Power converter, its control method, and control program

Abstract

To provide a small power conversion device. [Solution] The power conversion device 100 comprises a three-phase single-phase matrix converter 110, an ACDC converter 130, a transformer 120 connected between the three-phase single-phase matrix converter 110 and the ACDC converter 130, and a power pulsation compensation circuit 150 having an inductor L51 and a capacitor Cbuf connected in series. The power pulsation compensation circuit 150 is connected between the center tap of the winding W22 on the ACDC converter 130 side of the transformer 120 and the negative terminal side of the ACDC converter 130.

Description

Technical Field

[0001] The present invention relates to a power conversion device, a control method thereof, and a control program.

Background Art

[0002] Conventionally, a charger having a rectifier, a PFC (Power Factor Correction) circuit, and a DCDC converter has been used as a charger for electric vehicles (for example, Patent Document 1). In such a charger, a DC link capacitor is disposed between the PFC circuit and the DCDC converter in order to smooth the DC power input to the DCDC converter. This DC link capacitor has contributed to the increase in the size of the charger.

[0003] Patent Document 2 discloses a charger having a three-phase single-phase matrix converter, a transformer, and an ACDC converter. In this charger, since it has a three-phase single-phase matrix converter that directly converts three-phase AC power into a single-phase AC power supply, there is no need for a DC link converter, and the charger can be miniaturized.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] There are various types of power supply specifications for the currently installed charging equipment. For example, there are three-phase 22kW / 32A, three-phase 11kW / 16A, single-phase 7.2kW / 32A, and single-phase 3.6kW / 16A. The charger disclosed in Patent Document 2 can use a three-phase AC power supply, but cannot use a single-phase AC power supply.

[0006] The present invention aims to provide a compact power conversion device. [Means for solving the problem]

[0007] To solve the above problems, a power conversion device according to one embodiment of the present invention comprises a three-phase single-phase matrix converter, an AC / DC converter, a transformer connected between the three-phase single-phase matrix converter and the AC / DC converter, and a power pulsation compensation circuit having an inductor and a capacitor connected in series, wherein the power pulsation compensation circuit is connected between the center tap of the winding on the AC / DC converter side of the transformer and the negative terminal side of the AC / DC converter.

[0008] A control method according to one embodiment of the present invention is a control method for controlling a power converter, which is performed by a computer, wherein the power converter comprises a three-phase single-phase matrix converter, an AC / DC converter, a transformer connected between the three-phase single-phase matrix converter and the AC / DC converter, and a power pulsation compensation circuit having an inductor and a capacitor connected in series, wherein the power pulsation compensation circuit is connected between the center tap of the winding on the AC / DC converter side of the transformer and the negative terminal side of the AC / DC converter, and the control method comprises the step of controlling the switches of the three-phase single-phase matrix converter and the switches of the AC / DC converter so as to compensate for the pulsation of the input power input from the single-phase AC power supply using the capacitor of the power pulsation compensation circuit when a single-phase AC power supply is connected to the three-phase single-phase matrix converter.

[0009] A control program according to one embodiment of the present invention causes a computer to execute the above control method. [Effects of the Invention]

[0010] According to the present invention, it becomes possible to provide a compact power conversion device. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows a power converter 100 according to one embodiment of the present invention. [Figure 2] This diagram illustrates a power converter 100 connected to a three-phase AC power supply 200 and a battery 400. [Figure 3] This diagram illustrates a power converter 100 connected to a single-phase AC power supply 300 and a battery 400. [Figure 4] This figure shows an example of switches S11 to S16. [Figure 5] This diagram illustrates the relationship between the instantaneous power value PIN of the single-phase AC power input from the single-phase AC power supply 300 and the instantaneous power value pbuf of the power output from the capacitor Cbuf. [Figure 6] This figure shows an example of the relationship between the output voltage v1 of the three-phase single-phase matrix converter 110 and the input voltage v2 of the AC / DC converter 130. [Figure 7] This diagram illustrates the power flow on the AC / DC converter 130 side during the charging period. [Figure 8] This diagram illustrates the power flow on the AC / DC converter 130 side during the discharge period. [Figure 9] This figure shows an example of the relationship between the output voltage v1 of the three-phase single-phase matrix converter 110 and the input voltage v2 of the AC / DC converter 130. [Figure 10] This figure shows an example of a processing operation performed in the control unit 140. [Figure 11] This figure shows an example of the relationship between the input voltage v2 of the AC / DC converter 130 and the switching control of switches S31 to S34 of the AC / DC converter 130. [Figure 12] This figure shows an example of the relationship between the input voltage v2 of the AC / DC converter 130 and the switching control of switches S31 to S34 of the AC / DC converter 130. [Figure 13] This figure shows another example of the power pulsation compensation circuit 150. [Modes for carrying out the invention]

[0012] <Power conversion device 100> FIG. 1 is a diagram showing a power conversion device 100 according to an embodiment of the present invention. The power conversion device 100 is, for example, a power conversion device installed in an automobile.

