JP2013038921A - Step-up chopper circuit, and power supply device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a step-up chopper circuit that can use a transistor with a withstanding voltage of around half or less than that of a conventional one as a switching transistor.SOLUTION: In a step-up chopper circuit, a coil L1 and transistors Q1, Q2 are connected in series with a DC power supply, a series circuit including a diode D1 and a capacitor C1 is connected with both ends of the transistor Q1; and a series circuit including a diode D2 and a capacitor C2 is connected with both ends of the transistor Q2. The transistors Q1, Q2 are turned on to accumulate energy in the coil 1; only the transistor Q1 is then turned on to charge the capacitor C2 with the energy accumulated in the coil 1 through the path composed of the coil L1, the transistor Q1, the capacitor C2, and the diode D2; the transistors Q1, Q2 are turned on again to accumulate energy in the coil 1; and only the transistor Q2 is then turned on to charge the capacitor C1 with the energy accumulated in the coil 1 through the path composed of the coil L1, the diode D1, the capacitor C1, and the transistor Q2.

Description

  The present invention relates to a boost chopper circuit and a power supply device including the same.

  A power supply device including a conventional boost chopper will be described with reference to FIG. 7. This power supply device includes a commercial power supply 1, a rectifier circuit 2 that smoothes the AC power supplied from the commercial power supply 1 by full-wave rectification, A boost chopper circuit 3 boosts the output voltage of the rectifier circuit 2 and an inverter circuit 4 that supplies the output of the boost chopper circuit 3 to a load.

  The step-up chopper circuit 3 includes a step-up coil 31, a switching transistor 32, a diode 33, and a capacitor.

  In such a step-up chopper circuit 3, the DC voltage obtained by rectifying the voltage of the commercial power source 1 with the rectifier circuit 2 is about 280-300V. At this time, the voltage across the capacitor 34 may be required to be about 1500V. When the voltage across the capacitor 34 is boosted to about 1500V, the switching transistor 32 requires a high breakdown voltage transistor of about 2500V or 3000V.

  However, the type of such a high withstand voltage transistor is limited and the price is high, and the price of the step-up chopper circuit is high, making it difficult to adopt as a product.

JP 2008-084627 A

  In the present invention, even when a voltage across the capacitor of about 1500 V, for example, is required, a step-up chopper circuit that can use a transistor having a breakdown voltage of at least half that of the high breakdown voltage described above as a switching transistor and Providing a power supply device having this is a problem to be solved.

In the boost chopper circuit according to the present invention, a coil is connected to at least one of a positive side and a negative side of a DC power source, and a current inflow portion of the first transistor is connected to the positive side of the DC power source via the coil or directly. ,
A current inflow portion of the second transistor is connected in common to the current outflow portion of the first transistor, and the current outflow portion of the second transistor is connected to the negative side of the DC power supply via the coil or directly;
An anode of a first diode is connected to a current inflow portion of the first transistor, a cathode of the first diode is connected to one electrode of a first capacitor;
Connecting the other pole of the first capacitor to a common connection part of the current outflow part of the first transistor and the current inflow part of the second transistor, and connecting one electrode of the second capacitor to the common connection part;
The other pole of the second capacitor is connected to an anode of a second diode, and a cathode of the second diode is connected to a current outflow portion of the second transistor.

  As one aspect of the present invention, the coil may be provided not between the positive side of the DC power supply and the current inflow portion of the first transistor, but between the negative side of the DC power supply and the current outflow side of the second transistor. You may provide in both.

  When both the coils are provided, it is preferable that these both coils are tightly coupled.

  Note that a power supply apparatus including a single-phase three-level inverter in the boost output unit of the boost chopper circuit can be configured.

  In addition, a power supply device including a three-phase three-level inverter in the boost output unit of the boost chopper circuit can be configured.

  The boost chopper circuit includes a plurality of boost chopper circuits, each of which is connected in parallel between a pair of voltage input sections for boosting and a pair of voltage output sections for outputting the boosted voltage. A device can be configured. In this power supply device, it is preferable to separate the common connection portions of the first and second capacitors in each boost chopper circuit.

