JP2015100200A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bidirectional power conversion device that attains both improvement of power conversion efficiency and reduction in cost.SOLUTION: A power conversion device includes: a capacitor 16 connected to connection terminals 21a and 21b; a full-bridge circuit 15 connected to the connection points of the connection terminals 21a and 21b and the capacitor 16; a filter circuit 12 connected to connection terminals 11a and 11b; a half-bridge circuit 13 connected to the connection points of the connection terminals 11a and 11b and the filter circuit 12; a reactor 14 connected between middle points of each bridge of the full-bridge circuit 15 and the half-bridge circuit 13; a voltage sensor 19 detecting a DC voltage applied between the DC-side connection terminals 21a and 21b; a voltage sensor 17 detecting an AC voltage applied between the AC-side connection terminals 11a and 11b; and a control device switchingly controlling switching elements Q3 to Q6 included in the full-bridge circuit and reverse-blocking IGBTs Q1p, Q1n, Q2p, and Q2n included in the half-bridge circuit.

Description

  The present invention relates to a power conversion device that converts AC power to DC power, or DC power to AC power.

  Patent Document 1 discloses a diode bridge circuit that full-wave rectifies an AC voltage, a DC load connected between a positive output terminal and a negative output terminal of the diode bridge circuit, and the positive output terminal and the DC load. A power conversion device including a direct current reactor connected between and an input side transistor connected between the positive output terminal and the direct current reactor is described. The power conversion device described in Patent Literature 1 is further connected between the input side short circuit diode connected to the connection point of the input side transistor and the DC reactor and the negative output terminal, and the reactor and the DC load. The output side diode is provided, The output side transistor connected to the connection point of a direct current reactor and an output side diode, and the said negative electrode side output terminal.

  In the power converter of Patent Document 1, in order to store energy in a DC reactor when converting AC power to DC power, two diodes included in the diode bridge circuit, an input side transistor, and an output side short-circuit transistor These four elements are made conductive. Therefore, conduction loss occurs in the four elements, and the efficiency of converting AC power into DC power is reduced.

  Patent Literature 2 describes a power conversion device that has improved power conversion efficiency over the power conversion device of Patent Literature 1. The power conversion device of Patent Document 2 includes four reverse-blocking IGBTs, which steps down and rectifies AC power, a reactor connected between the bridge circuit and a DC load, a reactor and DC And a diode connected between the load and an IGBT connected between the connection point between the reactor and the diode and the DC load. In the power conversion device of Patent Document 2, when AC power is converted to DC power, the bridge circuit reduces the voltage and rectifies the current, thereby reducing the number of elements to be conducted to three and improving the power conversion efficiency.

Japanese Utility Model Publication No. 5-18287 JP 2012-217294 A

  When making the power converter device of patent document 2 into a bidirectional | two-way type power converter device, it is necessary to carry out reverse parallel connection of the reverse blocking IGBT with respect to each of four reverse blocking IGBTs. That is, eight reverse blocking IGBTs are required. As the reverse blocking IGBT increases, it is necessary to add a driver for driving the reverse blocking IGBT. Therefore, the cost increases when the bidirectional power converter is used.

  In view of the above circumstances, the present invention has as its main object to provide a bidirectional power conversion device that achieves both improved power conversion efficiency and reduced cost.

  In order to solve the above-mentioned problem, the present invention is a power converter, and is connected to a smoothing capacitor connected to a pair of DC side connection terminals, and a connection point between the pair of DC side connection terminals and the smoothing capacitor. A full bridge circuit composed of four switching elements, a filter circuit connected to a pair of AC side connection terminals, and a connection point between the pair of AC side connection terminals and the filter circuit, and mutually opposite A half-bridge circuit configured by connecting two pairs of reverse-blocking IGBTs connected in parallel in series, the middle of each bridge of the full-bridge circuit, and both ends of the pair of reverse-blocking IGBTs of the half-bridge circuit A reactor connected to each other, DC voltage detecting means for detecting a DC voltage applied between the pair of DC side connection terminals, and the pair of AC side connection AC voltage detection means for detecting an AC voltage applied between the terminals, current detection means for detecting a current flowing through the reactor, the DC voltage detection means, the AC voltage detection means, and detection values of the current detection means And a control device that performs switching control of the four switching elements included in the full-bridge circuit and the four reverse blocking IGBTs included in the half-bridge circuit.

  According to the present invention, when a DC load is connected between a pair of DC side connection terminals, an AC power source is connected between the pair of AC side terminals, and a current is passed from the AC power source to the DC load, the half bridge circuit The voltage is stepped down and boosted and rectified by a full bridge circuit. At this time, one reverse blocking IGBT included in the half-bridge circuit and two elements included in the full-bridge circuit are brought into conduction.

  When a DC power source is connected between a pair of DC side connection terminals, an AC load is connected between a pair of AC side terminals, and a current is passed from the DC power source to the AC load, the voltage is reduced and rectified by a full bridge circuit. The voltage is boosted by the half bridge circuit. At this time, the two elements included in the full bridge circuit and the one reverse blocking IGBT included in the half bridge circuit are brought into conduction.

  Therefore, conduction loss can be reduced when power is converted bidirectionally. Further, since the half bridge circuit is composed of four reverse blocking IGBTs, a bidirectional power conversion circuit can be realized at low cost. Therefore, it is possible to convert power in both directions while achieving both improvement in power conversion efficiency and cost reduction.

The figure which shows the structure of the power converter device which concerns on 1st-3rd and 7th-9th embodiment. The figure which shows the on-off timing of the alternating voltage in 1st Embodiment, DC voltage, and each switching element. The figure which shows the flow of the electric current in 1st Embodiment. The figure which shows the flow of the electric current in 1st Embodiment. The figure which shows the on-off timing of the alternating voltage in a 2nd Embodiment, a DC voltage, and each switching element. The figure which shows the flow of the electric current in 2nd Embodiment. The figure which shows the flow of the electric current in 2nd Embodiment. The figure which shows the on-off timing of the alternating voltage in a 3rd embodiment, direct-current voltage, and each switching element. The figure which shows the flow of the electric current in 3rd Embodiment. The figure which shows the flow of the electric current in 3rd Embodiment. The figure which shows the structure of the power converter device which concerns on 4th-6th embodiment. The figure which shows the on-off timing of the alternating voltage in 4th Embodiment, a DC voltage, and each switching element. The figure which shows the flow of the electric current in 4th Embodiment. The figure which shows the flow of the electric current in 4th Embodiment. The figure which shows the on-off timing of the alternating voltage in a 5th Embodiment, a DC voltage, and each switching element. The figure which shows the flow of the electric current in 5th Embodiment. The figure which shows the flow of the electric current in 5th Embodiment. The figure which shows the on-off timing of the alternating voltage in a 6th Embodiment, DC voltage, and each switching element. The figure which shows the flow of the electric current in 6th Embodiment. The figure which shows the flow of the electric current in 6th Embodiment. The figure which shows the on-off timing of the alternating voltage in a 7th Embodiment, a DC voltage, and each switching element. The figure which shows the flow of the electric current in 7th Embodiment. The figure which shows the flow of the electric current in 7th Embodiment. The figure which shows the on-off timing of the alternating voltage in FIG. 8, DC voltage, and each switching element. The figure which shows the flow of the electric current in 8th Embodiment. The figure which shows the flow of the electric current in 8th Embodiment. The figure which shows the on-off timing of the alternating voltage in a 9th Embodiment, a DC voltage, and each switching element. The figure which shows the flow of the electric current in 9th Embodiment. The figure which shows the flow of the electric current in 9th Embodiment. The figure which shows the DC voltage in 10th Embodiment, and the on-off timing of each switching element. The figure which shows the flow of the electric current in 10th Embodiment. The figure which shows the flow of the electric current in 10th Embodiment. The figure which shows the DC voltage in 11th Embodiment, and the on-off timing of each switching element. The figure which shows the flow of the electric current in 11th Embodiment. The figure which shows the flow of the electric current in 11th Embodiment. The figure which shows the DC voltage in 12th Embodiment, and the on-off timing of each switching element. The figure which shows the flow of the electric current in 12th Embodiment. The figure which shows the flow of the electric current in 12th Embodiment. The figure which shows the on-off timing of switching element Q2p and Q2n. The figure which shows the structure of the power converter device which concerns on other embodiment. The figure which shows the structure of the power converter device which concerns on other embodiment. The figure which shows the structure of the power converter device which concerns on other embodiment. The figure which shows the structure of the power converter device which concerns on other embodiment.

  Hereinafter, embodiments embodying a bidirectional power converter will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
The structure of the power converter device which concerns on FIG. 1 at 1st-3rd and 7th-12th embodiment is shown. The power conversion device 40 includes a filter circuit 12, a half bridge circuit 13, a reactor 14, a full bridge circuit 15, a smoothing capacitor 16, a voltage sensor 17, a current sensor 18, a voltage sensor 19, and a control device 30. The AC power supply 10 is connected to the AC side connection terminals 11a and 11b of the power converters according to the above embodiments, and the DC load 20 is connected to the DC side connection terminals 21a and 21b.

  The filter circuit 12 is a low-pass filter connected to the pair of AC side connection terminals 11a and 11b. The pair of AC side connection terminals 11a and 11b includes a positive side AC side connection terminal 11a and a negative side AC side connection terminal 11b. The smoothing capacitor 16 is connected to the pair of DC side connection terminals 21a and 21b, and smoothes the voltage between the pair of DC side connection terminals 21a and 21b. The pair of DC side connection terminals 21a and 21b includes a positive side DC side connection terminal 21a and a negative side DC side connection terminal 21b.