[0013] The power conversion device 100 includes a three-phase single-phase matrix converter 110, a high-frequency transformer 120, an AC-DC converter 130, and a control unit 140. The power conversion device 100 also has three AC power terminals IT1, IT2, IT3 (the first AC power terminal IT1, the second AC power terminal IT2, and the third AC power terminal IT3) for connecting to an AC power source (three-phase AC power source 200, single-phase AC power source 300) or a load, and two DC power terminals DT1, DT2 (positive-side DC power terminal DT1, negative-side DC power terminal DT2) for connecting to a battery 400 or a load. The positive-side DC power terminal DT1 is connected to the positive electrode of the battery 400 or the load, and the negative-side DC power terminal DT2 is connected to the negative electrode of the battery 400 or the load.

[0014] As shown in FIG. 2, when the three-phase AC power source 200 is connected to the AC power terminals IT1, IT2, IT3 and the battery 400 is connected to the DC power terminals DT1, DT2, the power conversion device 100 converts the three-phase AC power input from the three-phase AC power source 200 into DC power and outputs it to the battery 400. Also, when a load driven by three-phase AC power is connected to the AC power terminals IT1, IT2, IT3 and the battery 400 is connected to the DC power terminals DT1, DT2, the power conversion device 100 converts the DC power input from the battery 400 into three-phase AC power and outputs it to the load.

[0015] Also, as shown in Fig. 3, when a single-phase AC power supply 300 is connected to the AC power terminals IT1, IT2, and IT3, and a battery 400 is connected to the DC power terminals DT1 and DT2, the power conversion device 100 converts the single-phase AC power input from the single-phase AC power supply 300 into DC power and outputs it to the battery 400. Also, when a load driven by single-phase AC power is connected to the AC power terminals IT1, IT2, and IT3, and the battery 400 is connected to the DC power terminals DT1 and DT2, the power conversion device 100 converts the DC power input from the battery 400 into single-phase AC power and outputs it to the load.

[0016] The three-phase single-phase matrix converter 110 is connected between the AC power terminals IT1, IT2, and IT3 and the high-frequency transformer 120. For example, when an AC power supply (e.g., a commercial AC power supply with a frequency of 50 Hz or 60 Hz) is connected to the AC power terminals IT1, IT2, and IT3, the three-phase single-phase matrix converter 110 converts the AC power input from this AC power supply into high-frequency AC power and outputs the high-frequency AC power to the high-frequency transformer 120.

[0017] As shown in Fig. 1, the three-phase single-phase matrix converter 110 has six switches S11 to S16 (the first switch S11, the second switch S12, the third switch S13, the fourth switch S14, the fifth switch S15, and the sixth switch S16). The switches S11 to S16 are bidirectional switches. For example, as shown in Fig. 4, the switches S11 to S16 are constituted by connecting two switching elements (e.g., IGBTs (Insulated-Gate Bipolar Transistors)) SE1 and SE2 in series with diodes connected in parallel such that the forward directions of the diodes are opposite to each other. The switches S11 to S16 only need to be bidirectional switches and are not limited to the configuration shown in Fig. 4.

[0018] In the example shown in Figure 4, if switching element SE1 is ON and switching element SE2 is OFF, current flows from switching element SE1 to switching element SE2, and current from switching element SE2 to switching element SE1 is limited. If switching element SE2 is ON and switching element SE1 is OFF, current flows from switching element SE2 to switching element SE1, and current from switching element SE1 to switching element SE2 is limited. If both switching elements SE1 and SE2 are ON, current can flow in both directions, and if both switching elements SE1 and SE2 are OFF, bidirectional current is limited.

[0019] The three-phase single-phase matrix converter 110 has five terminals T11 to T15 (the first terminal T11, the second terminal T12, the third terminal T13, the fourth terminal T14, and the fifth terminal T15). The first terminal T11 is connected to the first AC power terminal IT1, the second terminal T12 is connected to the second AC power terminal IT2, and the third terminal T13 is connected to the third AC power terminal IT3. The fourth and fifth terminals T14 and T15 are connected to the high-frequency transformer 120. In other words, the first to third terminals T11 to T13 are connected to an AC power source (three-phase AC power source 200, single-phase AC power source 300) or load via the AC power terminals IT1 to IT3, and three-phase AC power or single-phase AC power is input and output from the first to third terminals T11 to T13. On the other hand, single-phase AC power is input and output from the fourth and fifth terminals T14 and T15. For example, as shown in Figure 2, when a three-phase AC power supply 200 is connected to the AC power terminals IT1 to IT3, three-phase AC power is input to the first to third terminals T11 to T13, and single-phase AC power is output from the fourth and fifth terminals T14 and T15. As shown in Figure 3, when a single-phase AC power supply 200 is connected to two of the AC power terminals IT1 to IT3, single-phase AC power is input to the two terminals connected to those two terminals among the first to third terminals T11 to T13, and single-phase AC power is output from the fourth and fifth terminals T14 and T15.

