JP6478859B2 - Power conversion device and vehicle - Google Patents

Description

  The present invention relates to a power conversion device and a vehicle that convert DC power into AC power.

  Conventionally, in order to drive a refrigerator, an elevator, and the like, a driving device that outputs a three-phase AC voltage using electric power supplied from a commercial power source is known. Such a drive unit can be used to install a refrigerator, elevator, etc. when power is not supplied due to a failure in a power supply facility such as a power plant, substation, or transmission line due to the effects of a natural disaster such as an earthquake or tsunami. It cannot be driven.

  Therefore, in recent years, a power supply device that supplies power to a drive device when power from a commercial power source cannot be supplied to the drive device is becoming widespread. In such a power supply apparatus, the power conversion apparatus 7 as shown in FIG. 10 is mounted, and an inverter 71 provided in the power conversion apparatus 7 generates a DC voltage output from the battery 8 mounted in the power supply apparatus. It is converted to a three-phase rectangular wave voltage. Further, the low-pass filter 72 removes harmonics from the rectangular wave voltage converted by the inverter 71 and outputs a three-phase AC voltage whose waveform is close to a sine wave.

  In addition to the three-phase AC voltage for operating the refrigerator, elevator, etc., when the power supply facility is no longer supplied due to the failure of the power supply facility, the single-phase AC voltage for operating the lighting fixture, IH cooker, etc. Demand arises. For example, if an IH cooker can be used in a disaster-stricken area, the disaster-stricken person can have a freshly prepared meal, which not only helps maintain and promote health, but also helps cooks staying in the disaster-stricken area. It also helps to improve work motivation and maintain mental health.

  Therefore, by supplying a known Scott transformer 73 to the output side of the electric circuit shown in FIG. 10, a power supply apparatus equipped with a power conversion system that converts a three-phase AC voltage into two sets of single-phase AC voltages is supplied. Can be considered. FIG. 11 is a diagram illustrating an example of a known power conversion system that converts a three-phase AC voltage into a single-phase AC voltage. As shown in FIG. 11, a Scott transformer 73 is connected to the low-pass filter 72 shown in FIG. 10, and the Scott transformer 73 converts the three-phase AC voltage into two sets of single-phase AC voltages.

  In the Scott transformer 73 shown in FIG. 11, a primary transformer 731 is provided between VWs on the output side of the low-pass filter, and a secondary transformer 732 having a number of turns equal to the number of turns of the primary transformer 731 is provided. Further, a primary transformer 733 is provided between the U point and the T point which is intermediate between VW, and a secondary transformer 734 having a winding number √3 / 2 times the winding number of the primary transformer 733 is further provided. As a result, the three-phase AC voltage whose phase is shifted by 120 ° as shown in FIG. 12A is converted into two sets of single-phase AC voltages whose phase is shifted by 90 ° as shown in FIG. .

  Also, as described in Patent Document 1, a bidirectional switch is provided for each phase of a three-phase AC power supply, and a switching pattern that defines the timing and time for opening and closing the switch based on a single-phase output voltage command is created. A control device that converts a three-phase AC voltage into a single-phase AC voltage by controlling a switch based on the created switching pattern is known.

  Further, as described in Patent Document 2, a conversion circuit that converts a three-phase AC voltage into a single-phase AC voltage using a transformer connected between two terminals of the three-phase AC voltage is known.

JP 2000-299984 A JP 2005-080484 A

  However, when a method of outputting two sets of single-phase AC voltages by connecting known Scott transformers when a natural disaster occurs, the Scott transformers must be stocked from normal times. The Scott transformer has a mass of several tens to several hundreds kilos, and its outer dimensions are large. Therefore, it is difficult to secure a storage space. In addition, the Scott transformer is expensive, and it is not realistic to store tens of thousands of units that are necessary when a large-scale natural disaster occurs.

  Moreover, since the control apparatus described in Patent Document 1 requires a process of creating a switching pattern based on a single-phase output voltage command, a three-phase AC power line voltage, and an input current distribution ratio in order to control the switch, There may be a problem that the load on the control device increases. In addition, there may be a problem that the cost increases by providing as many as six bidirectional switches.