  The half bridge circuit 13 is connected to each connection point between the pair of AC side connection terminals 11 a and 11 b and the filter circuit 12. The half-bridge circuit 13 includes switching elements Q1p, Q1n, Q2p, and Q2n that are four reverse blocking IGBTs (insulated gate bipolar transistors). Specifically, two pairs of switching elements Q1p (first IGBT) and Q1n (third IGBT), Q2p (second IGBT), and Q2n (fourth IGBT) connected in antiparallel to each other are connected in series. Connected and configured. The collector terminal of the switching element Q1p is connected to the positive AC side connection terminal 11a, and the emitter terminal of the switching element Q2p is connected to the negative AC side connection terminal 11b. The emitter terminal of the switching element Q1p and the collector terminal of the switching element Q2p are connected.

  The full bridge circuit 15 is connected to each connection point between the pair of DC side connection terminals 21 a and 21 b and the smoothing capacitor 16. The full bridge circuit 15 includes four switching elements Q3 to Q6. The switching elements Q3 to Q6 are each composed of T3 to T6, which are N-type MOSFETs, and diodes D3 to D6 connected in antiparallel.

  The drain terminal of the switching element Q3 (first switching element) and the drain terminal of the switching element Q5 (third switching element) are connected to the DC side connection terminal 21a on the positive electrode side. The source terminal of the switching element Q4 (second switching element) and the source terminal of the switching element Q6 (fourth switching element) are connected to the DC side connection terminal 21b on the negative electrode side. The switching element Q3 and the switching element Q4 are connected in series, and the switching element Q5 and the switching element Q6 are connected in series.

  Reactor 14 includes reactors 14a and 14b connected between the middle of each bridge of full bridge circuit 15 and both ends of a pair of switching elements Q2p and Q2n included in half bridge circuit 13, respectively. Specifically, the reactor 14a is connected to a connection point between the switching element Q3 and the switching element Q4 and a connection point between the switching element Q1p and the switching element Q2p. Reactor 14b is connected to a connection point between switching element Q5 and switching element Q6 and an emitter terminal of switching element Q2p.

  The voltage sensor 17 (AC voltage detecting means) detects an AC voltage applied between the AC side connection terminals 11a and 11b. The voltage sensor 19 (DC voltage detection means) detects a voltage between both electrodes of the smoothing capacitor 16, that is, a DC voltage applied between the DC side connection terminals 21a and 21b. Current sensor 18 (current detection means) detects a current flowing through reactor 14, more specifically, a current flowing between a connection point between switching element Q5 and switching element Q6 and reactor 14b.

  The control device 30 is configured as a microcomputer including a CPU, a memory, an I / O, and the like. The control device 30 performs a charging process in which the AC power of the AC power supply 10 is converted to DC power and supplied to the DC load 20. Specifically, control device 30 performs switching control of switching elements Q1p, Q1n, Q2p, Q2n, and Q3-6 based on detection values of voltage sensor 17, current sensor 18, and voltage sensor 19.

  Next, the charging process will be described in detail with reference to FIGS. FIG. 2A is a time chart showing changes in the AC voltage Vac and the output voltage Vo supplied to the DC load 20. 2B to 2I are time charts showing on / off timings of the switching elements Q1p, Q1n, Q2p, Q2n, Q3, Q4, Q5, and Q6. FIGS. 3A to 3C are circuit diagrams showing the flow of current when the AC voltage Vac ≧ 0, and FIGS. 4A to 4C show the current when the AC voltage Vac <0. It is a circuit diagram which shows a flow.

  In the first embodiment, the step-down control is always performed by switching the switching elements Q1p and Q1n. Further, the switching elements Q4 and Q6 are switched to always perform boosting control and PFC (Power Factor Correction) control.

  As shown in FIG. 2, when the polarity of the AC voltage is positive (Vac ≧ 0), the switching element Q2n is always turned on. Further, the switching element Q1p is switched at the duty ratio DR1 (first duty ratio), and the switching element Q4 is switched at the duty ratio DR2 (second duty ratio). On the other hand, when the polarity of the AC voltage is negative (Vac <0), the switching element Q2p is always turned on. Further, the switching element Q1n is switched at the duty ratio DR1, and the switching element Q6 is switched at the duty ratio DR2.

  The duty ratio DR1 is set to kVo / | Vac | (0.9 ≦ k ≦ 1.0). The duty ratio DR2 is a value calculated based on DC voltage feedback control having reactor current control in a minor loop. Specifically, the target reactor current is set so that the voltage deviation between the target DC voltage and the DC voltage detected by the voltage sensor 19 approaches zero. Further, the duty ratio DR2 is calculated so that the reactor current is subjected to feedback control and feedforward control. The reactor current feedback control is a control for causing the current deviation between the target reactor current and the reactor current detected by the current sensor 18 to approach zero. The reactor current feedforward control is a control capable of rapidly increasing the reactor current without depending on the current deviation. The calculated duty ratio DR2 decreases as | Vac | increases. PFC control can be realized by switching the switching elements Q4 and Q6 with the duty ratio DR2.

  When the switching pattern in the period A when the AC voltage Vac ≧ 0 is examined in detail, the switching elements Q1p, Q2n, Q4 are turned off, on, off mode 1, on, on, off mode 2, on, on, on There are three patterns of mode 3.

  In the mode 1, as shown in FIG. 3A, based on the energy stored in the reactors 14a and 14b, the diode D6, the reactor 14b, the switching element Q2n, the reactor 14a, and the diode D3 from the negative electrode of the DC load 20 are used. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged. At this time, although a reverse voltage is applied between the collector and the emitter of the switching element Q1n, the switching element Q1n can withstand because it is a reverse blocking IGBT.

  In mode 2, as shown in FIG. 3B, a current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the diode D6 and the reactor 14b. Further, a current flows from the positive electrode of the AC power source 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the diode D3, and the DC load 20 is charged. At this time, although a reverse voltage is applied between the collector and emitter of the switching element Q2n, the switching element Q2n can withstand because it is a reverse blocking IGBT.

  In mode 3, as shown in FIG. 3C, a current flows from the positive electrode of the AC power supply 10 to the negative electrode of the AC power supply 10 through the switching element Q1p, the reactor 14a, the transistor T4, the diode D6, and the reactor 14b. At this time, energy is stored in each of the reactors 14a and 14b.

  When AC voltage Vac ≧ 0, switching element Q1p operates as a switching element of the step-down circuit, and switching element Q4 operates as a switching element of the step-up PFC circuit. Further, the diodes D3 and D6 operate as rectifier diodes.

  On the other hand, when the switching pattern in period B when AC voltage Vac <0 is examined in detail, switching elements Q1n, Q2p, and Q6 are turned off, on, off mode 4, on, on, off mode 5, on, on , There are three patterns of on mode 6.

  In the mode 4, as shown in FIG. 4A, based on the energy stored in the reactors 14a and 14b, the diode D4, the reactor 14a, the switching element Q2p, the reactor 14b, and the diode D5 from the negative electrode of the DC load 20 are used. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged. At this time, although a reverse voltage is applied between the collector and the emitter of the switching element Q1p, the switching element Q1p can withstand because it is a reverse blocking IGBT.

  In mode 5, as shown in FIG. 4B, a current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power supply 10 through the diode D4, the reactor 14a, and the switching element Q1n. Further, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the diode D5, and the DC load 20 is charged. At this time, although a reverse voltage is applied between the collector and emitter of the switching element QQ2p, the switching element Q2p can withstand because it is a reverse blocking IGBT.

  In mode 6, as shown in FIG. 4C, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the AC power supply 10 through the reactor 14b, the transistor T6, the diode D4, the reactor 14a, and the switching element Q1n. At this time, energy is stored in each of the reactors 14a and 14b.

  When AC voltage Vac <0, switching element Q1n operates as a switching element of the step-down circuit, and switching element Q6 operates as a switching element of the step-up PFC circuit. The diodes D4 and D5 operate as rectifier diodes.

  According to 1st Embodiment described above, there exist the following effects.

  • When converting AC power to DC power, the three elements conduct. Therefore, conduction loss can be suppressed. Therefore, it is possible to convert power from alternating current to direct current while achieving both improvement in power conversion efficiency and reduction in cost.

  When AC voltage Vac ≧ 0, step-down control can be performed by switching the switching element Q1p, and step-up control can be performed by switching the transistor T4. When AC voltage Vac <0, step-down control can be performed by switching switching element Q1n, and step-up control can be performed by switching transistor T6.

  By applying a value calculated based on DC voltage feedback control, which has reactor current control in the minor loop, to the duty ratio DR2, it is possible to always perform PFC control.

(Second Embodiment)
In the charging process according to the second embodiment, when the magnitude | Vac | (absolute value) of the AC voltage Vac is smaller than the DC voltage Vo, boost control is performed, and when | Vac | is larger than the DC voltage Vo. Implement step-down control. Hereinafter, the charging process according to the second embodiment will be described with reference to FIGS. FIG. 5 is a time chart corresponding to FIG. 6A and 6B are circuit diagrams showing the flow of current when the AC voltage Vac ≧ 0 and | Vac | <Vo, and FIGS. 6C and 6D show the AC voltage Vac ≧ 0. FIG. 6 is a circuit diagram showing a current flow when 0 and | Vac | ≧ Vo. FIGS. 7A and 7B are circuit diagrams showing a current flow when the AC voltage Vac <0 and | Vac | <Vo. FIGS. 7C and 7D show the AC voltage Vac <0. FIG. 6 is a circuit diagram showing a current flow when 0 and | Vac | ≧ Vo.