  In the step-up chopper circuit of the present invention, since there are two capacitors and the voltage across each capacitor can be shared by the two switching transistors corresponding to the two capacitors, even if about 1500 V is required for both capacitors as a whole, Compared with a high withstand voltage transistor of about 2500 V or about 3000 V, which is conventionally required, a transistor with a withstand voltage of at least half or less can be used.

FIG. 1 is a circuit diagram of a boost chopper circuit according to an embodiment of the present invention. FIG. 2 is a circuit diagram for explaining the operation of the step-up chopper circuit of FIG. FIG. 3 is a circuit diagram showing a modification of the boost chopper circuit. FIG. 4 is a circuit diagram of a power supply device including the step-up chopper circuit and the single-phase three-level inverter according to the embodiment. FIG. 5 is a circuit diagram of a power supply device including the boost chopper circuit and the three-phase three-level inverter according to the embodiment. FIG. 6 is a circuit diagram of a power supply device in which a plurality of boost chopper circuits according to the embodiment are connected in parallel. FIG. 7 is a circuit diagram of a conventional boost chopper circuit.

  Hereinafter, a boost chopper circuit according to an embodiment of the present invention will be described with reference to the accompanying drawings. The boost chopper circuit of the embodiment will be described with reference to FIG. 1. The boost chopper circuit includes a coil L1, switching transistors Q1 and Q2, diodes D1 and D2, and capacitors C1 and C2. In FIG. 1, a circuit for controlling on / off of the first and second switching transistors Q1, Q2 is not shown.

  IN1 is a terminal to which the positive side of a DC power supply (not shown) is connected, and IN2 is a terminal to which the negative side of the DC power supply is connected. A DC power supply (not shown) is connected to the terminals IN1 and IN2, and a load (not shown) is connected to the terminals OUT1 and OUT2. Note that this DC power supply includes a case where the output voltage has pulsation and a case where there is no pulsation.

  The collector (current inflow portion) of the first switching transistor Q1 is connected to the positive side of the DC power supply via the terminal IN1 via the coil L1. The emitter (current outflow portion) of the first switching transistor Q1 is commonly connected to the collector (current inflow portion) of the second switching transistor Q2. The emitter (current outflow portion) of the second switching transistor Q2 is connected to the negative side of the DC power supply via the terminal IN2. The transistor of the embodiment is a bipolar type (including IGBT, etc.), but the present invention is not limited to this type of transistor, and may be another type of transistor such as an FET. The first and second switching transistors Q1 and Q2 are power transistors having a large withstand voltage and large current capacity, and current flows from one terminal by control of a control input unit such as a base or a gate in these transistors. The one terminal side is defined as a current inflow portion, and the other terminal side when current flows out to the other terminal is defined as a current outflow portion.

  The anode of the first diode D1 is connected to the connection between the collector of the first switching transistor Q1 and the coil L1. The cathode of the first diode D1 is connected to one electrode of the first capacitor C1. The other pole of the first capacitor C1 is connected to the emitter of the first switching transistor Q1. The collector of the second switching transistor Q2 is connected to one pole of the second capacitor C2. The other pole of the second capacitor C2 is connected to the anode of the second diode D2. The cathode of the second diode D2 is connected to the current inflow portion IN2 together with the emitter of the second transistor Q2.

  A controller for turning on and off the first and second switching transistors Q1 and Q2 is not shown. This control unit can control the operation of the step-up chopper circuit described with reference to FIG. This control unit turns on and off the first and second switching transistors Q1 and Q2 with a required duty.

  The operation of the boosting chopper circuit will be described with reference to FIGS.

  The operation mode of the step-up chopper circuit changes depending on the voltage level of the DC power supply, the voltage level of the second capacitor C2, and the voltage level of the first capacitor C1.

  In some cases, the first and second switching transistors Q1 and Q2 are both turned off, and the voltage level of the DC power supply is equal to the voltage level of the second capacitor C2 and the voltage level of the first capacitor C1. This is the sleep mode, and the operation mode is 0 (FIG. 2A).