[0020] A first switch S11 is connected between the first terminal T11 and the fourth terminal T14, a second switch S12 is connected between the first terminal T11 and the fifth terminal T15, a third switch S13 is connected between the second terminal T12 and the fourth terminal T14, a fourth switch S14 is connected between the second terminal T12 and the fifth terminal T15, a fifth switch S15 is connected between the third terminal T13 and the fourth terminal T14, and a sixth switch S16 is connected between the third terminal T13 and the fifth terminal T15.

[0021] The three-phase single-phase matrix converter 110 may be connected to the AC power terminals IT1 to IT3 via an input filter IF, as shown in Figure 1. In other words, the input filter IF may be connected between the AC power terminals IT1 to IT3 and the first to third terminals T11 to T13 of the three-phase single-phase matrix converter 110, as shown in Figure 1. In the example shown in Figure 1, the input filter IF is composed of a resistor, an inductor, and a capacitor.

[0022] The high-frequency transformer 120 is connected between the three-phase single-phase matrix converter 110 and the AC / DC converter 130. For example, when an AC power source is connected to the AC power terminals IT1, IT2, and IT3, the high-frequency transformer 120 converts the voltage of the high-frequency AC power output from the three-phase single-phase matrix converter 110 and outputs the converted high-frequency AC power to the AC / DC converter 130.

[0023] The high-frequency transformer 120 is an isolated transformer and has two windings W21 and W22 (first winding W21 and second winding W22). One side of the first winding W21 is connected to the fourth terminal T14 of the three-phase single-phase matrix converter 110, and the other side of the first winding W21 is connected to the fifth terminal T15 of the three-phase single-phase matrix converter 110. In other words, the first winding W21 is the winding on the three-phase single-phase matrix converter 110 side. On the other hand, the second winding W22 is connected to the AC / DC converter 130. In other words, the second winding W22 is the winding on the AC / DC converter 130 side. The high-frequency transformer 120 has a leakage inductor L21.

[0024] The AC / DC converter 130 is connected between the DC power terminals DT1 and DT2 and the high-frequency transformer 120. For example, if an AC power source is connected to the AC power terminals IT1, IT2, and IT3, and a battery 400 is connected to the DC power terminals DT1 and DT2, the AC / DC converter 130 converts the high-frequency AC power output from the high-frequency transformer 120 into DC power and outputs the DC power to the battery 400.

[0025] As shown in Figure 1, the ACDC converter 130 has four switches S31 to S34 (the first switch S31, the second switch S32, the third switch S33, and the fourth switch S34). The switches S31 to S34 of the ACDC converter 130 are, for example, switching elements (e.g., IGBTs) with diodes connected in parallel.

[0026] The AC / DC converter 130 has two AC power terminals T31 and T32 (first AC power terminal T31, second AC power terminal T32) and two DC power terminals T33 and T34 (positive DC power terminal T33, negative DC power terminal T34). The first AC power terminal T31 is connected to one side of the second winding W22 of the high-frequency transformer 120, and the second AC power terminal T32 is connected to the other side of the second winding W22 of the high-frequency transformer 120. The positive DC power terminal T33 is connected to the positive DC power terminal DT1 of the power converter 100, and the negative DC power terminal T34 is connected to the negative DC power terminal DT2 of the power converter 100. In other words, the positive DC power terminal T33 is connected to the positive side of the battery 400 or load via the positive DC power terminal DT1, and the negative DC power terminal T34 is connected to the negative side of the battery 400 or load via the negative DC power terminal DT2. DC power is input and output from the positive DC power terminal T33 and the negative DC power terminal T34. On the other hand, single-phase AC power is input and output from the two AC power terminals T31 and T32. For example, if a three-phase AC power supply 200 is connected to the AC power terminals IT1 to IT3 as shown in Figure 2, or if a single-phase AC power supply 200 is connected to two of the AC power terminals IT1 to IT3 as shown in Figure 3, high-frequency single-phase AC power is input to the AC power terminals T31 and T32, and DC power is output from the DC power terminals T33 and T34.

[0027] The four switches S31 to S34 constitute a full bridge circuit, with the first switch S31 connected between the first AC power terminal T31 and the positive DC power terminal T33, the second switch S32 connected between the first AC power terminal T31 and the negative DC power terminal T34, the third switch S33 connected between the second AC power terminal T32 and the positive DC power terminal T33, and the fourth switch S34 connected between the second AC power terminal T32 and the negative DC power terminal T34.