  As shown in FIG. 5, when the AC voltage Vac ≧ 0, the switching element Q2n is always turned on. Further, when | Vac | ≧ Vo, the switching element Q1p is switched at the duty ratio DR3 (third duty ratio). When | Vac | <Vo, the switching element Q1p is always turned on, and the switching element Q4 is turned on. Switching is performed at a duty ratio DR4 (fourth duty ratio).

  On the other hand, when AC voltage Vac <0, switching element Q2p is always turned on. Further, when | Vac | ≧ Vo, the switching element Q1n is switched with the duty ratio DR3. When | Vac | <Vo, the switching element Q1n is always turned on and the switching element Q6 is switched with the duty ratio DR4. . Note that the duty ratios DR3 and DR4 are values calculated based on DC voltage feedback control having reactor current control in a minor loop, similarly to the duty ratio DR2.

  When the switching pattern is examined in detail during period A when AC voltage Vac ≧ 0 and | Vac | <Vo, switching element Q1p, Q2n, Q4 is in on, on, off mode 1, on, on, on mode. There are two patterns.

  In the mode 1, as shown in FIG. 6A, current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the diode D6 and the reactor 14b based on the energy stored in the reactor 14b. Further, based on the energy stored in the reactor 14a, a current flows from the positive electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the diode D3, and the DC load 20 is charged.

  In mode 2, as shown in FIG. 6B, a current flows from the positive electrode of the AC power supply 10 to the negative electrode of the AC power supply 10 through the switching element Q1p, the reactor 14a, the transistor T4, the diode D6, and the reactor 14b. At this time, energy is stored in each of the reactors 14a and 14b.

  When the switching pattern is examined in detail in period B when AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching elements Q1p, Q2n, and Q4 are in OFF, ON, OFF mode 3, ON, ON, OFF mode. There are two patterns of four.

  In mode 3, as shown in FIG. 6C, based on the energy stored in the reactors 14a and 14b, the diode D6, the reactor 14b, the switching element Q2n, the reactor 14a, and the diode D3 from the negative electrode of the DC load 20 are used. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In mode 4, as shown in FIG. 6D, a current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the diode D6 and the reactor 14b. At this time, energy is stored in the reactor 14b. Further, a current flows from the positive electrode of the AC power source 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the diode D3. At this time, energy is stored in the reactor 14a and the DC load 20 is charged.

  When AC voltage Vac ≧ 0 and | Vac | <Vo, switching element Q4 operates as a switching element of the boost PFC circuit, and when AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching element Q1p is step-down PFC. Operates as a switching element of the circuit. When AC voltage Vac ≧ 0, diodes D3 and D6 operate as rectifier diodes.

  Further, in the period C when the AC voltage Va <0 and | Vac | <Vo, when the switching pattern is examined in detail, the switching elements Q1n, Q2p, Q6 are in the on, on, off mode 5, on, on, on There are two patterns of mode 6.

  In mode 5, as shown in FIG. 7 (a), current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power source 10 through the diode D4, the reactor 14a, and the switching element Q1n based on the energy stored in the reactor 14a. Flows. Further, based on the energy stored in the reactor 14b, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the diode D5, and the DC load 20 is charged.

  In mode 6, as shown in FIG. 7B, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the AC power supply 10 through the reactor 14b, the transistor T6, the diode D4, the reactor 14a, and the switching element Q1n. At this time, energy is stored in each of the reactors 14a and 14b.

  In the period D when the AC voltage Va <0 and | Vac | ≧ Vo, the switching pattern Q1n, Q2p, Q6 is in the off, on, off mode 7, on, on, on mode. There are two patterns of eight.

  In the mode 7, as shown in FIG. 7C, based on the energy stored in the reactors 14a and 14b, the diode D4, the reactor 14a, the switching element Q2p, the reactor 14b, and the diode D5 from the negative electrode of the DC load 20 are used. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In mode 8, as shown in FIG. 7D, a current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power supply 10 through the diode D4, the reactor 14a, and the switching element Q1n. At this time, energy is stored in the reactor 14a. Further, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the diode D5. At this time, energy is stored in the reactor 14b and the DC load 20 is charged.

  When AC voltage Vac <0 and | Vac | <Vo, switching element Q6 operates as a switching element of the boost PFC circuit, and when AC voltage Vac <0 and | Vac | ≧ Vo, switching element Q1n is step-down PFC. Operates as a switching element of the circuit. When AC voltage Vac <0, diodes D4 and D5 operate as rectifier diodes.

  According to 2nd Embodiment described above, there exist the following effects.

  • When converting AC power to DC power, the three elements conduct. Therefore, conduction loss can be suppressed. Therefore, it is possible to convert power from alternating current to direct current while achieving both improvement in power conversion efficiency and reduction in cost.

  When AC voltage Vac ≧ 0 and | Vac | <Vo, step-up control can be performed by switching the transistor T4. When AC voltage Vac ≧ 0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1p. When the AC voltage Vac <0 and | Vac | <Vo, step-up control can be performed by switching the transistor T6. When AC voltage Vac <0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1n.

  By applying a value calculated based on the DC voltage feedback control having the reactor current control in the minor loop to the duty ratios DR3 and DR4, the PFC control can always be performed.

(Third embodiment)
In the charging process according to the third embodiment, when the magnitude | Vac | of the AC voltage Vac is smaller than the DC voltage Vo, the step-down control is stopped and the step-up control is always performed. Hereinafter, the charging process according to the third embodiment will be described with reference to FIGS. FIG. 8 is a time chart corresponding to FIG. FIGS. 9A to 9C are circuit diagrams showing the flow of current when the AC voltage Vac ≧ 0. FIGS. 10A to 10C are circuit diagrams illustrating the flow of current when the AC voltage Vac <0.

  As shown in FIG. 8, when the AC voltage Vac ≧ 0, the switching element Q2n is always turned on. Further, when | Vac | ≧ Vo, switching element Q1p is switched at duty ratio DR5 (fifth duty ratio), and switching element Q4 is switched at duty ratio DR6 (sixth duty ratio). When | Vac | <Vo, switching element Q1p is always turned on, and switching element Q4 is switched at duty ratio DR6.

  On the other hand, when AC voltage Vac <0, switching element Q2p is always turned on. Further, when | Vac | ≧ Vo, switching element Q1n is switched at duty ratio DR5, and switching element Q6 is switched at duty ratio DR6. When | Vac | <Vo, switching element Q1n is always turned on, and switching element Q6 is switched at duty ratio DR6.

  The duty ratio DR5 is set to 1− (k × Vo) / | Vac | when | Vac | ≧ k × Vo (0.9 ≦ k ≦ 1.0), and | Vac | <k × Vo Is set to 1.0 (100%). Similarly to the duty ratio DR2, the duty ratio DR6 is a value calculated based on DC voltage feedback control having reactor current control in a minor loop.

  When the switching pattern is examined in detail during period A when AC voltage Vac ≧ 0 and | Vac | <Vo, switching element Q1p, Q2n, Q4 is in on, on, off mode 1, on, on, on mode. There are two patterns.

  In mode 1, as shown in FIG. 9A, a current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the diode D6 and the reactor 14b. Further, a current flows from the positive electrode of the AC power source 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the diode D3, and the DC load 20 is charged.

  In mode 2, as shown in FIG. 9B, a current flows from the positive electrode of the AC power supply 10 to the negative electrode of the AC power supply 10 through the switching element Q1p, the reactor 14a, the transistor T4, the diode D6, and the reactor 14b. At this time, energy is stored in each of the reactors 14a and 14b.

  When the switching pattern is examined in detail in period B when AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching elements Q1p, Q2n, and Q4 are in OFF, ON, OFF mode 3, ON, ON, OFF mode. There are three patterns: 1, ON, ON, and ON mode 2. Mode 1 and mode 2 have the same pattern as mode 1 and mode 2 in period A.

  In mode 3, as shown in FIG. 9C, the diode D6, the reactor 14b, the switching element Q2n, the reactor 14a, and the diode D3 are connected to the negative electrode of the DC load 20 based on the energy stored in the reactors 14a and 14b. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  When AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching element Q1p operates as a switching element of the step-down circuit. When AC voltage Vac ≧ 0, switching element Q4 operates as a switching element of the boost PFC circuit, and diodes D3 and D6 operate as rectifier diodes.

  Further, in the period C when the AC voltage Va <0 and | Vac | <Vo, the switching pattern Q1n, Q2p, Q6 is on, on, off mode 4, on, on, on. There are two patterns of mode 5.

  In mode 4, as shown in FIG. 10A, a current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power supply 10 through the diode D4, the reactor 14a, and the switching element Q1n. Further, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the diode D5, and the DC load 20 is charged.

  In mode 5, as shown in FIG. 10B, current flows from the negative electrode of the AC power supply 10 to the positive electrode of the AC power supply 10 through the reactor 14b, the transistor T6, the diode D4, the reactor 14a, and the switching element Q1n. At this time, energy is stored in each of the reactors 14a and 14b.

  In the period D when the AC voltage Va <0 and | Vac | ≧ Vo, the switching pattern Q1n, Q2p, Q6 is turned off, on, off mode 6, on, on, off mode. There are three patterns of 4, ON, ON, ON mode 5. Mode 4 and mode 5 have the same pattern as mode 4 and mode 5 in period C.