  Moreover, since the control apparatus described in patent document 2 converts a three-phase alternating current voltage into a single-phase alternating current voltage using a transformer, it must be equipped with a converter in a control apparatus, and the control apparatus is enlarged. There may be a problem that cannot be avoided.

  Therefore, the objective of this invention made | formed in view of this point is to prevent the enlargement of a power converter device and to convert direct-current power into alternating current power at low cost.

  In order to solve the above-described problem, a power conversion device according to the present invention includes an inverter that outputs a three-phase AC voltage, and a low-pass filter connected to the inverter, and the low-pass filter is connected to the inverter. Three input terminals electrically connected to each output terminal, three inductors connected between the three input terminals and the corresponding three output terminals, and a first of the three inductors And a capacitor connected between the output sides of the second inductor, a capacitor connected between the output sides of the second and third inductors, and a capacitor connected between the output sides of the third and first inductors. And a switching element that stops the output from one of the three output terminals, and the output terminal of the low-pass filter has three When receiving a signal representing connecting a load operating with an AC voltage, the switching element is closed, and when receiving a signal indicating connecting a load operating with a single-phase AC voltage to the output terminal of the low-pass filter, The switching element is opened.

  Further, in the power conversion device according to the present invention, the switching element is between the first capacitor and a connection point of the first and second capacitors connected to the one output terminal among the capacitors. , And connected between the connection point and the second capacitor.

  In the power conversion device according to the present invention, the switching element is connected between a connection point of the first and second capacitors connected to the one output terminal and the one output terminal. It is characterized by.

  In addition, the power converter according to the present invention receives the voltage command value representing the AC voltage to be output from the power converter and performs PWM control on the inverter so as to output the AC voltage represented by the voltage command value. It is characterized by having a control part to perform.

  Moreover, the power converter device which concerns on this invention WHEREIN: The said control part receives the said voltage command value from the load connected to the output terminal of the said power converter device via a communication network, It is characterized by the above-mentioned.

  In addition, a vehicle according to the present invention includes the above power conversion device.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to prevent the enlargement of a power converter device and to convert a three-phase alternating voltage into a single-phase alternating voltage at low cost.

It is a figure which shows the electrical constitution of the power conversion system using the battery mounted in the vehicle which concerns on embodiment of this invention. It is a figure which shows the electrical structure of the power converter device shown in FIG. It is a figure which shows the rectangular wave switching signal produced | generated based on a voltage command value and a triangular wave. It is a figure which shows the time change of the three-phase alternating voltage between each phase and each line in effective voltage 200V. It is a figure which shows the time change for 1 period of the switching signal and output voltage by PWM control. It is a figure which shows the time change for the 1/4 cycle of the switching signal and output voltage in effective voltage 200V and 100V by PWM control. It is a figure which shows the time change of the single phase alternating voltage of effective voltage 200V. It is a figure which shows the time change of the single phase alternating voltage of effective voltage 100V. It is a figure which shows the other example of the electric constitution of the power converter device shown in FIG. It is a figure which shows the electrical constitution of the conventional power converter device. It is a figure which shows the electrical constitution of the conventional power converter device which connected the Scott transformer. It is a figure which shows the time change of a three-phase alternating voltage, and the time change of two sets of single phase alternating voltages.

  A power conversion system 100 according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the power conversion system 100 includes a power conversion device 1, a vehicle control device 2, and a load that is a three-phase load 31 or a single-phase load 32 connected to the power conversion device 1. The power conversion device 1 is provided in a vehicle 6 such as a hybrid truck, and is electrically connected to a vehicle control device 2 for driving the vehicle 6.