[0028] The AC / DC converter 130 may be connected to the DC power terminals DT1 and DT2 of the power converter 100 via an output filter OF, as shown in Figure 1. In other words, the output filter OF may be connected between the DC power terminals T33 and T34 of the AC / DC converter 130 and the DC power terminals DT1 and DT2 of the power converter 100, as shown in Figure 1. In the example shown in Figure 1, the output filter OF is composed of a resistor, an inductor, and a capacitor.

[0029] The control unit 140 controls switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130. The control unit 140 is configured, for example, by a computer.

[0030] As described above, the power conversion device 100 according to this embodiment includes a three-phase single-phase matrix converter 110, a high-frequency transformer 120, and an AC / DC converter 130. Therefore, it is possible to convert three-phase AC power to DC power and output DC power, or to convert DC power to three-phase AC power and output three-phase AC power.

[0031] As shown in Figure 3, when a single-phase AC power supply 300 is connected to two of the three AC power terminals IT1 to IT3 (in the example shown in Figure 3, AC power terminals IT1 and IT3), single-phase AC power is input to the three-phase single-phase matrix converter 110. The input power value from the three-phase AC power supply 200 is constant, but the instantaneous power value pin of the input power from the single-phase AC power supply 300 pulsates as shown in Figure 5. The instantaneous power value pin(t) of the input power from the single-phase AC power supply 300 is the sum of the average power value Pin and the pulsating portion prip(t) of the input power from the single-phase AC power supply 300, as shown below, and pulsates around the average power value Pin (dashed line in Figure 5), as shown by the solid line in Figure 5.

number

[0032] Therefore, the power converter 100 according to this embodiment further includes a power pulsation compensation circuit 150 to compensate for this pulsation. The power pulsation compensation circuit 150 includes an inductor L51, a capacitor Cbuf, a first terminal T51, and a second terminal T52, and the inductor L51 and the capacitor Cbuf are connected in series between the first terminal T51 and the second terminal T52. In the example shown in Figure 1, the inductor L51 is connected to the first terminal T51 side, and the capacitor Cbuf is connected to the second terminal T52 side. The first terminal T51 is connected to the center tap of the second winding W22 (coil on the AC / DC converter 130 side) of the high-frequency transformer 120, and the second terminal T52 is connected to the negative side DC power terminal T34 of the AC / DC converter 130 (i.e., the negative side of the AC / DC converter 130). In other words, the power pulsation compensation circuit 150 is connected between the center tap of the second winding W22 of the high-frequency transformer 120 (the coil on the AC / DC converter 130 side) and the negative-side DC power terminal T34 of the AC / DC converter 130 (i.e., the negative side of the AC / DC converter 130).

[0033] Then, when the single-phase AC power supply 300 is connected to the AC power terminals IT1 to IT3 (that is, when the single-phase AC power supply 300 is connected to the three-phase single-phase matrix converter 110), the control unit 140 controls the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130, thereby compensating the pulsation of the input power pin from the single-phase AC power supply 300 using the capacitor Cbuf of the power pulsation compensation circuit 150, and keeping the output voltage Vout output from the power converter 100 constant.

[0034] At this time, in the power conversion device 100 according to the present embodiment, when the instantaneous power value pin of the input power input from the single-phase AC power supply 300 is higher than the average power value Pin of this input power (pin > Pin), and when the instantaneous power value pin of the input power input from the single-phase AC power supply 300 is lower than the average power value Pin of this input power (pin < Pin), the control is changed. At this time, as shown in FIG. 6, the control unit 140 controls the switching of the switches S11 to S16 of the three-phase single-phase matrix converter 110 and the switches S31 to S34 of the ACDC converter 130 so as to include a period during which the voltage difference between the first terminal T31 and the second terminal T32 of the ACDC converter 130, that is, the voltage value of the voltage (input voltage v2 (thick line in FIG. 6)) input to the ACDC converter 130 becomes zero (zero voltage period). During this zero voltage period, no power transmission is performed from the three-phase single-phase matrix converter 110 side to the ACDC converter 130 side.

[0035] For example, when the instantaneous power value pin of the input power input from the single-phase AC power supply 300 is higher than the average power value Pin (pin > Pin), the control unit 140 controls the switches S31 and S33 (that is, the switches on the positive electrode side of the ACDC converter) of the ACDC converter 130 to be turned on and the switches S32 and S34 (that is, the switches on the negative electrode side of the ACDC converter 130) to be turned off during this zero voltage period, as shown in FIG. 7, and charges the capacitor Cbuf of the power pulsation compensation circuit 150 with the pulsation part prip of the instantaneous power value pin of the input power input from the single-phase AC power supply 300 so that a certain amount of power is output from the power conversion device 100. That is, in the present embodiment, the period during which the instantaneous power value pin of the input power input from the single-phase AC power supply 300 is higher than the average power value Pin is the period (charging period) during which the capacitor Cbuf is charged, and the instantaneous power value pbuf of the power output from the capacitor Cbuf becomes negative as shown by the dashed-dotted line in FIG. 5.

