regulation value by comparing it with the value of the reference power conversion system 21, and sets the determined regulation value in the determined power conversion system.

[0029] 6B is a diagram showing an example of a one-stage system configuration according to an embodiment of the present invention. In this case, adjustment of each power conversion device is not performed, but rather, parallel power conversion devices 26, which are configured in parallel from the beginning, are set in parallel adjustment device 30 and adjustment is performed.

[0030] The parallel adjustment device 30 is equipped with a reference power conversion device 21, and the parallel adjustment unit 27 directly measures data from the reference power conversion device 21 and uses the data for adjustment. The adjustment method is the same as that of the two-stage parallel adjustment device 24, but because adjustment of individual power conversion devices is not performed, it may not be possible to adjust each of the power conversion devices that make up the parallel power conversion device 26. Furthermore, since the number of power conversion devices that must actually be adjusted increases, it may take more time as the degree of parallelization increases.

[0031] 7 is a diagram illustrating an example of the configuration of an adjustment device according to an embodiment of the present invention. The adjustment start instruction and data such as the tolerance for error are received from the connected host computer via a host IF (Interface). The memory of the CPU (Central Processing Unit) contains a processing reception unit 79 that receives the adjustment start instruction, and a control unit 80 controls the overall adjustment process. A pulse generation unit 75 generates pulses and transmits them to a reference power conversion device 87 and a power conversion device 86 via an input / output unit 83, and an output detection unit 76 detects the voltage output of the reference power conversion device 87 and the power conversion device 86.

[0032] A measuring unit 81 measures the delay of the voltage output, and an adjustment value generating unit 82 calculates an adjustment value based on the measured delay of the voltage output. A writing unit 77 writes the calculated adjustment value to the adjustment unit of the power conversion device, thereby performing adjustment.

[0033] The external memory 73 includes a log data storage unit 84 that stores log data such as the serial number of the power conversion device on which adjustment was performed and the adjustment results, and a setting value table that stores measurement values ​​such as output voltage delay information obtained from the reference power conversion device 87, the allowable error range, etc.

[0034] By storing this information in the set value table 85, when adjustment is performed using the same reference power converter, it is not necessary to measure the reference power converter each time adjustment is performed.

[0035] 8 is an example of a circuit diagram of a power conversion device according to an embodiment of the present invention. In this example, two power conversion devices are connected in parallel to drive a three-phase load 6. A positive DC power supply 91 and a negative DC power supply 92 are provided, and are connected to an FG (Frame Ground) 90. When a switching signal is sent from a control unit 2 to each adjustment unit 93, the adjustment unit 93 adjusts the delay time, and the drive unit 3 drives the power semiconductor elements 4.

[0036] The voltage output of each power semiconductor element 4 is detected by a voltage detection unit 95 and fed back to the control unit 2. Fig. 9 is a diagram illustrating an outline of the adjustment process in this embodiment of the present invention. The control unit outputs a switching signal 201, an adjustment unit 202 delays the switching signal, a drive unit 203 drives a power semiconductor element 204 based on the adjusted switching signal, voltage detection 205 is performed, and the control unit makes a judgment 206.

[0037] Up to this point, the voltage conversion device is operated independently, but when adjusting within the factory, an adjustment value is calculated based on the result of the control unit determination 206 207 , and the calculated adjustment value is written to the adjustment unit 208 .

[0038] 10 is an example of a flowchart showing the processing of an adjustment device (single unit) in an embodiment of the present invention. The reference power conversion device and the adjustment device are connected, and data such as the voltage output delay time when the reference power conversion device is ON and OFF is measured (S101). A pulse output, which is an output switching signal, is sent to the power conversion device to be adjusted (S102). It is determined whether the ON delay time is the same as that of the reference device (S103), and if not, an adjustment value is written to the adjustment unit (S104). A pulse is output again (S105), and it is determined whether the ON delay time is the same as that of the reference device (S106).

[0039] This process is repeated until the ON delay time becomes the same as that of the reference device. If a power electronics device whose delay time is not considered to be the same as that of the reference device is included, the number of repetitions may be limited and the power electronics device may be excluded from adjustment.

[0040] Next, it is determined whether the delay time when turned off is the same as that of the reference device (S107). If not, the adjustment value is written to the adjustment unit (S108), and it is again determined whether the delay time when turned off is the same as the reference value. This process is repeated until the delay time when turned off is the same as that of the reference device. If this adjustment includes a power electronics device whose delay time is not thought to be the same as that of the reference device, the number of repetitions may be limited and the power electronics device may be excluded from adjustment.

[0041] When the ON and OFF delay times become the same as those of the reference device, pulses are output again (S111), and it is determined whether the ON state time is the same as that of the reference device (S112). If they are the same, the adjustment is complete and the process ends. If they are not the same, the process returns to S102 and a retry is made.

[0042] It is determined whether the number of retries has been exceeded (S113), and if so, the output unit outputs the fact that adjustment is not possible and records it in the log (S114).

[0043] 11 is a flowchart showing an example of the processing of the adjustment device (parallel) in the embodiment of the present invention. The adjustment of a power conversion device in which a plurality of power conversion devices are connected in parallel is performed in the same manner as the adjustment of a single power conversion device.

[0044] In the case of parallel connections, a reference device may be connected in the same way as a single power conversion device, and adjustments may be made using the delay time of the reference device, etc. However, when parallel connections are made, it is more important that there is no variation within the connected power conversion devices, so it is also possible to use a power conversion device that has a slower response to switching signals as the reference device.