  The vehicle control device 2 includes a DC power supply 21, and the DC power supply 21 is connected to an inverter 22. Further, the inverter 22 converts a DC voltage supplied from the DC power source 21 into an AC voltage and supplies the AC voltage to the motor 23. The vehicle control device 2 includes an automatic clutch 24 and an engine 25 connected to a motor 23. The automatic clutch 24 and the engine 25 are controlled by a transmission ECU (Electronic Control Unit) 26 and an engine ECU 27, respectively. The motor 23 is supplied with electric power from the DC power source 21 or supplied with power from the engine 25 to drive the wheels.

  Further, the DC power source 21 outputs a DC voltage to the power conversion device 1.

  The power conversion device 1 converts a DC voltage input from the DC power source 21 into a three-phase AC voltage, and outputs the three-phase AC voltage to a three-phase load 31 such as a refrigerator or an elevator that operates with the three-phase AC voltage. Alternatively, the power conversion device 1 converts the DC voltage input from the DC power source 21 into a single-phase AC voltage, and outputs the single-phase AC voltage to a single-phase load 32 such as a lighting fixture or an IH cooker that operates with the single-phase AC voltage. .

  FIG. 2 is a diagram illustrating a configuration of the power conversion device 1 of the present embodiment. As shown in FIG. 2, the power conversion device 1 includes an inverter 4 and a low-pass filter 5.

  In the inverter 4, a capacitor 41 is connected to the DC power supply 21 in parallel. A braking unit in which the braking resistor 42 and the switching element 43 are connected in series is connected in parallel to the capacitor 41. Further, switching elements 44 ua and 44 ub are connected in series as the U phase of the inverter 4, and freewheeling diodes 45 ua and 45 ub are connected in parallel to the switching elements 44 ua and 44 ub, respectively. The U phase of the inverter 4 is connected to the capacitor 41 in parallel.

  Similarly, as the V phase of the inverter 4, two switching elements 44va and 44vb connected in series are connected in parallel to the capacitor 41, and the freewheeling diodes 45va and 45vb are connected in parallel to the switching elements 44va and 44vb, respectively. The Similarly, as the W phase of the inverter 4, two switching elements 44wa and 44wb connected in series are connected in parallel to the capacitor 41, and the freewheeling diodes 45wa and 45wb are connected in parallel to the switching elements 44wa and 44wb, respectively. The These switching elements are realized by self-extinguishing semiconductor elements such as IGBTs (insulated gate bipolar transistors).

  The inverter 4 includes a control unit 46 that controls each circuit element. The U-phase, V-phase, and W-phase switching elements are opened and closed based on switching signals Su, Sv, and Sw generated by pulse width modulation (PWM) control of the control unit 46, respectively. Is converted into a three-phase AC voltage. The control unit 46 is realized by a microcomputer.

  Next, with reference to FIGS. 3 to 6, the pulse width modulation control related to the U phase by the control unit 46 when the DC voltage is converted into a 200 V three-phase AC voltage will be described.

The control unit 46 receives a voltage command value based on a load phase signal indicating whether the load is the three-phase load 31 or the single-phase load 32 and the effective voltage of the single-phase load 32, which are input by the user. And the control part 46 produces | generates the sine wave SIN as shown to 1 ^* sin of FIG. 3 based on a voltage command value. Further, the control unit 46 generates a triangular wave.

  Then, the control unit 46 compares the sine wave SIN and the triangular wave, and generates a signal of the switching signal Su = 1 during the period of the sine wave SIN ≧ triangular wave. In addition, during the period in which the sine wave SIN <triangular wave, a signal with the switching signal Su = 0 is generated. As a result, a switching signal Su indicated by PWM 200 in FIG. 3 is generated. Further, based on the generated switching signal Su, the control unit 46 closes the switching elements 44ua and 44ub when the switching signal Su = 1, and opens the switching elements 44ua and 44ub when the switching signal Su = 0.

In FIG. 3, the voltage command value for ¼ period and the switching signal Su generated based on the voltage command value are shown as examples, but the voltage command value as indicated by 1 ^* sin in FIG. 5 continues. By performing the same processing based on, the switching signal Su for one cycle is generated.