[0036] On the one hand, when the instantaneous power value pin of the input power input from the single-phase AC power supply 300 is lower than the average power value Pin (pin < Pin), during the zero voltage period, as shown in FIG. 8, the control unit 140 controls the switches S31 and S33 of the ACDC converter 130 (that is, the switches on the positive electrode side of the ACDC converter) to be turned off, and controls the switches S32 and S34 of the ACDC converter 130 (that is, the switches on the negative electrode side of the ACDC converter 130) to be turned on, discharges the capacitor Cbuf, and compensates for the pulsating part prip, which is the difference between the instantaneous power value pin of the input power input from the single-phase AC power supply 300 and the average power value Pin, with the power pbuf output from this capacitor Cbuf, so that a constant power is output from the power conversion device 100. That is, in the present embodiment, the period during which the instantaneous power value pin of the input power input from the single-phase AC power supply 300 is lower than the average power value Pin is the period (discharge period) during which the capacitor Cbuf discharges, and the instantaneous power value pbuf of the power output from the capacitor Cbuf becomes positive, as shown by the dashed-dotted line in FIG. 5.

[0037] As described above, in the present embodiment, the control unit 140 controls the switching of the switches S31 to S34 of the ACDC converter 130 during the zero voltage period so that the sum of the instantaneous power value pin of the input power input from the single-phase AC power supply 300 and the instantaneous power value pbuf of the power output from the capacitor Cbuf (that is, the output voltage Pout from the power conversion device 100) is constant, and charges and discharges the capacitor Cbuf.

[0038] Therefore, in the present embodiment, it is possible to convert single-phase AC power into DC power with compensated pulsation using the three-phase single-phase matrix converter 110. As a result, in the present embodiment, a DC link converter is not required, and a small-sized power conversion device can be provided. The capacitor Cbuf of the power pulsation compensation circuit 150 may have a significantly smaller capacitance than the DC link capacitor used in a conventional charger, and can be constituted by a long-life film capacitor.

[0039] Furthermore, in this embodiment, by changing the direction of power transmission, it is possible to convert the DC power stored in the battery 400 into single-phase AC power. For this reason, the power conversion device 100 according to this embodiment is also compatible with so-called V2X (Vehicle to X) technology.

[0040] <Parameters for switching control> As described above, the control unit 140 controls the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130, including a zero-voltage period, as shown in Figure 6. At this time, the switching control by the control unit 140 is determined based on the instantaneous voltage value vin of the input voltage input from the single-phase AC power supply 300, the frequency ωin of the input voltage input from the single-phase AC power supply 300, the instantaneous power value pin of the input power input from the single-phase AC power supply 300, the output voltage Vout to the battery 400, the turns ratio N of the high-frequency transformer 120 (= (number of turns n1 of winding W21) / (number of turns n2 of winding W22)), the inductance value Lleak of the leakage inductor L21 of the high-frequency transformer 120, the target output voltage value vbuf from the capacitor Cbuf of the power pulsation compensation circuit 150, the phase difference δ between the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and the switching of switches S31 to S34 of the AC / DC converter 130, and the length of the zero-voltage period 2ε. As shown in Figure 6, the phase difference δ is also the phase difference between the output voltage v1 output from the three-phase single-phase matrix converter 110 and the input voltage v2 input to the AC / DC converter 130.

[0041] Here, the length of the zero-voltage period 2ε is calculated as follows, based on the output voltage value Vout and the target output voltage value vbuf from the capacitor Cbuf.

number

number

[0042] Figure 6 shows not only the input voltage v1 of the ACDC converter 130, but also the voltage difference between the fourth terminal T14 and the fifth terminal T15 of the three-phase single-phase matrix converter 110, that is, the voltage output from the three-phase single-phase matrix converter 110 (output voltage v1 (dashed line in Figure 6)). If the phase difference δ is not longer than the length of the zero-voltage period 2ε, then, as shown in Figure 6, there is a portion where the zero-voltage period of the output voltage v1 of the three-phase single-phase matrix converter 110 and the zero-voltage period of the ACDC converter 130 overlap.

[0043] However, as the length of the zero-voltage period 2ε decreases and the phase difference δ becomes longer than the length of the zero-voltage period 2ε, the zero-voltage period of the output voltage v1 of the three-phase single-phase matrix converter 110 and the zero-voltage period of the AC / DC converter 130 no longer overlap, as shown in Figure 9. If switching control is performed during this period based on the value of the phase difference δ calculated using equation (2), an error will occur in the transmitted power.