  Regardless of the sum of the voltage level of the second capacitor C2 and the voltage level of the first capacitor C1, there are four operation modes described below.

  The first and second switching transistors Q1 and Q2 are both turned on, and the operation mode 1 in which the energy of the DC power source is released and accumulated in the coil L1 (FIG. 2B).

  An operation mode 2 in which the first switching transistor Q1 is turned on and the second switching transistor Q2 is turned off, and the energy of the DC power supply and the coil L1 is released and stored and charged in the second capacitor C2 (FIG. 2C).

  Operation mode 3 in which the second switching transistor Q2 is turned on and the first switching transistor Q1 is turned off, and the energy of the DC power supply and the coil L1 is released and stored and charged in the first capacitor C1 (FIG. 2 (d)).

  The first switching transistor Q1 and the second switching transistor Q2 are both turned off, and the energy is discharged from the DC power source and the coil L1, and is stored and charged in the first capacitor C1 and the second capacitor C2. )).

  Further, when the voltage level of the DC power supply is higher than the voltage level of the second capacitor C2 and the voltage level of the first capacitor C1, there are two operation modes described below.

  The first switching transistor Q1 is turned on and the second switching transistor Q2 is turned off, so that the energy of the DC power source is released and accumulated in the coil L1 and also accumulated and charged in the second capacitor C2. Same as FIG. 2 (c)).

  The second switching transistor Q2 is turned on, the first switching transistor Q1 is turned off, and the energy of the DC power supply is released and accumulated in the coil L1 and also accumulated and charged in the first capacitor C1 (shown in the figure). Same as FIG. 2 (d)).

  When the height of the DC power supply is higher than the sum of the voltage of the second capacitor C2 and the voltage of the first capacitor C1, it does not exist constantly.

  In the operation mode 0, no current flows as shown in FIG.

  In the operation mode 1, both the first and second switching transistors Q1 and Q2 are turned on. As a result, as shown in FIG. 2B, a current flows through a DC power source (not shown), a path (1) indicated by an arrow formed by the coil L1 and the first and second switching transistors Q1 and Q2, and the DC power source The energy is released from the gas and accumulated in the coil L1.

  In the operation mode 2, in order to charge the second capacitor C2, the first switching transistor Q1 is turned on and the second switching transistor Q2 is turned off. As shown in FIG. 2 (c), current flows through a path (2) indicated by an arrow composed of a DC power source (not shown), a coil L1, a first switching transistor Q1, a second capacitor C2, and a second diode D2. The energy of the DC power supply and the coil L1 is released, the energy is stored in the second capacitor C2, and the second capacitor C2 is charged.

  In the operation mode 3, in order to charge the first capacitor C1, the second switching transistor Q2 is turned on and the first switching transistor Q1 is turned off. As shown in FIG. 2D, current flows through a path (3) indicated by an arrow composed of a DC power source (not shown), a coil L1, a first diode D1, a first capacitor C1, and a second switching transistor Q2. The energy of the DC power source and the coil L1 is released, the energy is stored in the first capacitor C1, and the first capacitor C1 is charged.

  In the operation mode 4, both the first and second switching transistors Q1 and Q2 are turned off. As a result, as shown in FIG. 2 (e), a current flows through a path (4) indicated by an arrow composed of a DC power source (not shown), the coil L1, and the first and second switching transistors Q1 and Q2, and the DC The energy of the power source and the coil L1 is released, and the energy is stored and charged in the first and second capacitors C1 and C2.

  The operation mode 5 is a mode when the voltage of the DC power supply is higher than the voltage of the second capacitor C2. As shown in FIG. 2C, the first switching transistor Q1 is turned on, the second switching transistor Q2 is turned off, the DC power source (not shown), the coil 1, the first switching transistor Q1, the second capacitor C2, the second A current flows through the path (2) of the arrow formed by the two diodes D2, and the energy of the DC power supply is released and accumulated in the coil LI, and also accumulated and charged in the second capacitor C2.