  The control unit 46 performs the above-described pulse width modulation control described for the U phase with respect to the V phase and the W phase by shifting the phases by 120 ° to generate the switching signals Sv and Sw. As a result, the DC voltage input to the inverter 4 is converted into a three-phase AC voltage as shown by the U-phase voltage, the V-phase voltage, and the W-phase voltage in FIG.

  The above voltage command value is the difference in voltage between the U phase, V phase, and W phase as shown in FIG. 4, and the effective voltage for each of the UV lines, VW lines, and WU lines is 200 V, that is, It is input so that the maximum voltage is about 282V.

In the above, the example in which the power converter device 1 converts a DC voltage into a 200V three-phase AC voltage has been described. When the power conversion device 1 converts the DC voltage into a three-phase AC voltage of 100 V, the control unit 46 determines the amplitude of the sine wave SIN (see 0.5 ^* sin in FIG. 6) determined based on the voltage command value. What is necessary is just to make it 0.5 times the sine wave SIN (refer 1 ^* sin of FIG. 6) in the case of converting into the 200V three-phase alternating voltage. When the sine wave SIN indicated by 0.5 ^* sin is generated, the time when Su = 1 in the switching signal Su is the time when Su = 1 when the sine wave SIN indicated by 1 ^* sin is generated. Almost half of In this way, the sine wave SIN is generated based on the voltage command value, and the switching signal Su is generated in the same manner as described above. Then, the amplitude of the AC voltage V _u is controlled by controlling the switching elements 44 ua and 44 ub based on the generated switching signal Su.

In FIG. 6, the voltage command value for ¼ period and the switching signal Su generated based on the voltage command value are shown as examples, but the voltage as indicated by 0.5 ^* sin in FIG. 5 continues. By performing the same processing based on the command value, the switching signal Su for one cycle is generated.

Referring to FIG. 2 again, in the low-pass filter 5, inductors 51u, 51v, and 51w are connected in series to input terminals respectively connected to the output terminals 47u, 47v, and 47w of the inverter 4. A capacitor 52uv is connected between the output sides of the inductors 51u and 51v. Similarly, a capacitor 52vw is connected between the output sides of the inductors 51v and 51w, and a capacitor 52wu is connected between the output sides of the inductors 51w and 51u. These inductors 51u, 51v, and 51w, and capacitors 52uv, 52vw, and 52wu remove the harmonics of the AC voltages V _u , V _v , and V _w output from the inverter 4 and make the waveform closer to a sine wave. Configure the output filter.

  Furthermore, a phase conversion switching element 53uv is connected between the capacitor 52uv and the connection point of the capacitors 52uv and 52wu. A phase conversion switching element 53uw is connected between the capacitor 52wu and the connection point of the capacitors 52uv and 52wu. When the load phase signal received by the control unit 46 indicates that the load is the three-phase load 31, the control unit 46 closes the phase conversion switching elements 53uv and 53uw. When the load phase signal indicates that the load is the single-phase load 32, the control unit 46 opens the phase conversion switching elements 53uv and 53uw.

  The three output terminals 54u, 54v, and 54w of the low-pass filter 5 are connected to a three-phase load 31 that operates with a three-phase AC voltage. Of the three output terminals 54u, 54v and 54w of the low-pass filter 5, two output terminals 54v and 54w are connected to a single-phase load 32 that operates with a single-phase AC voltage.

By providing the above configuration, when the load phase signal indicating that the load is the three-phase load 31 is input to the power conversion device 1 in the present embodiment by the user, the control unit 46 controls the U phase and the V phase. , And W phase are subjected to pulse width modulation control so as to output AC voltages V _u , V _v , and V _w that are shifted from each other by 120 °. At this time, the phase conversion switching elements 53uv and 53uw are closed, and the AC voltages V _u , V _v , and V _w output from the inverter 4 are input to the low-pass filter 5. Then, the harmonics of the AC voltages V _u , V _v , and V _w of each phase input to the low-pass filter 5 are removed, and a waveform close to a sine wave is generated. The alternating voltages V _u , V _v , and V _w having a waveform close to a sine wave are output to the output terminals 54 u, 54 _v , and 54 _w and input to the three-phase load 31, respectively.