[0045] Therefore, when making adjustments in S123 and S127, the adjustment value is written to the power electronics device with the earlier timing, thereby delaying the timing and matching it with the power electronics device with the slower response.

[0046] Even in the case of parallel connection, if a power conversion device is included whose delay time is not thought to be the same as that of the reference device, the number of repetitions may be limited and the power conversion device may be excluded from adjustment.

[0047] As with adjustment of a single unit, a reference power conversion device and an adjustment device can be connected first, and data such as the voltage output delay time when the reference power conversion device is turned on and off can be measured, and this can be used as the reference device. By doing this, it is possible to create a large-capacity power converter with more uniform specifications.

[0048] REFERENCE SIGNS LIST 1 Power conversion device 2 Control unit 3 Drive unit 4 Power semiconductor 5 Coil 6 Three-phase load 20 Individual adjustment device 21 Reference power conversion device 22 Individual adjustment unit 23 Individual power conversion device 24 Parallel adjustment device 25 Individually adjusted power conversion device 26 Parallel power conversion device 27 Parallel adjustment unit 29 Individually unadjusted power conversion device 30 Parallel adjustment device 70 Adjustment device 72 CPU 73 External memory 74 Host IF 75 Pulse generation unit 76 Output detection unit 77 Writing unit 79 Processing reception unit 80 Control unit 81 Measurement unit 82 Adjustment value generation unit 83 Input / output unit 84 Log data storage unit 85 Setting value table 86 Power conversion device 87 Reference power conversion device

Claims

1. An adjustment device for a power conversion device that performs power conversion using power semiconductors, comprising: a delay time measurement unit that measures a reference rise delay time, which is the delay time of the output voltage rise output when a switching signal instructing an output voltage increase is input to a reference power conversion device that serves as the basis for adjustment; an adjustment value generation unit that calculates a voltage rise adjustment value from the difference between the delay time of the output voltage rise output when a switching signal is input to the power conversion device and the reference rise delay time; and an adjustment value writing unit that writes the voltage rise adjustment value calculated by the adjustment value generation unit to the adjustment unit of the power conversion device.

2. The adjustment device for a power conversion device according to claim 1, wherein the delay time measurement unit measures a reference drop delay time, which is the delay time of the output voltage drop output when a switching signal instructing an output voltage drop is input to a reference power conversion device that serves as a reference for adjustment; the adjustment value generation unit calculates a voltage drop adjustment value from the difference between the delay time of the output voltage drop output when a switching signal is input to the power conversion device and the reference drop delay time; and the adjustment value writing unit writes the voltage drop adjustment value generated by the adjustment value generation unit to the adjustment unit of the power conversion device.

3. The power conversion device adjustment device according to claim 1, wherein the adjustment value generation unit determines a voltage increase adjustment value for each of the power conversion devices from the difference between the delay time of the output voltage increase output when a switching signal is input to the plurality of power conversion devices and a reference increase delay time, and the adjustment value writing unit writes the voltage increase adjustment value generated by the adjustment value generation unit to the adjustment unit of each of the power conversion devices.

4. The adjustment device for a power conversion device according to claim 3, wherein the delay time measurement unit measures a reference drop delay time, which is the delay time of the output voltage drop output when a switching signal instructing an output voltage drop is input to a reference power conversion device serving as a reference for adjustment; the adjustment value generation unit determines a voltage drop adjustment value for each of the power conversion devices from the difference between the delay time of the output voltage drop output when a switching signal is input to the plurality of power conversion devices and the reference drop delay time; and the adjustment value writing unit writes the voltage drop adjustment value generated by the adjustment value generation unit to the adjustment unit of each of the power conversion devices.

5. The adjustment device for a power conversion device according to claim 1, wherein the adjustment value generation unit determines the power conversion device for which the voltage increase adjustment value needs to be changed and the voltage increase adjustment value from the difference between the delay time of the output voltage increase of the power conversion device output when a switching signal instructing an output voltage increase is input to a parallel power conversion device in which a plurality of the power conversion devices, each having a voltage increase adjustment value written in the adjustment unit, are connected in parallel, and a reference increase delay time; and the adjustment value writing unit writes the voltage increase adjustment value determined by the adjustment value generation unit to the power conversion device for which the voltage increase adjustment value determined by the adjustment value generation unit needs to be changed.

6. The adjustment device for a power conversion device according to claim 5, wherein the adjustment value generation unit determines the power conversion device for which the voltage drop adjustment value needs to be changed and the voltage drop adjustment value from the difference between the delay time of the output voltage drop of the power conversion device output when a switching signal instructing an output voltage drop is input to a parallel power conversion device in which a plurality of the power conversion devices, each having a voltage rise adjustment value written in its adjustment unit, are connected in parallel, and a reference rise delay time; and the adjustment value writing unit writes the voltage drop adjustment value determined by the adjustment value generation unit to the power conversion device for which the voltage drop adjustment value determined by the adjustment value generation unit needs to be changed.

7. A method for adjusting a power conversion device that performs power conversion using power semiconductors, comprising: a delay time measurement unit measuring a reference rise delay time, which is the delay time of the output voltage rise output when a switching signal instructing an output voltage rise is input to a reference power conversion device that serves as the basis for adjustment; an adjustment value generation unit determining a voltage rise adjustment value from the difference between the delay time of the output voltage rise output when a switching signal is input to the power conversion device and the reference rise delay time; and an adjustment value writing unit writing the voltage rise adjustment value determined by the adjustment value generation unit to an adjustment unit of the power conversion device.

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