[0044] Therefore, in this embodiment, the control unit 140 changes the method for calculating the value of the phase difference δ used when generating the switching patterns of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130, based on whether or not the phase difference δ is longer than the length of the zero-voltage period 2ε.

[0045] Specifically, if the phase difference δ is not longer than the zero-voltage period length 2ε (δ ≤ 2ε), the control unit 140 calculates the phase difference δ using the above equation (2), generates switching patterns for switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130 based on the calculated phase difference δ, and controls the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130 using the generated switching patterns.

[0046] On the other hand, if the phase difference δ is longer than the length of the zero-voltage period 2ε (δ>2ε), the control unit 140 calculates the phase difference δ using the following equation (3) based on the instantaneous voltage value vin of the input voltage, the frequency ωin of the input voltage, the instantaneous power value pin of the input power, the output voltage value Vout, the turns ratio N, the leakage inductance value Lleak, the target output voltage value vbuf from the capacitor Cbuf of the power pulsation compensation circuit 150, and the length of the zero-voltage period 2ε.

number

[0047] Therefore, in this embodiment, the output voltage Vout output to the battery 400 is smoothed. As a result, efficient charging is possible while suppressing heat generation and degradation of the battery 400. Furthermore, in this embodiment, by changing the direction of power transmission, it is possible to convert the DC power stored in the battery 400 into single-phase AC power. At this time, the single-phase AC power output from the power converter 100 according to this embodiment is also smoothed. As a result, in this embodiment, efficient discharge is possible while suppressing heat generation and degradation of the battery 400.

[0048] <Processing operations in the control unit 140> Figure 10 shows an example of a processing operation performed in the control unit 140. The processing operation shown in Figure 10 is performed, for example, at predetermined time intervals.

[0049] The control unit 140 obtains the instantaneous input voltage value vin, the instantaneous input power value pin, and the output voltage value Vout (step S1001). Based on the obtained instantaneous input voltage value vin, the instantaneous input power value pin, and the output voltage value Vout, it calculates the target output voltage value vbuf from capacitor Cbuf. Based on the obtained instantaneous input voltage value vin and the calculated target output voltage value vbuf, it calculates the length of the zero voltage period 2ε using equation (1) above (step S1002). The control unit 140 calculates the phase difference δ using equation (2) above (step S1003).

[0050] If the phase difference δ is not longer than the length of the zero-voltage period 2ε (step S1004, NO), the control unit 140 generates switching patterns for switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130 based on the phase difference δ calculated using equation (2) above (step S1005), and uses the generated switching patterns to control the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130 (step S1006).

[0051] If the phase difference δ is longer than the zero-voltage period length 2ε (step S1004, YES), the control unit 140 calculates the phase difference δ using the above equation (3) (step S1007), generates switching patterns for switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130 based on the phase difference δ calculated using the above equation (3) (step S1008), and uses the generated switching patterns to control the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC / DC converter 130 (step S1006).

[0052] <Control when connecting a 20V three-phase AC power supply> As shown in Figure 2, when a three-phase AC power supply 200 is connected to the three AC power terminals IT1 to IT3, three-phase AC power is input to the three-phase single-phase matrix converter 110. Since the input power value from the three-phase AC power supply 200 is constant, unlike the input power from the single-phase AC power supply 300, the instantaneous power value pin does not pulsate, and there is no need for pulsation compensation by the power pulsation compensation circuit 150. Even when a single-phase AC power supply 300 is connected to the three AC power terminals IT1 to IT3, if the control unit 140 controls the switching of switches S11 to S16 of the three-phase single-phase matrix converter 110 and switches S31 to S34 of the AC-DC converter 130 so as shown in Figure 11 that the voltage value of the voltage input to the AC-DC converter 130 (input voltage v2) is zero (zero voltage period), charging and discharging of the capacitor Cbuf of the power pulsation compensation circuit 150 occurs during this zero voltage period, and this charging and discharging may affect the output voltage Vout output from the power converter 100. In the example shown in Figure 11, t0~t1, t2~t3, t4~t5, t6~t7, and t8~t9 are zero-voltage periods. Figure 11 also shows the switching of switches S31~S34 of the ACDC converter 130 when the switching of switches S11~S16 of the three-phase single-phase matrix converter 110 and switches S31~S34 of the ACDC converter 130 is controlled to include the zero-voltage period. In the example shown in Figure 11, the switching control of switches S31~S34 of the ACDC converter 130 is a repetition of the switching control between t1 and t5.