  In mode 6, as shown in FIG. 10C, the diode D4, the reactor 14a, the switching element Q2p, the reactor 14b, and the diode D5 are connected to the negative electrode of the DC load 20 based on the energy stored in the reactors 14a and 14b. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  When AC voltage Vac <0 and | Vac | ≧ Vo, switching element Q1n operates as a switching element of the step-down circuit. When AC voltage Vac <0, switching element Q6 operates as a switching element of the boost PFC circuit, and diodes D4 and D5 operate as rectifier diodes.

  According to 3rd Embodiment described above, there exist the following effects.

  • When converting AC power to DC power, the three elements conduct. Therefore, conduction loss can be suppressed. Therefore, it is possible to convert power from alternating current to direct current while achieving both improvement in power conversion efficiency and reduction in cost.

  When AC voltage Vac ≧ 0, step-up control can be performed by switching transistor T4. When AC voltage Vac ≧ 0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1p. When AC voltage Vac <0, step-up control can be performed by switching transistor T6. When AC voltage Vac <0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1n.

  By applying a value calculated based on DC voltage feedback control having reactor current control in the minor loop to the duty ratio DR6, PFC control can always be performed.

(Fourth embodiment)
In the fourth to sixth embodiments, discharge processing (reverse power flow control) for converting AC power into DC power is performed. As shown in FIG. 11, an AC load 50 is connected to the AC side connection terminals 11a and 11b of the power conversion devices 40 according to the fourth to sixth embodiments, and a DC power source 60 is connected to the DC side connection terminals 21a and 21b. Is connected. The control device 30 performs a discharge process of converting the DC power of the DC power source 60 into AC power and supplying the AC power 50. Hereinafter, the discharge process will be described in detail with reference to FIGS. FIG. 12A is a time chart showing changes in the DC voltage Vo and the output voltage Vac supplied to the AC load 50. FIGS. 12B to 12I are time charts showing on / off timings of the switching elements Q1p, Q1n, Q2p, Q2n, Q3, Q4, Q5, and Q6. FIGS. 13A to 13C are circuit diagrams showing the flow of current when the AC voltage Vac ≧ 0, and FIGS. 14A to 14C show the current flow when the AC voltage Vac <0. It is a circuit diagram which shows a flow.

  As shown in FIG. 12, when AC voltage Vac ≧ 0, switching elements Q1n and Q6 are always turned on. Further, the switching element Q2p is switched at the duty ratio DR7 (seventh duty ratio), and the switching element Q3 is switched at the duty ratio DR8 (eighth duty ratio). On the other hand, when AC voltage Vac <0, switching elements Q1p and Q4 are always turned on. Further, the switching element Q2n is switched at the duty ratio DR7, and the switching element Q5 is switched at the duty ratio DR8.

  The duty ratio DR7 is set to kVo / | Vac * | (0.9 ≦ k ≦ 1.0) where the target AC voltage is Vac *. The duty ratio DR8 is a value calculated based on feedback control of AC voltage having reactor current control in the minor loop. Specifically, the target reactor current is set so that the voltage deviation between the target AC voltage and the AC voltage detected by the voltage sensor 17 approaches zero. Further, the duty ratio DR8 is calculated so that the reactor current is subjected to feedback control and feedforward control. The calculated duty ratio DR8 increases as | Vac | increases. PFC control can be realized by switching the switching elements Q3 and Q5 with the duty ratio DR8.

  Looking at the switching pattern in period A when AC voltage Vac ≧ 0 in detail, switching element Q1n, Q2p, Q3, Q6 is on, on, on, on mode 1, on, off, on, on mode 2. There are three patterns of mode 3, ON, OFF, OFF, ON.

  In mode 1, as shown in FIG. 13A, current flows from the positive electrode of the DC power supply 60 to the negative electrode of the DC power supply 60 through the transistor T3, the reactor 14a, the switching element Q2p, the reactor 14b, and the transistor T6. At this time, energy is stored in each of the reactors 14a and 14b.

  In mode 2, as shown in FIG. 13B, a current flows from the positive electrode of the DC power supply 60 to the positive electrode of the AC load 50 through the transistor T3, the reactor 14a, and the switching element Q1n. Further, a current flows from the negative electrode of the AC load 50 to the negative electrode of the DC power source 60 through the reactor 14b and the transistor T6.

  In the mode 3, as shown in FIG. 13C, based on the energy stored in the reactors 14a and 14b, the reactor 14b, the transistor T6, the diode D4, the reactor 14a, and the switching element Q1n are switched from the negative electrode of the AC load 50. A current flows to the positive electrode of the AC load 50 through.

  When AC voltage Vac ≧ 0, switching element Q3 operates as a switching element of the step-down circuit, and switching element Q2p operates as a switching element of the step-up circuit.

  On the other hand, when the switching pattern in period B when AC voltage Vac <0 is examined in detail, switching elements Q1p, Q2n, Q5, and Q4 are on, on, on, on mode 4, on, off, on, on. There are three patterns: mode 5, mode 6, on, off, off, on.

  In mode 4, as shown in FIG. 14A, current flows from the positive electrode of the DC power supply 60 to the negative electrode of the DC power supply 60 through the transistor T5, the reactor 14b, the switching element Q2n, the reactor 14a, and the transistor T4. At this time, energy is stored in each of the reactors 14a and 14b.

  In mode 5, as shown in FIG. 14B, a current flows from the positive electrode of the DC power supply 60 to the negative electrode of the AC load 50 through the transistor T5 and the reactor 14b. Further, a current flows from the positive electrode of the AC load 50 to the negative electrode of the DC power source 60 through the switching element Q1p, the reactor 14a, and the transistor T4.

  In mode 6, as shown in FIG. 14C, based on the energy stored in the reactors 14a and 14b, the switching element Q1p, the reactor 14a, the transistor T4, the diode D6, and the reactor 14b are connected from the positive electrode of the AC load 50. The current flows to the negative electrode of the AC load 50 through.

  When AC voltage Vac <0, switching element Q5 operates as a switching element of the step-down circuit, and switching element Q2n operates as a switching element of the step-up circuit.

  According to 4th Embodiment described above, there exist the following effects.

  • When converting DC power to AC power, the three elements conduct. Therefore, conduction loss can be suppressed. Therefore, it is possible to convert power from direct current to alternating current while achieving both improvement in power conversion efficiency and reduction in cost.

  When AC voltage Vac ≧ 0, step-down control can be performed by switching transistor T3, and step-up control can be performed by switching switching element Q2p. When AC voltage Vac <0, step-down control can be performed by switching transistor T5, and step-up control can be performed by switching switching element Q2n.

  -By applying the value calculated based on the feedback control of the AC voltage having the reactor current control in the minor loop to the duty ratio DR8, the PFC control can always be performed.

(Fifth embodiment)
In the charging process according to the fifth embodiment, when the magnitude of the DC voltage Vo is smaller than the magnitude | Vac | of the AC voltage Vac, boost control is performed, and the magnitude of the DC voltage Vo is larger than | Vac |. In this case, step-down control is performed. Hereinafter, the discharge process concerning 5th Embodiment is demonstrated with reference to FIGS. FIG. 15 is a time chart corresponding to FIG. FIGS. 16A and 16B are circuit diagrams showing the flow of current when the AC voltage Vac ≧ 0 and | Vac | <Vo, and FIGS. 16C and 16D show the AC voltage Vac ≧ 0. FIG. 6 is a circuit diagram showing a current flow when 0 and | Vac | ≧ Vo. FIGS. 17A and 17B are circuit diagrams showing the flow of current when the AC voltage Vac <0 and | Vac | <Vo. FIGS. 17C and 17D show the AC voltage Vac <0. FIG. 6 is a circuit diagram showing a current flow when 0 and | Vac | ≧ Vo.

  As shown in FIG. 15, when AC voltage Vac ≧ 0, switching elements Q1n and Q6 are always turned on. Further, when | Vac | ≧ Vo, switching element Q2p is switched at duty ratio DR9 (9th duty ratio), and switching element Q3 is always turned on. When | Vac | <Vo, the switching element Q3 is switched at the duty ratio DR10 (10th duty ratio).

  On the other hand, when AC voltage Vac <0, switching elements Q1p and Q4 are always turned on. Further, when | Vac | ≧ Vo, switching element Q2n is switched at duty ratio DR9, and switching element Q5 is always turned on. When | Vac | <Vo, switching element Q5 is switched at duty ratio DR10. The duty ratios DR9 and DR10 are values calculated based on the feedback control of the AC voltage having the reactor current control in the minor loop, similarly to the duty ratio DR8.

  In the period A when the AC voltage Vac ≧ 0 and | Vac | <Vo, the switching pattern Q1n, Q2p, Q3, Q6 is turned on, off, on, on mode 1, on, off. , Off, on mode 2 patterns.

  In mode 1, as shown in FIG. 16A, current flows from the positive electrode of the DC power supply 60 to the positive electrode of the AC load 50 through the transistor T3, the reactor 14a, and the switching element Q1n. At this time, energy is stored in the reactor 14a. Further, a current flows from the negative electrode of the AC load 50 to the negative electrode of the DC power source 60 through the reactor 14b and the transistor T6. At this time, energy is stored in the reactor 14b.

  In the mode 2, as shown in FIG. 16B, based on the energy stored in the reactors 14a and 14b, the reactor 14b, the transistor T6, the diode D4, the reactor 14a, and the switching element Q1n are switched from the negative electrode of the AC load 50. A current flows to the positive electrode of the AC load 50 through.

  In the period B when the AC voltage Vac ≧ 0 and | Vac | ≧ Vo, the switching pattern Q1n, Q2p, Q3, Q6 is turned on, on, on, on mode 3, on, off. , ON, ON mode 4 patterns.