When the load phase signal indicating that the load is the single-phase load 32 is input by the user and the voltage command value indicating that the effective voltage of the single-phase load 32 is 200 V is input, the control unit 46 The pulse width modulation control for the U phase is stopped, and the AC voltages V _v and V _w that become the VW line voltage of the effective voltage 200 V, which are shifted from each other by 120 ° for the V phase and the W phase as shown in FIG. Pulse width modulation control is performed so as to output. At this time, the control unit 46 opens the phase conversion switching elements 53uv and 53uw, thereby forming an output filter including the inductors 51v and 51w and the capacitor 52vw. Then, the output filter, a low pass harmonic of the AC voltage input to the V-phase and W-phase of the filter 5 V _v and V _w is removed, the waveform close to a sine wave is generated. Further, AC voltages V _v and V _w having a waveform close to a sine wave are output to the output terminals 54 _v and 54 _w , respectively, and one set of single-phase AC power is input to the single-phase load 32.

Similarly, when a load phase signal indicating that the load is a single-phase load 32 is input by the user and a voltage command value indicating that the effective voltage of the single-phase load 32 is 100 V is input, the control unit 46 Stops the pulse width modulation control for the U phase, and the AC voltages V _v and V _w that become the VW line voltage of the effective voltage 100 V, shifted by 120 ° from each other for the V phase and the W phase as shown in FIG. The pulse width modulation control is performed so as to output. At this time, when the control unit 46 opens the phase conversion switching elements 53uv and 53uw, an output filter including the inductors 51v and 51w and the capacitor 52vw is configured. Then, the output filter, a low pass harmonic of the AC voltage input to the V-phase and W-phase of the filter 5 V _v and V _w is removed, the waveform close to a sine wave is generated. Further, AC voltages V _v and V _w having a waveform close to a sine wave are output to the output terminals 54 _v and 54 _w , respectively, and one set of single-phase AC power is input to the single-phase load 32.

  Thus, the power converter 1 of this embodiment can supply three-phase alternating current power to the three-phase load 31 by the control part 46 closing the phase conversion switching elements 53uv and 53uw, and can perform the phase conversion switching. Single-phase AC power can be supplied to the single-phase load 32 by opening the elements 53uv and 53uw. That is, a three-phase AC voltage or a single-phase AC voltage can be output according to the load without using an expensive large-sized device such as a Scott transformer.

  Moreover, in this embodiment, since the control part 46 performs the pulse width modulation control about each phase of the inverter 4 based on a voltage command value, electric power can be supplied to various loads from which an effective voltage differs. Therefore, when a disaster occurs, a lighting device, an IH cooker, or the like, which is a single-phase load 32, is operated in addition to a refrigerator, an elevator, or the like, which is a three-phase load 31, without using a large device. It becomes possible. Furthermore, it becomes possible to operate various devices required in a disaster area such as a mobile phone charger, a television broadcasting device, a washing machine, a seawater desalination device, a building pump power supply device, and a fast food cooking device.

  Moreover, in this embodiment, the power converter device 1 outputs a set of single-phase AC power to the single-phase load 32 using the V-phase and W-phase of the inverter 4. Since only one set of single-phase AC power is output, there is no need to consider the balance when two sets of AC power are output. Therefore, it is possible to output single-phase AC power at a low cost without providing a Scott transformer for outputting two sets of AC power in parallel.

  Moreover, in this embodiment, since alternating current power is output using the direct current power supply 21 with which vehicles 6, such as a hybrid truck, are provided, the electric energy of the alternating current power is less than 10 kW. Therefore, it is possible to output AC power without being restricted by the Electricity Business Law, in which the chief electric engineer must be notified. For example, after a natural disaster occurs, it is assumed that there will be a shortage of personnel related to recovery, support, etc., so even if there is no electrical chief engineer, AC power can be output and various devices necessary for life can be operated The device is very useful especially in disaster area support.