[0053] When the positive-side switch of the ACDC converter (switches S31 and S33 of the ACDC converter 130) is ON, or when the negative-side switch of the ACDC converter 130 (switches S32 and S34 of the ACDC converter 130) is ON, the voltage value of the voltage input to the ACDC converter 130 becomes zero. In other words, during the zero-voltage period, either the positive-side switch of the ACDC converter (switches S31 and S33 of the ACDC converter 130) or the negative-side switch of the ACDC converter 130 (switches S32 and S34 of the ACDC converter 130) is ON. As described above, when the positive terminal switch of the ACDC converter (switches S31 and S33 of the ACDC converter 130) is turned ON and the negative terminal switch of the ACDC converter 130 (switches S32 and S34 of the ACDC converter 130) is turned OFF, the capacitor Cbuf of the power pulsation compensation circuit 150 is charged, as shown in Figure 7. When the positive terminal switch of the ACDC converter (switches S31 and S33 of the ACDC converter 130) is turned OFF and the negative terminal switch of the ACDC converter 130 (switches S32 and S34 of the ACDC converter 130) is turned ON, the capacitor Cbuf is discharged, as shown in Figure 8.

[0054] Therefore, as shown in Figure 11, if the positive terminal switches of the ACDC converter (switches S31 and S33 of the ACDC converter 130) are controlled to always be on during the zero-voltage period, then during the zero-voltage period, there is a period when the positive terminal switches of the ACDC converter (switches S31 and S33 of the ACDC converter 130) are on and the negative terminal switches of the ACDC converter 130 (switches S32 and S34 of the ACDC converter 130) are off (i.e., a charging period), while there is no period when the negative terminal switches of the ACDC converter 130 (switches S32 and S34 of the ACDC converter 130) are on and the positive terminal switches of the ACDC converter (switches S31 and S33 of the ACDC converter 130) are off (i.e., a discharge period). As a result, the capacitor Cbuf continues to be charged and does not discharge.

[0055] Therefore, if a three-phase AC power supply 200 is connected to the three AC power terminals IT1 to IT3, the control unit 140 should control switches S31 to S34 of the AC-CDC converter 130 such that, during the zero-voltage period, the period in which the positive-side switches of the AC-CDC converter (switches S31 and S33 of the AC-CDC converter 130) are on and the negative-side switches of the AC-CDC converter 130 (switches S32 and S34 of the AC-CDC converter 130) are off (i.e., the charging period) is equal to the period in which the negative-side switches of the AC-CDC converter 130 (switches S32 and S34 of the AC-CDC converter 130) are on and the positive-side switches of the AC-CDC converter (switches S31 and S33 of the AC-CDC converter 130) are off (i.e., the discharge period) (for example, Figure 12). In the example shown in Figure 12, the switching control of switches S31 to S34 of the AC / DC converter 130 is repeated between t1 and t9. In the example shown in Figure 12, during the zero-voltage period (t2 to t3, t4 to t5, t6 to t7, t8 to t9) between t1 and t9, the charging period (t6 to t7, t8 to t9) is equal to the discharge period (t2 to t3, t4 to t5).

[0056] In this way, the charging period of capacitor Cbuf and the discharging period of capacitor Cbuf become equal, the average charging and discharging power of capacitor Cbuf in the power pulsation compensation circuit 150 becomes zero, and it becomes possible to keep the voltage of the power pulsation compensation circuit 150 nearly constant. As a result, it becomes possible to reduce the influence of charging and discharging of capacitor Cbuf in the power pulsation compensation circuit 150 on the output voltage Vout output from the power converter 100.

[0057] <Switch S51 of power pulsation compensation circuit 150> The power pulsation compensation circuit 150 may further include a switch S51, as shown in Figure 13. As shown in Figure 13, the switch S51 is connected in series with an inductor L51 and a capacitor Cbuf between a first terminal T51 (i.e., the center tap of the second winding W22 of the high-frequency transformer 120 (the coil on the AC / DC converter 130 side)) and a second terminal T52 (i.e., the negative-side DC power terminal T34 of the AC / DC converter 130 (i.e., the negative side of the AC / DC converter 130)). In the example shown in Figure 13, the switch S51 is connected between the first terminal T51 and the inductor L51. The switch S51 may be a relay, or, as shown in Figure 4, it may be configured by connecting two switching elements SE1 and SE2, each with diodes in parallel, in series such that the forward directions of the diodes are opposite to each other. Furthermore, the control unit 140 should be configured to turn off switch S51 when the three AC power terminals IT1 to IT3 are connected to the three AC power terminals.

[0058] This method prevents the influence of charging and discharging of the capacitor Cbuf in the power pulsation compensation circuit 150 on the output voltage Vout output from the power converter 100. It also prevents unnecessary power loss in the power pulsation compensation circuit 150.