  In mode 3, as shown in FIG. 16C, a current flows from the positive electrode of the DC power supply 60 to the negative electrode of the DC power supply 60 through the transistor T3, the reactor 14a, the switching element Q2p, the reactor 14b, and the transistor T6. At this time, energy is stored in each of the reactors 14a and 14b.

  In mode 4, as shown in FIG. 16D, based on the energy stored in the reactor 14a, current flows from the positive electrode of the DC power supply 60 to the positive electrode of the AC load 50 through the transistor T3, the reactor 14a, and the switching element Q1n. Flows. Further, based on the energy stored in the reactor 14b, a current flows from the negative electrode of the AC load 50 to the negative electrode of the DC power supply 60 through the reactor 14b and the transistor T6.

  When AC voltage Vac ≧ 0 and | Vac | <Vo, switching element Q3 operates as a switching element of the step-down circuit. When AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching element Q2p is a boost PFC circuit. It operates as a switching element.

  Further, in the period C when the AC voltage Va <0 and | Vac | <Vo, the switching patterns Q1p, Q2n, Q5, and Q4 are turned on, off, on, on mode 5 and on. , Off, off, on mode 2 patterns.

  In mode 5, as shown in FIG. 17A, current flows from the positive electrode of the DC power supply 60 to the negative electrode of the AC load 50 through the transistor T5 and the reactor 14b. At this time, energy is stored in the reactor 14b. Further, a current flows from the positive electrode of the AC load 50 to the negative electrode of the DC power source 60 through the switching element Q1p, the reactor 14a, and the transistor T4. At this time, energy is stored in the reactor 14a.

  In the mode 6, as shown in FIG. 17B, based on the energy stored in the reactors 14a and 14b, the switching element Q1p, the reactor 14a, the transistor T4, the diode D6, and the reactor 14b are connected from the positive electrode of the AC load 50. The current flows to the negative electrode of the AC load 50 through.

  In the period D when the AC voltage Va <0 and | Vac | ≧ Vo, the switching pattern Q1p, Q2n, Q5, Q4 is turned on, on, on, on mode 7, on, off. There are two patterns of mode 8 of ON, ON.

  In mode 7, as shown in FIG. 17C, a current flows from the positive electrode of the DC power supply 60 to the negative electrode of the DC power supply 60 through the transistor T5, the reactor 14b, the switching element Q2n, the reactor 14a, and the transistor T4. At this time, energy is stored in each of the reactors 14a and 14b.

  In mode 8, as shown in FIG. 17D, current flows from the positive electrode of the DC power supply 60 to the negative electrode of the AC load 50 through the transistor T5 and the reactor 14b based on the energy stored in the reactor 14b. Further, based on the energy stored in the reactor 14a, a current flows from the positive electrode of the AC load 50 to the negative electrode of the DC power supply 60 through the switching element Q1p, the reactor 14a, and the transistor T4.

  When AC voltage Vac <0 and | Vac | <Vo, switching element Q5 operates as a switching element of the step-down circuit, and when AC voltage Vac <0 and | Vac | ≧ Vo, switching element Q2n is a boost PFC circuit. It operates as a switching element.

  According to 5th Embodiment described above, there exist the following effects.

  • When converting DC power to AC power, the three elements conduct. Therefore, conduction loss can be suppressed. Therefore, it is possible to convert power from direct current to alternating current while achieving both improvement in power conversion efficiency and reduction in cost.

  When the AC voltage Vac ≧ 0 and | Vac | <Vo, the step-down control can be performed by switching the transistor T3. When the AC voltage Vac ≧ 0 and | Vac | ≧ Vo, the boost control can be performed by switching the switching element Q2p. When the AC voltage Vac <0 and | Vac | <Vo, step-down control can be performed by switching the transistor T5. When AC voltage Vac <0 and | Vac | ≧ Vo, step-up control can be performed by switching switching element Q2n.

  By applying a value calculated based on the feedback control of the AC voltage having the reactor current control in the minor loop to the duty ratios DR9 and DR10, the PFC control can always be performed.

(Sixth embodiment)
In the discharge processing according to the sixth embodiment, when the magnitude of the DC voltage Vo is larger than the magnitude | Vac | of the AC voltage Vac, the boost control is stopped and the buck control is always performed. Hereinafter, the discharge process concerning 6th Embodiment is demonstrated with reference to FIGS. FIG. 18 is a time chart corresponding to FIG. FIGS. 19A to 19C are circuit diagrams illustrating the flow of current when the AC voltage Vac ≧ 0. 20A to 20C are circuit diagrams showing the flow of current when the AC voltage Vac <0.

  As shown in FIG. 18, when AC voltage Vac ≧ 0, switching elements Q1n and Q6 are always turned on. Further, when | Vac | ≧ Vo, the switching element Q2p is switched at the duty ratio DR11 (11th duty ratio), and the switching element Q3 is switched at the duty ratio DR12 (12th duty ratio). When | Vac | <Vo, switching element Q3 is switched at duty ratio DR12.

  On the other hand, when AC voltage Vac <0, switching elements Q1p and Q4 are always turned on. Further, when | Vac | ≧ Vo, switching element Q2n is switched at duty ratio DR11 and switching element Q5 is switched at duty ratio DR12. When | Vac | <Vo, switching element Q5 is switched at duty ratio DR12.

  The duty ratio DR11 is set to 1− (k × Vo) / | Vac * | when | Vac * | ≧ k × Vo (0.9 ≦ k ≦ 1.0), and | Vac * | <k When xVo, 1.0 (100%) is set. Similarly to the duty ratio DR8, the duty ratio DR12 is a value calculated based on AC voltage feedback control having reactor current control in a minor loop.

  In the period A when the AC voltage Vac ≧ 0 and | Vac | <Vo, the switching pattern Q1n, Q2p, Q3, Q6 is turned on, off, on, on mode 1, on, off. , Off, on mode 2 patterns.

  In mode 1, as shown in FIG. 19A, a current flows from the positive electrode of the DC power supply 60 to the positive electrode of the AC load 50 through the transistor T3, the reactor 14a, and the switching element Q1n. Further, a current flows from the negative electrode of the AC load 50 to the negative electrode of the DC power source 60 through the reactor 14b and the transistor T6.

  In the mode 2, as shown in FIG. 19B, based on the energy stored in the reactors 14a and 14b, the reactor 14b, the transistor T6, the diode D4, the reactor 14a, and the switching element Q1n are switched from the negative electrode of the AC load 50. A current flows to the positive electrode of the AC load 50 through.

  In the period B when the AC voltage Vac ≧ 0 and | Vac | ≧ Vo, the switching pattern Q1n, Q2p, Q3, Q6 is turned on, on, on, on mode 3, on, off. , On, on mode 1 and on, off, off, on mode 2. Mode 1 and mode 2 are the same as mode 1 and mode 2 of period A.

  In mode 3, as shown in FIG. 19C, a current flows from the positive electrode of the DC power supply 60 to the negative electrode of the DC power supply 60 through the transistor T3, the reactor 14a, the switching element Q2p, the reactor 14b, and the transistor T6. At this time, energy is stored in each of the reactors 14a and 14b.

  When AC voltage Vac ≧ 0, switching element Q3 operates as a switching element of the step-down circuit, and when AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching element Q2p operates as a switching element of the boosting circuit.

  Further, in the period C when the AC voltage Va <0 and | Vac | <Vo, when the switching pattern is examined in detail, the switching elements Q1p, Q2n, Q5, Q4 are turned on, off, on, on mode 4, on , OFF, OFF, ON mode 5 patterns.

  In mode 4, as shown in FIG. 20A, a current flows from the positive electrode of the DC power supply 60 to the negative electrode of the AC load 50 through the transistor T5 and the reactor 14b. Further, a current flows from the positive electrode of the AC load 50 to the negative electrode of the DC power source 60 through the switching element Q1p, the reactor 14a, and the transistor T4.

  In the mode 5, as shown in FIG. 20B, based on the energy stored in the reactors 14a and 14b, the switching element Q1p, the reactor 14a, the transistor T4, the diode D6, and the reactor 14b are connected from the positive electrode of the AC load 50. The current flows to the negative electrode of the AC load 50 through.

  In the period D when the AC voltage Va <0 and | Vac | ≧ Vo, the switching pattern Q1p, Q2n, Q5, Q4 is in the on, on, on, on mode 6, on, off. , On, on mode 4 and on, off, off, on mode 5. Mode 4 and mode 5 are the same as mode 4 and mode 5 in period C.

  In mode 6, as shown in FIG. 20C, a current flows from the positive electrode of the DC power supply 60 to the negative electrode of the DC power supply 60 through the transistor T5, the reactor 14b, the switching element Q2n, the reactor 14a, and the transistor T4. At this time, energy is stored in each of the reactors 14a and 14b.

  When AC voltage Vac <0, switching element Q5 operates as a switching element of the step-down circuit, and when AC voltage Vac <0 and | Vac | ≧ Vo, switching element Q2n operates as a switching element of the booster circuit.

  According to the sixth embodiment described above, the following effects are obtained.

  • When converting DC power to AC power, the three elements conduct. Therefore, conduction loss can be suppressed. Therefore, it is possible to convert power from direct current to alternating current while achieving both improvement in power conversion efficiency and reduction in cost.

  When the AC voltage Vac ≧ 0, the step-down control can be performed by switching the transistor T3. When the AC voltage Vac ≧ 0 and | Vac | ≧ Vo, the boost control can be performed by switching the switching element Q2p. When AC voltage Vac <0, step-down control can be performed by switching transistor T5. When AC voltage Vac <0 and | Vac | ≧ Vo, step-up control can be performed by switching switching element Q2n.