  The operation mode 6 is a mode when the voltage of the DC power supply is higher than the voltage of the first capacitor C1. As shown in FIG. 2D, the second switching transistor Q2 is turned on, the first switching transistor Q1 is turned off, a DC power supply (not shown), a coil L1 and a first diode D1, a first capacitor C1, a second A current flows through the path (3) of the arrow formed by the switching transistor Q2, and the energy of the DC power source is released and accumulated in the coil LI and also accumulated and charged in the first capacitor C1.

  By repeating such an operation mode, the total voltage between both ends of the first and second capacitors C1 and C2 is boosted. However, between the collector and emitter of the first switching transistor Q1, between the both ends of the first capacitor C1. A voltage is applied, and a voltage across the second capacitor C2 is applied between the collector and emitter of the second switching transistor Q2.

  Accordingly, assuming that the capacitances of the first and second capacitors C1 and C2 are the same, the first and second switching transistors Q1 and Q2 can be transistors having a breakdown voltage of about half of the total voltage. This means that a withstand voltage about half that required for a switching transistor used in a conventional step-up chopper circuit is sufficient.

  In FIG. 1, the coil L1 is only connected to the positive side of the DC power supply. However, as shown in FIG. 3A, only the coil L2 is connected to the negative side of the DC power supply. Alternatively, as shown in FIG. 3B, the coils L1 and L2 may be connected to both the positive side and the negative side of the DC power supply. In FIG. 3B, the coils L1 and L2 are preferably tightly coupled.

  FIG. 4 is a circuit diagram of a power supply device that combines a boost chopper circuit and a single-phase three-level inverter. 1 is a step-up chopper circuit, 2 is a single-phase three-level inverter, and 3 is a load.

  The step-up chopper circuit 1 is a circuit similar to that shown in FIG. 1, and the reference numerals are also shown in FIG. However, this step-up chopper circuit 1 is shown by coils L1 and L2 that are tightly coupled to the terminals IN1 and IN2, respectively. However, this tight coupling is not a necessary requirement, and as shown in FIG. As shown in FIG. 3A, the coil L2 is provided only on the terminal IN2 side, or the coils L1 and L2 are tightly coupled to both the terminals IN1 and IN2 as shown in FIG. 3B. It can be used even if it is not provided.

  The single-phase three-level inverter 2 includes four transistors S1u-S4u, four more transistors S1v-S4v, diodes D1u-D4u and D1v-D4v connected in reverse parallel to the individual transistors, and two transistors above and below each other. S1u, S2u; S3u, S4u; S1v, S2v; S3v, S4v connection midpoint ad and diode D5u, which connects the first and second capacitors C1, C2 of boost chopper circuit 1 to the connection midpoint O D6u; composed of D5v and D6v. Of the four transistors S1u-S4u, the connection midpoint U of the upper two transistors S1u, S1u and the lower two transistors S3u, S4u, and the upper two transistors S1v, S1v of the four transistors S1v-S4v A load 3 is connected between a connection middle point V of the lower two transistors S3v and S4v.

  In this single-phase three-level inverter 2, if the voltage of the capacitors C 1 and C 2 is Ed / 2, the output voltage Euv between U and V is ± Ed / 2 by PWM control on the transistor, although details are omitted. Control can be made so that three values of 0 can be taken.

  In this power supply device, when the single-phase three-level inverter 2 is connected corresponding to the neutral point O of the first and second capacitors C1 and C2 of the boost chopper circuit 1, the transistors in the single-phase three-level inverter 2 are connected. A low withstand voltage can be used.

  FIG. 5 shows a circuit diagram of a power supply device combining a boost chopper circuit and a three-phase three-level inverter. 1 is a step-up chopper circuit, 2a is a three-phase three-level inverter, and 3a is a three-phase load (three-phase motor).

  The step-up chopper circuit 1 is a circuit similar to that shown in FIG. 1, and the reference numerals are also shown in FIG. However, this step-up chopper circuit 1 is shown by coils L1 and L2 that are tightly coupled to the terminals IN1 and IN2, respectively. However, this tight coupling is not a necessary requirement, and as shown in FIG. As shown in FIG. 3A, the coil L2 is provided only on the terminal IN2 side, or the coils L1 and L2 are tightly coupled to both the terminals IN1 and IN2 as shown in FIG. 3B. It can be used even if it is not provided.