[0059] In this case, the control unit 140 may detect that the three-phase AC power supply 200 is connected to the three AC power terminals IT1 to IT3 by the voltage of the AC power terminals IT1 to IT3, or it may detect this by external communication or commands.

[0060] The present invention has been described above with reference to preferred embodiments. Although the present invention has been described with reference to specific examples, various modifications and changes can be made to these examples without departing from the spirit and scope of the invention as described in the claims. [Explanation of Symbols]

[0061] 100 Power converter 110 Three-phase single-phase matrix converter S11~S16 Switches for the three-phase single-phase matrix converter 110 120 High-frequency transformer L21 Leakage inductor of high-frequency transformer 120 W21 Winding on the three-phase single-phase matrix converter 110 side of the high-frequency transformer 120 W22 Winding on the AC / DC converter 130 side of high-frequency transformer 120 130 AC / DC Converters S31~S34 Switch of AC / DC converter 130 140 Control Unit 150 Power pulsation compensation circuit Cbuf capacitor in power pulsation compensation circuit 150 S51 Power pulsation compensation circuit 150 switch 200 Three-phase AC power supply 300 Single-phase AC power supply 400 batteries IF Input Filter OF output filter

Claims

1. A three-phase single-phase matrix converter, ADC converter and A transformer connected between the three-phase single-phase matrix converter and the ADC converter, A power pulsation compensation circuit having an inductor and a capacitor connected in series, The aforementioned power pulsation compensation circuit is, A power conversion device connected between the center tap of the winding on the ADC converter side of the transformer and the negative terminal side of the ADC converter.

2. The system further includes a control unit that controls the switches of the three-phase single-phase matrix converter and the switches of the ACDC converter, The control unit, The power conversion device according to claim 1, wherein when a single-phase AC power supply is connected to the three-phase single-phase matrix converter, the switches of the three-phase single-phase matrix converter and the switches of the ADC converter are controlled to compensate for the pulsation of the input power input from the single-phase AC power supply using the capacitor of the power pulsation compensation circuit.

3. The control unit, During the charging period in which the instantaneous power value of the power input from the single-phase AC power supply is higher than the average power value of the power input from the single-phase AC power supply, the switch of the ADC converter is controlled so that the capacitor of the power pulsation compensation circuit is charged. The power conversion device according to claim 2, wherein the switch of the ADC converter is controlled to discharge the power charged in the capacitor of the power pulsation compensation circuit during a discharge period in which the instantaneous power value of the power input from the single-phase AC power supply is lower than the average power value of the power input from the single-phase AC power supply.

4. The control unit, The power conversion device according to claim 3, wherein the switches of the three-phase single-phase matrix converter and the switches of the ADC converter are controlled such that the input voltage input from the transformer to the ADC converter includes a zero-voltage period.

5. The control unit, The power conversion device according to claim 4, wherein during the charging period, the switch on the positive terminal side of the ACDC converter is controlled to be ON, and the switch on the negative terminal side of the ACDC converter is controlled to be OFF during the zero voltage period.

6. The control unit, The power conversion device according to claim 4 or 5, wherein during the discharge period, the switch on the positive electrode side of the ACDC converter is controlled to be off and the switch on the negative electrode side of the ACDC converter is controlled to be on during the zero voltage period.

7. The power conversion device described in claim 1 is installed in an automobile.

8. The control unit, The power conversion device according to claim 4, wherein when a three-phase AC power supply is connected to the three-phase single-phase matrix converter, the switches of the ADC converter are controlled such that, during the zero-voltage period, the period in which the positive-side switch of the ADC converter is on and the negative-side switch of the ADC converter is off is equal to the period in which the negative-side switch of the ADC converter is on and the positive-side switch of the ADC converter is off.

9. The aforementioned power pulsation compensation circuit is, The power conversion device according to claim 2, further comprising a switch connected in series with the inductor and the capacitor.

10. The control unit, The power conversion device according to claim 9, wherein if a three-phase AC power supply is connected to the three-phase single-phase matrix converter, the power pulsation compensation circuit is controlled to be switched off.

11. A control method for controlling a power converter, which is performed by a computer, The aforementioned power converter is A three-phase single-phase matrix converter, ADC converter and A transformer connected between the three-phase single-phase matrix converter and the ADC converter, A power pulsation compensation circuit having an inductor and a capacitor connected in series, The aforementioned power pulsation compensation circuit is, It is connected between the center tap of the winding on the ADC converter side of the transformer and the negative terminal side of the ADC converter. The control method described above is A control method comprising the step of controlling the switches of the three-phase single-phase matrix converter and the switches of the ADC converter so as to compensate for the pulsation of the input power input from the single-phase AC power supply using the capacitor of the power pulsation compensation circuit when a single-phase AC power supply is connected to the three-phase single-phase matrix converter.

12. A control program that causes a computer to execute the control method described in claim 11.

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