  -By applying the value calculated based on the feedback control of the AC voltage having the reactor current control in the minor loop to the duty ratio DR12, the PFC control can always be performed.

(Seventh embodiment)
In the seventh embodiment, in the charging process, synchronous rectification is performed by the switching elements Q3 and Q6 when the AC voltage Vac ≧ 0, and synchronous rectification is performed by the switching elements Q4 and Q5 when the AC voltage Vac <0. Hereinafter, the seventh embodiment will be described with respect to differences from the first embodiment with reference to FIGS. FIG. 21 is a time chart corresponding to FIG. 22A to 22C are circuit diagrams corresponding to FIGS. 3A to 3C. FIGS. 23A to 23C are circuit diagrams corresponding to FIGS. 4A to 4C.

  When the AC voltage Vac ≧ 0, as shown in FIGS. 22A to 22C, when the diodes D3 and D6 are turned on in FIGS. 3A to 3C, the transistors T3 and T6 are turned on, respectively. To. In general, the conduction losses of the transistors T3 and T6 are smaller than the conduction losses of the diodes D3 and D6.

  When the AC voltage Vac <0, as shown in FIGS. 23A to 23C, the transistors T4 and T5 are turned on when the diodes D4 and D5 are turned on in FIGS. Turn on each one. In general, the conduction losses of the transistors T4 and T5 are smaller than the conduction losses of the diodes D4 and D5. Therefore, according to the seventh embodiment, the conduction loss can be further suppressed as compared with the first embodiment.

(Eighth embodiment)
Similarly to the seventh embodiment, in the charging process, the eighth embodiment performs synchronous rectification by the switching elements Q3 and Q6 when the alternating voltage Vac ≧ 0, and the switching element Q4 when the alternating voltage Vac <0. , Q5 performs synchronous rectification. Hereinafter, the eighth embodiment will be described with respect to differences from the second embodiment with reference to FIGS. FIG. 24 is a time chart corresponding to FIG. 25 (a) to 25 (d) are circuit diagrams corresponding to FIGS. 6 (a) to 6 (d). 26 (a) to (d) are circuit diagrams corresponding to FIGS. 7 (a) to (d).

  When AC voltage Vac ≧ 0, as shown in FIGS. 25A to 25D, when diodes D3 and D6 are turned on in FIGS. 6A to 6D, transistors T3 and T6 are turned on, respectively. To. When the AC voltage Vac <0, as shown in FIGS. 26A to 26D, the transistors T4 and T5 are turned on when the diodes D4 and D5 are turned on in FIGS. Turn on each one. Therefore, according to the eighth embodiment, the conduction loss can be further suppressed than in the second embodiment.

(Ninth embodiment)
Similarly to the seventh embodiment, in the charging process, the ninth embodiment performs synchronous rectification by the switching elements Q3 and Q6 when the AC voltage Vac ≧ 0, and the switching element Q4 when the AC voltage Vac <0. , Q5 performs synchronous rectification. Hereinafter, the ninth embodiment will be described with respect to differences from the third embodiment with reference to FIGS. FIG. 27 is a time chart corresponding to FIG. FIGS. 28A to 28C are circuit diagrams corresponding to FIGS. 9A to 9C. 29A to 29C are circuit diagrams corresponding to FIGS. 10A to 10C.

  When AC voltage Vac ≧ 0, as shown in FIGS. 28A to 28C, when diodes D3 and D6 are turned on in FIGS. 9A to 9C, transistors T3 and T6 are turned on, respectively. To. When the AC voltage Vac <0, as shown in FIGS. 29A to 29C, when the diodes D4 and D5 are turned on in FIGS. 10A to 10C, the transistors T4 and T5 are turned on. Turn on each one. Therefore, according to the ninth embodiment, the conduction loss can be further suppressed as compared with the third embodiment.

(10th Embodiment)
In the tenth embodiment, a charging process is performed. Hereinafter, differences from the first embodiment will be described with reference to FIGS. FIG. 30 is a time chart corresponding to FIG. 31 (a) to 31 (c) are circuit diagrams corresponding to FIGS. 3 (a) to 3 (c). 32 (a) to 32 (c) are circuit diagrams corresponding to FIGS. 4 (a) to 4 (c). In this embodiment, when the AC voltage Vac ≧ 0, the transistors T3 and T6 perform rectification, and when the AC voltage Vac <0, the transistors T4 and T5 perform rectification. Further, when the alternating voltage Vac <0, the switching element Q6 is switched in the first embodiment, but the switching element Q3 is switched in the present embodiment.

  As shown in FIG. 30, the switching patterns of the switching elements Q1p, Q1n, Q2p, Q2n are the same as in the first embodiment. When AC voltage Vac ≧ 0, switching elements Q2n and Q6 are always turned on. Further, the switching element Q4 is switched at the duty ratio DR2, and the switching element Q3 is inverted and switched with respect to the switching element Q4. That is, the switching element Q3 is turned off when the switching element Q4 is on, and the switching element Q3 is turned on when the switching element Q4 is off. On the other hand, when AC voltage Vac <0, switching elements Q2p and Q5 are always turned on. Further, the switching element Q3 is switched at the duty ratio DR2, and the switching element Q4 is inverted and switched with respect to the switching element Q3.

  When the switching pattern in the period A when the AC voltage Vac ≧ 0 is examined in detail, the switching elements Q1p, Q2n, Q3, Q4 are off, on, on, off mode 1, on, on, on, off mode 2. There are 3 patterns of mode 3, ON, ON, OFF, ON.

  In the mode 1, as shown in FIG. 31 (a), based on the energy stored in the reactors 14a and 14b, the transistor T6, the reactor 14b, the switching element Q2n, the reactor 14a, the transistor T3 from the negative electrode of the DC load 20 are used. The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In mode 2, as shown in FIG. 31B, current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the transistor T6 and the reactor 14b. In addition, a current flows from the positive electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the transistor T3, and the DC load 20 is charged.

  In mode 3, as shown in FIG. 31 (c), current flows from the positive electrode of the AC power supply 10 to the negative electrode of the AC power supply 10 through the switching element Q1p, the reactor 14a, the transistor T4, the transistor T6, and the reactor 14b. At this time, energy is stored in each of the reactors 14a and 14b.

  On the other hand, when the switching pattern in the period B when the AC voltage Vac <0 is examined in detail, the switching elements Q1n, Q2p, Q3, Q4 are turned on, on, off, on mode 4, on, on, off, on There are three patterns: mode 5, mode 6, on, on, on, off.

  In mode 4, as shown in FIG. 32A, based on the energy stored in the reactors 14a and 14b, from the negative electrode of the DC load 20, the transistor T4, the reactor 14a, the switching element Q2p, the reactor 14b, and the transistor T5 The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In mode 5, as shown in FIG. 32 (b), a current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power supply 10 through the transistor T4, the reactor 14a, and the switching element Q1n. Further, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the transistor T5, and the DC load 20 is charged.

  In mode 6, as shown in FIG. 32 (c), a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the AC power supply 10 through the reactor 14b, the transistor T5, the transistor T3, the reactor 14a, and the switching element Q1n. At this time, energy is stored in each of the reactors 14a and 14b.

  Therefore, according to the tenth embodiment, when the AC voltage Vac ≧ 0, step-down control can be performed by switching the switching element Q1p, and step-up control can be performed by switching the transistor T4. When AC voltage Vac <0, step-down control can be performed by switching switching element Q1n, and step-up control can be performed by switching transistor T3.

(Eleventh embodiment)
In the eleventh embodiment, a charging process is performed. Hereinafter, with reference to FIGS. 33 to 35, differences from the second embodiment will be described. FIG. 33 is a time chart corresponding to FIG. 34 (a) to (d) are circuit diagrams corresponding to FIGS. 6 (a) to (d). 35 (a) to 35 (d) are circuit diagrams corresponding to FIGS. 7 (a) to 7 (d). In this embodiment, when the AC voltage Vac ≧ 0, the transistors T3 and T6 perform rectification, and when the AC voltage Vac <0, the transistors T4 and T5 perform rectification. Further, when the AC voltage Va <0 and | Vac | <Vo, the switching element Q6 is switched in the second embodiment, but the switching element Q3 is switched in the present embodiment.

  As shown in FIG. 33, the switching patterns of the switching elements Q1p, Q1n, Q2p, Q2n are the same as those in the second embodiment. When AC voltage Vac ≧ 0, switching elements Q2n and Q6 are always turned on. Further, when | Vac | ≧ Vo, switching element Q1p is switched at duty ratio DR3, and switching element Q3 is always turned on. When | Vac | <Vo, the switching element Q1p is always turned on, the switching element Q4 is switched with the duty ratio DR4, and the switching element Q3 is inverted with respect to the switching element Q4.

  On the other hand, when AC voltage Vac <0, switching elements Q2p and Q5 are always turned on. Further, when | Vac | ≧ Vo, the switching element Q1n is switched at the duty ratio DR3, and the switching element Q4 is always turned on. When | Vac | <Vo, the switching element Q1n is always turned on, the switching element Q3 is switched at the duty ratio DR4, and the switching element Q4 is inverted and switched with respect to the switching element Q3.

  When the switching pattern is examined in detail during period A when AC voltage Vac ≧ 0 and | Vac | <Vo, switching elements Q1p, Q2n, Q3, and Q4 are in ON, ON, ON, OFF mode 1, ON, ON. , Off, on mode 2 patterns.

  In mode 1, as shown in FIG. 34A, current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the transistor T6 and the reactor 14b based on the energy stored in the reactor 14b. Further, based on the energy stored in the reactor 14a, a current flows from the positive electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the transistor T3, and the DC load 20 is charged.