  The three-phase three-level inverter 2a includes four transistors S1u-S4u, four transistors S1v-S4v, four transistors S1w-S4w, and diodes D1u-D4u, D1v-D4v connected in reverse parallel to the individual transistors. , D1w-D4w, two upper and lower transistors S1u, S2u; S3u, S4u; S1v, S2v; S3v, S4v; S1w, S2w; 1 and diodes D5u, D6u; D5v, D6v; D5w, D6w that connect the connection midpoint O of the second capacitors C1, C2. Of the four transistors S1u-S4u, the connection midpoint U of the upper two transistors S1u, S1u and the lower two transistors S3u, S4u, and the upper two transistors S1v, S1v of the four transistors S1v-S4v Three phases between the connection middle point V of the lower two transistors S3v and S4v and the connection middle point W of the upper two transistors S1w and S1w and the lower two transistors S3w and S4w among the four transistors S1w to S4w A three-phase load 3a such as a motor is connected.

  In this power supply device, when the three-phase three-level inverter 2a is connected corresponding to the neutral point O of the first and second capacitors C1 and C2 of the boost chopper circuit 1, the transistors in the three-phase three-level inverter 2a are connected. A low withstand voltage can be used.

  FIG. 6 shows a power supply device in which a plurality of step-up chopper circuits are connected in parallel. This power supply apparatus has boost chopper circuits 5 and 6 having the same circuit configuration. Each step-up chopper circuit 5 and 6 includes coils L1 and L2, first and second switching transistors Q1 and Q2, first and second diodes D1 and D2, and first and second capacitors C1 and C2, respectively. The coils L1 and L2 are connected in parallel between the terminals IN1 and IN2, and the first and second capacitors C1 and C2 are connected in parallel between the terminals OUT1 and OUT2. In this power supply device, the coils L1 and L2 in each of the step-up chopper circuits 5 and 6 are tightly coupled, and the connection midpoints O1 and O2 of the first and second capacitors C1 and C2 are not connected and separated. Has been.

L1 Coil Q1, Q2 Switching element D1, D2 Diode C1, C2 Capacitor

Claims (7)

A coil is connected to at least one of a positive side or a negative side of the DC power source, and a current inflow portion of the first transistor is connected to the positive side of the DC power source via the coil or directly;
A current inflow portion of the second transistor is connected in common to the current outflow portion of the first transistor, and the current outflow portion of the second transistor is connected to the negative side of the DC power supply via the coil or directly;
An anode of a first diode is connected to a current inflow portion of the first transistor, a cathode of the first diode is connected to one electrode of a first capacitor;
Connecting the other pole of the first capacitor to a common connection part of the current outflow part of the first transistor and the current inflow part of the second transistor, and connecting one electrode of the second capacitor to the common connection part;
The other pole of the second capacitor was connected to the anode of a second diode, and the cathode of the second diode was connected to the current outflow portion of the second transistor.
A step-up chopper circuit.   A plurality of step-up chopper circuits according to claim 1, wherein each step-up chopper circuit includes a pair of power supply side terminal portions to which a positive side and a negative side of a DC power supply are connected, and a pair of load sides that output a boosted voltage to a load. A power supply device connected in parallel with a terminal portion.   3. The power supply device according to claim 2, wherein each of the step-up chopper circuits has a coil connected to both of the pair of power supply side terminal portions and the two coils are closely coupled to each other.   4. The power supply device according to claim 2, further comprising a single-phase three-level inverter on a boost output side of each boost chopper circuit.   4. The power supply device according to claim 2, further comprising a three-phase three-level inverter on a boost output side of each boost chopper circuit.   A power supply apparatus comprising: the step-up chopper circuit according to claim 1; and a single-phase three-level inverter connected to a step-up output side of the step-up chopper circuit.   A power supply apparatus comprising: the step-up chopper circuit according to claim 1; and a three-phase three-level inverter connected to a step-up output side of the step-up chopper circuit.

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