  In this embodiment, the control unit 46 receives the load phase signal and the voltage command value from the load connected to the output terminal of the low-pass filter 5 via the communication network. A voltage command value may be received. In this case, the control unit 46 stops or starts the U-phase operation based on the received load phase signal, and generates the switching signals Su, Sv, and Sw based on the voltage command value. The controller 46 opens and closes the phase conversion switching elements 53uv and 53uw based on the received load phase signal.

In the present embodiment, when the load is the single-phase load 32, the phase conversion switching elements 53uv and 53uw are opened and the V-phase and W-phase AC voltages of the low-pass filter 5 are output. The switching elements 53vw and 53uv may be opened and the W-phase and U-phase AC voltages V _w and V _{u of} the low-pass filter 5 may be output. Similarly, when the load is a single-phase load 32, the phase conversion switching elements 53uw and 53vw are opened, and the U-phase and V-phase AC voltages V _u and V _{v of} the low-pass filter 5 are output. Good.

In the present embodiment, the phase conversion switching element 53uv is connected between the capacitor 52uv and the connection point between the capacitors 52uv and 52wu, and the phase conversion switching element 53uv is connected to the connection point between the capacitor 52wu and the capacitors 52uv and 52wu. Connected between. However, as shown in FIG. 9, the phase conversion switching element 53uv is connected between the output-side terminal of the inductor 51u and the connection point of the capacitors 52uv and 52wu, and the phase conversion switching element 53uv is connected to the capacitors 52uv and 52wu. May be connected to the output terminal 54u. In this case, when the control unit 46 opens the phase conversion switching elements 53uv and 53uw, an output filter including the inductors 51v and 51w and the capacitors 52uv, 52wu, and 52vw is configured. The harmonics of the AC voltage V _v and V _w is input to the V-phase and W-phase are removed, are generated near-sinusoidal waveforms, a set of single-phase AC power is input to the single-phase load 32 The In this case, the phase conversion switching element 53uv can be omitted.

  Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Vehicle control apparatus 4 Inverter 5 Low-pass filter 6 Vehicle 21 DC power supply 22 Inverter 23 Motor 24 Automatic clutch 25 Engine 26 Transmission ECU
27 Engine ECU
31 Three-phase load 32 Single-phase load 41 Capacitor 42 Braking resistors 43 and 44 Switching element 45 Free-wheeling diode 46 Control part 47 Output terminal 51 Inductor 52 Capacitor 53 Phase conversion switching element 54 Output terminal 100 Power conversion system Su, Sv, Sw Switching signal

Claims (6)

An inverter that outputs a three-phase AC voltage;
A low-pass filter connected to the inverter,
The low pass filter is:
Three input terminals electrically connected to the respective output terminals of the inverter;
Three inductors connected between the three input terminals and the corresponding three output terminals;
Of the three inductors, a capacitor connected between the output sides of the first and second inductors, a capacitor connected between the output sides of the second and third inductors, and the third and first inductors A capacitor connected between the output sides of the
A switching element that stops output from one of the three output terminals, and accepts a signal indicating that a load that operates with a three-phase AC voltage is connected to the output terminal of the low-pass filter And the switching element is closed, and the switching element is opened when receiving a signal indicating that a load operating with a single-phase AC voltage is connected to the output terminal of the low-pass filter.   The switching element includes, among the capacitors, a connection point between the first and second capacitors connected to the one output terminal and the first capacitor, and the connection point and the second capacitor. The power converter according to claim 1, wherein the power converter is connected between the two.   2. The electric power according to claim 1, wherein the switching element is connected between a connection point of first and second capacitors connected to the one output terminal and the one output terminal. Conversion device.   A control unit that receives a voltage command value representing an AC voltage to be output from the power converter and performs PWM control on the inverter so as to output an AC voltage represented by the voltage command value. Item 4. The power conversion device according to any one of Items 1 to 3.   The power converter according to claim 4, wherein the control unit receives the voltage command value from a load connected to an output terminal of the power converter via a communication network.   A vehicle comprising the power conversion device according to any one of claims 1 to 5.

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