  In mode 2, as shown in FIG. 34B, a current flows from the positive electrode of the AC power supply 10 to the negative electrode of the AC power supply 10 through the switching element Q1p, the reactor 14a, the transistor T4, the transistor T6, and the reactor 14b. At this time, energy is stored in each of the reactors 14a and 14b.

  When the switching pattern is examined in detail during period B when AC voltage Vac ≧ 0 and | Vac | ≧ Vo, switching elements Q1p, Q2n, Q3, and Q4 are in OFF, ON, ON, OFF mode 3, ON, ON. There are two patterns of mode 4 of ON, OFF.

  In mode 3, as shown in FIG. 34 (c), based on the energy stored in the reactors 14a and 14b, from the negative electrode of the DC load 20, the transistor T6, the reactor 14b, the switching element Q2n, the reactor 14a, the transistor T3 The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In mode 4, as shown in FIG. 34 (d), current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the transistor T6 and the reactor 14b. At this time, energy is stored in the reactor 14b. Further, a current flows from the positive electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the transistor T3. At this time, energy is stored in the reactor 14a and the DC load 20 is charged.

  Further, in the period C when the AC voltage Va <0 and | Vac | <Vo, when the switching pattern is examined in detail, the switching elements Q1n, Q2p, Q3, Q4 are turned on, on, off, on mode 5, on , On, on, off mode 6 patterns.

  In mode 5, as shown in FIG. 35 (a), current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power source 10 through the transistor T4, the reactor 14a, and the switching element Q1n based on the energy stored in the reactor 14a. Flows. Further, based on the energy stored in the reactor 14b, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the transistor T5, and the DC load 20 is charged.

  In mode 6, as shown in FIG. 35B, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the AC power supply 10 through the reactor 14b, the transistor T5, the transistor T3, the reactor 14a, and the switching element Q1n. At this time, energy is stored in each of the reactors 14a and 14b.

  In the period D when the AC voltage Va <0 and | Vac | ≧ Vo, the switching pattern Q1n, Q2p, Q3, Q4 is turned off, on, off, on mode 7, on, on. , Off, on mode 8 patterns.

  In the mode 7, as shown in FIG. 35 (c), based on the energy stored in the reactors 14a and 14b, from the negative electrode of the DC load 20, the transistor T4, the reactor 14a, the switching element Q2p, the reactor 14b, the transistor T5 The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In mode 8, as shown in FIG. 35 (d), a current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power supply 10 through the transistor T4, the reactor 14a, and the switching element Q1n. At this time, energy is stored in the reactor 14a. Further, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the transistor T5. At this time, energy is stored in the reactor 14b and the DC load 20 is charged.

  Therefore, according to the eleventh embodiment, when the AC voltage Vac ≧ 0 and | Vac | <Vo, the boost control can be performed by switching the transistor T4. When AC voltage Vac ≧ 0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1p. When AC voltage Vac <0 and | Vac | <Vo, step-up control can be performed by switching transistor T3. When AC voltage Vac <0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1n.

(Twelfth embodiment)
In the twelfth embodiment, a charging process is performed. Hereinafter, differences from the third embodiment will be described with reference to FIGS. FIG. 36 is a time chart corresponding to FIG. FIGS. 37A to 37C are circuit diagrams corresponding to FIGS. 9A to 9C. 38 (a) to 38 (c) are circuit diagrams corresponding to FIGS. 10 (a) to 10 (c). In this embodiment, when the AC voltage Vac ≧ 0, the transistors T3 and T6 perform rectification, and when the AC voltage Vac <0, the transistors T4 and T5 perform rectification. Further, when the alternating voltage Va <0, the switching element Q6 is switched in the third embodiment, but the switching element Q3 is switched in the present embodiment.

  As shown in FIG. 36, the switching patterns of the switching elements Q1p, Q1n, Q2p, Q2n are the same as those in the third embodiment. When AC voltage Vac ≧ 0, switching elements Q2n and Q6 are always turned on. Further, the switching element Q4 is switched with the duty ratio DR6, and the switching element Q3 is inverted and switched with respect to the switching element Q4. Further, when | Vac | ≧ Vo, the switching element Q1p is switched with the duty ratio DR5, and when | Vac | <Vo, the switching element Q1p is always turned on. On the other hand, when AC voltage Vac <0, switching elements Q2p and Q5 are always turned on. Further, the switching element Q3 is switched with the duty ratio DR6, and the switching element Q4 is inverted and switched with respect to the switching element Q3. Further, when | Vac | ≧ Vo, the switching element Q1n is switched with the duty ratio DR5, and when | Vac | <Vo, the switching element Q1n is always turned on.

  When the switching pattern is examined in detail during period A when AC voltage Vac ≧ 0 and | Vac | <Vo, switching elements Q1p, Q2n, Q3, and Q4 are in ON, ON, ON, OFF mode 1, ON, ON. , Off, on mode 2 patterns. Further, in the period B when the AC voltage Vac ≧ 0 and | Vac | ≧ Vo, the switching elements Q1p, Q2n, Q3, and Q4 are turned off, turned on, turned on, turned off, mode 3, turned on. , ON, ON, OFF mode 1, ON, ON, OFF, ON mode 2. Mode 1 and mode 2 have the same pattern as mode 1 and mode 2 in period A.

  In mode 1, as shown in FIG. 37A, a current flows from the negative electrode of the DC load 20 to the negative electrode of the AC power supply 10 through the transistor T6 and the reactor 14b. In addition, a current flows from the positive electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the switching element Q1p, the reactor 14a, and the transistor T3, and the DC load 20 is charged.

  In mode 2, as shown in FIG. 37 (b), a current flows from the positive electrode of the AC power supply 10 to the negative electrode of the AC power supply 10 through the switching element Q1p, the reactor 14a, the transistor T4, the transistor T6, and the reactor 14b. At this time, energy is stored in each of the reactors 14a and 14b.

  In mode 3, as shown in FIG. 37 (c), based on the energy stored in the reactors 14a and 14b, from the negative electrode of the DC load 20, the transistor T6, the reactor 14b, the switching element Q2n, the reactor 14a, the transistor T3 The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  In the period C when the AC voltage Va <0 and | Vac | <Vo, the switching pattern Q1n, Q2p, Q3, Q4 is turned on, on, off, on mode 4, on, on. There are two patterns of mode 5, on and off. Further, in the period D when the AC voltage Va <0 and | Vac | ≧ Vo, the switching elements Q1n, Q2p, Q3, and Q4 are turned off, on, off, on mode 6 and on when the switching pattern is examined in detail. , On, off, on mode 4 and on, on, on, off mode 5. Mode 4 and mode 5 have the same pattern as mode 4 and mode 5 in period C.

  In mode 4, as shown in FIG. 38A, current flows from the negative electrode of the DC load 20 to the positive electrode of the AC power supply 10 through the transistor T4, the reactor 14a, and the switching element Q1n. Further, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the DC load 20 through the reactor 14b and the transistor T5, and the DC load 20 is charged.

  In mode 5, as shown in FIG. 38B, a current flows from the negative electrode of the AC power supply 10 to the positive electrode of the AC power supply 10 through the reactor 14b, the transistor T5, the transistor T3, the reactor 14a, and the switching element Q1n. At this time, energy is stored in each of the reactors 14a and 14b.

  In mode 6, as shown in FIG. 38 (c), based on the energy stored in the reactors 14a and 14b, from the negative electrode of the DC load 20, the transistor T4, the reactor 14a, the switching element Q2p, the reactor 14b, the transistor T5 The current flows to the positive electrode of the DC load 20 through the DC load 20, and the DC load 20 is charged.

  Therefore, according to the twelfth embodiment, when the AC voltage Vac ≧ 0, the boost control can be performed by switching the transistor T4. When AC voltage Vac ≧ 0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1p. When the AC voltage Vac <0, the boost control can be performed by switching the transistor T3. When AC voltage Vac <0 and | Vac | ≧ Vo, step-down control can be performed by switching switching element Q1n.

(Other embodiments)
In the first to third and seventh to twelfth embodiments, when one of the switching elements Q2p and Q2n is switched on and the other is switched off, as shown in FIG. You should turn on. Similarly, in the fourth to sixth embodiments, when one of the switching elements Q1p and Q1n is switched on and the other is switched off, the other is preferably turned on before the other is turned off. If it does in this way, the return route of the electric current which flows from reactor 14a, 14b will always be ensured. Therefore, it is possible to suppress the generation of an induced voltage in reactors 14a and 14b, and to suppress a surge voltage associated with the induced voltage.

  As shown in FIG. 40, the reactors 14a and 14b are connected between the middle of each bridge of the full bridge circuit 15 and both ends of the pair of switching elements Q1p and Q1n included in the half bridge circuit 13, respectively. May be.

  As shown in FIG. 41, the reactor 14 may be a reactor 14 'configured with two windings in the same porcelain circuit.

  -As shown in FIG. 42, the reactor 14 may arrange | position the reactors 14a and 14b collectively in the position of the reactor 14a.

  -As shown in FIG. 43, the reactor 14 may arrange | position the reactors 14a and 14b collectively in the position of the reactor 14b.

  -Transistor T3-6 may be IGBT.

  DESCRIPTION OF SYMBOLS 12 ... Filter circuit, 13 ... Half bridge circuit, 14 ... Reactor, 15 ... Full bridge circuit, 16 ... Smoothing capacitor, 17 ... Voltage sensor, 18 ... Current sensor, 19 ... Voltage sensor, 21a, 21b ... DC side connection terminal, DESCRIPTION OF SYMBOLS 30 ... Control apparatus, 40 ... Power converter, Q1p, Q1n, Q2p, Q2n ... Reverse blocking type IGBT, Q3-6 ... Switching element.

Claims (13)

A smoothing capacitor (16) connected to a pair of DC side connection terminals (21a, 21b);
A full bridge circuit (15) connected to a connection point between the pair of DC side connection terminals and the smoothing capacitor and configured by four switching elements (Q3 to 6);
A filter circuit (12) connected to the pair of AC side connection terminals (11a, 11b);
Two pairs of reverse blocking IGBTs (Q1p, Q1n, Q2p, Q2n) connected to the connection point of the pair of AC side connection terminals and the filter circuit and connected in antiparallel to each other are connected in series. Half bridge circuit (13),
A reactor (14) connected between each bridge of the full bridge circuit and both ends of the pair of reverse blocking IGBTs of the half bridge circuit;
DC voltage detecting means (19) for detecting a DC voltage applied between the pair of DC side connection terminals;
AC voltage detection means (17) for detecting an AC voltage applied between the pair of AC side connection terminals;
Current detection means (18) for detecting a current flowing through the reactor;
Four switching elements included in the full bridge circuit and four reverse blocking types included in the half bridge circuit based on detection values of the DC voltage detection means, the AC voltage detection means, and the current detection means. And a control device (30) for switching control of the IGBT. The four switching elements are first to fourth switching elements,
The four reverse blocking IGBTs are first to fourth IGBTs,
The first switching element (Q3) and the second switching element (Q4) are connected in series,
The third switching element (Q5) and the fourth switching element (Q6) are connected in series,
The first switching element and the third switching element are connected to the positive electrode side of the pair of DC side connection terminals,
The second switching element and the fourth switching element are connected to the negative electrode side of the pair of DC side connection terminals,
The middle of each bridge is a connection point between the first switching element and the second switching element, and a connection point between the third switching element and the fourth switching element,
The emitter terminal of the first IGBT (Q1p) and the collector terminal of the second IGBT (Q2p) are connected, and the collector terminal of the first IGBT is the positive terminal of the pair of AC side connection terminals. The emitter terminal of the second IGBT is connected to the negative electrode side of the pair of AC side connection terminals,
The third IGBT (Q1n) is connected in antiparallel to the first IGBT,
The power converter according to claim 1 with which said 4th IGBT (Q2n) is connected to said 2nd IGBT in antiparallel. Both ends of a DC load (20) are connected to the pair of DC side connection terminals,
Both ends of the AC power source (10) are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detection means is positive, the fourth IGBT is always turned on, the first IGBT is switched at the first duty ratio, and the second switching element Is switched at the second duty ratio,
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the second IGBT is always turned on, the third IGBT is switched at the first duty ratio, and the fourth switching is performed. The power conversion device according to claim 2, wherein an element is switched at the second duty ratio. Both ends of a DC load are connected to the pair of DC side connection terminals,
Both ends of the AC power supply are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detection means is positive, the fourth IGBT is always turned on, and the absolute value of the AC voltage is obtained from the DC voltage detected by the DC voltage detection means. Is larger, the first IGBT is switched at a third duty ratio. When the absolute value of the AC voltage is smaller than the DC voltage, the first IGBT is always turned on and the second switching is performed. Switching the element at the fourth duty ratio;
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the second IGBT is always turned on, and the absolute value of the AC voltage is determined from the DC voltage detected by the DC voltage detection means. Is larger, the third IGBT is switched at the third duty ratio, and when the absolute value of the AC voltage is smaller than the DC voltage, the third IGBT is always turned on and the fourth IGBT is switched on. The power conversion device according to claim 2, wherein a switching element is switched at the fourth duty ratio. Both ends of a DC load are connected to the pair of DC side connection terminals,
Both ends of the AC power supply are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detection means is positive, the fourth IGBT is always turned on, and the absolute value of the AC voltage is obtained from the DC voltage detected by the DC voltage detection means. Is also switched when the first IGBT is switched at a fifth duty ratio and the second switching element is switched at a sixth duty ratio, and when the absolute value of the AC voltage is smaller than the DC voltage, Always turning on the first IGBT and switching the second switching element at the sixth duty ratio;
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the second IGBT is always turned on, and the absolute value of the AC voltage is determined from the DC voltage detected by the DC voltage detection means. When the third IGBT is switched at the fifth duty ratio and the fourth switching element is switched at the sixth duty ratio, and the absolute value of the AC voltage is smaller than the DC voltage. The power conversion device according to claim 2, wherein the third IGBT is always turned on and the fourth switching element is switched at the sixth duty ratio. Both ends of a DC load (20) are connected to the pair of DC side connection terminals,
Both ends of the AC power source (10) are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detecting means is positive, the fourth IGBT and the fourth switching element are always turned on, and the first IGBT is switched at the first duty ratio. , Switching the second switching element at a second duty ratio;
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the second IGBT and the third switching element are always turned on, and the third IGBT is switched at the first duty ratio. The power converter according to claim 2, wherein the first switching element is switched at the second duty ratio. Both ends of a DC load are connected to the pair of DC side connection terminals,
Both ends of the AC power supply are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detection means is positive, the fourth IGBT and the fourth switching element are always turned on, and the absolute value of the AC voltage is the DC voltage detection means. The first IGBT is switched at a third duty ratio when the voltage is larger than the DC voltage detected by the first voltage, and when the absolute value of the AC voltage is smaller than the DC voltage, the first IGBT is always turned on. And switching the second switching element with a fourth duty ratio,
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the second IGBT and the third switching element are always turned on, and the absolute value of the AC voltage is the DC voltage detection means. The third IGBT is switched at the third duty ratio when the DC voltage is greater than the DC voltage detected by the first duty ratio. When the absolute value of the AC voltage is smaller than the DC voltage, the third IGBT is always switched. The power converter according to claim 2, wherein the power converter is turned on and the first switching element is switched at the fourth duty ratio. Both ends of a DC load are connected to the pair of DC side connection terminals,
Both ends of the AC power supply are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detection means is positive, the fourth IGBT and the fourth switching element are always turned on, and the second switching element is switched at the sixth duty ratio. When the absolute value of the AC voltage is larger than the DC voltage detected by the DC voltage detecting means, the first IGBT is switched at a fifth duty ratio, and the absolute value of the AC voltage is changed to the DC voltage. When the voltage is smaller than the voltage, the first IGBT is always turned on,
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the second IGBT and the third switching element are always turned on, and the first switching element is switched at the sixth duty ratio. And when the absolute value of the AC voltage is larger than the DC voltage detected by the DC voltage detecting means, the third IGBT is switched at the fifth duty ratio, and the absolute value of the AC voltage is The power conversion device according to claim 2, wherein when the voltage is smaller than the DC voltage, the third IGBT is always turned on. Both ends of a DC power source (60) are connected to the pair of DC side connection terminals,
Both ends of the AC load (50) are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detection means is positive, the third IGBT and the fourth switching element are always turned on, and the second IGBT is switched at a seventh duty ratio. Switching the first switching element with an eighth duty ratio;
When the polarity of the AC voltage detected by the AC voltage detection means is negative, the first IGBT and the second switching element are always turned on, and the fourth IGBT is switched at the seventh duty ratio. The power converter according to claim 2, wherein the third switching element is switched at the eighth duty ratio. Both ends of a DC power source are connected to the pair of DC side connection terminals,
Both ends of the AC load are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detecting means is positive, the third IGBT and the fourth switching element are always turned on, and the DC voltage detected by the DC voltage detecting means is When smaller than the absolute value of the AC voltage, the second IGBT is switched at a ninth duty ratio and the first switching element is always turned on, and the DC voltage is larger than the absolute value of the AC voltage. When the first switching element is switched at the 10th duty ratio,
When the polarity of the AC voltage detected by the AC voltage detecting means is negative, the first IGBT and the second switching element are always turned on, and the DC voltage detected by the DC voltage detecting means is When smaller than the absolute value of the AC voltage, the fourth IGBT is switched at the ninth duty ratio and the third switching element is always turned on, and the DC voltage is higher than the absolute value of the AC voltage. 3. The power conversion device according to claim 2, wherein when larger, the third switching element is switched at the tenth duty ratio. 4. Both ends of a DC power source are connected to the pair of DC side connection terminals,
Both ends of the AC load are connected to the pair of AC side connection terminals,
The controller is
When the polarity of the AC voltage detected by the AC voltage detecting means is positive, the third IGBT and the fourth switching element are always turned on, and the DC voltage detected by the DC voltage detecting means is When the AC voltage is smaller than the absolute value, the second IGBT is switched at the 11th duty ratio and the first switching element is switched at the 12th duty ratio, and the DC voltage is the absolute voltage of the AC voltage. If greater than the value, the first switching element is switched at the twelfth duty ratio;
When the polarity of the AC voltage detected by the AC voltage detecting means is negative, the first IGBT and the second switching element are always turned on, and the DC voltage detected by the DC voltage detecting means is When the absolute value of the AC voltage is smaller, the fourth IGBT is switched at the eleventh duty ratio and the third switching element is switched at the twelfth duty ratio, and the DC voltage is the AC voltage. 3. The power conversion device according to claim 2, wherein the third switching element is switched at the twelfth duty ratio when the absolute value is larger than the absolute value of.   The power converter according to claim 3, wherein the other IGBT is turned on before one of the second IGBT and the fourth IGBT is turned off.   The power converter according to any one of claims 9 to 11, wherein one of the first IGBT and the third IGBT is turned on before the other is turned off.

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