JPWO2006098376A1 - Chopper circuit - Google Patents

Abstract

Two main reactors divided into two equivalents equivalent to one reactor and one pole connected to one end of a series connection of the main reactor, and the other pole connected directly to one voltage terminal of the DC power source A main switch, a series connection of a snubber diode and a snubber capacitor, connected between both poles of the main switch, a connection point of the snubber diode and the snubber capacitor, and a connection point of a series connection of the two main reactors And an auxiliary switch connected between them to form a snubber auxiliary ZVZCT (Snubber-Assisted Zero Voltage and Zero Current Transition chopper) chopper circuit. The above configuration eliminates the heat loss generated in the reactor provided for soft switching, improves the conversion efficiency, prevents the overcurrent overvoltage when the main switch is turned on and off, and prevents the overvoltage due to the reverse recovery of the output diode. prevent.

Description

  The present invention relates to a chopper circuit that constitutes a power supply that performs DC conversion.

  For driving an electric vehicle such as a fuel cell vehicle, a high-efficiency, high-power chopper circuit that operates in an output range of 100 kW is used. Conventionally, hard switching converters are used in the field of electric vehicles.

  Low loss is required not only in fuel cell vehicles but also in the field of using semiconductor power conversion devices, so a chopper circuit by soft switching is required.

  Conventionally, a C bridge chopper circuit as shown in FIG. 30 is known as a high power chopper circuit. The C-bridge chopper circuit shown in the figure has a configuration using two switches and one capacitor, and is suitable for a large current application in that a large current can be cut off by a lossless snubber circuit and there is no loss.

However, this C-bridge chopper circuit has a problem that the overall power loss is large because the main switch and the diode are connected in series to the main circuit, and when the main switches S ₁ and S ₂ are turned on simultaneously, the output an overvoltage caused by a reverse recovery time of the recovery current of the diode D _3, that the charging voltage of the snubber capacitor are overlapped, a large overvoltage occurs, there is a problem that the output diode D ₃ may be damaged.

Accordingly, the inventors of the present application have proposed a quasi-resonant regenerating active snubber (QRAS) type chopper circuit (see, for example, Non-Patent Document 1). FIG. 31 shows an example of the configuration of this QRAS chopper circuit. In this QRAS chopper circuit comprises a main switch S ₁ and the auxiliary switch S _2, the configuration of the reactor SL ₁ to the main switch S ₁ are connected in series, by delaying the current flowing through the main switching S _1, the main switch S ₁ The current is set to zero at turn-on (FIG. 32).
Proceedings of the Conference of the Institute of Electrical Engineers of Japan, Tsuruma, Kamigami, Kawamura “High-efficiency, high-power chopper circuit QRAS” 2004-6

In the above-described QRAS chopper circuit, soft switching is realized by connecting the reactor SL ₁ to the main switch S _1. However, the conversion efficiency is reduced due to the heat loss generated by the internal resistance due to the current flowing through the reactor SL _1. There is a problem of doing.

In addition, there is a problem that the main switch S ₁ also generates an overcurrent overvoltage when the main switch S ₁ of the QRAS chopper circuit is turned on and off. The turn-off over-voltage of the main switch, the clamping voltage of the snubber capacitor (see voltage characteristics between 49.960~49.965sec in Figure 32 (indicated by V)) is applied to the main switch S ₁ as an overvoltage. Further, when the main switch S ₁ is turned on, an excessive current flows through the main switch S ₁ due to the reverse recovery of the output diode D ₅ (see the current characteristic of 49.940 sec in FIG. 32 (shown by I)).

Further, the reverse recovery of the output diode D _5, a large reverse spike voltage is generated in the output diode D ₅ (see voltage characteristics of 49.9400sec in Figure 33 (indicated by V)), is a risk that the output diode itself is damaged There is also the problem of being. It is to be 32 and 33 is the simulation results, Fig. 32 in 111 indicates the voltage of the main switch S _1, 211 represents a current of the main switch S _1, 113 in FIG. 33, the voltage of the output diode D ₅ Is shown.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described conventional problems, eliminate the heat loss that has conventionally occurred in the reactor provided for soft switching, and improve the conversion efficiency.

  Another object of the present invention is to prevent overcurrent overvoltage when the main switch is turned on.

Further, the present invention is intended to prevent overvoltage due to reverse recovery of the output diode D _5.

  In the present invention, two main reactors divided into two equivalently constituting one reactor, one pole is connected to one end of a series connection body of the main reactor, and the other pole is connected to one voltage terminal of a DC power source. A directly connected main switch, a series connection of a snubber diode and a snubber capacitor connected between both poles of the main switch, a connection point of the snubber diode and the snubber capacitor, and a series connection of two main reactors. A snubber auxiliary ZVZCT (Snubber-Assisted Zero Voltage and Zero Current Transition chopper) chopper circuit is configured.

  In order to make the current at the time of turning on the main switch zero, a conventional reactor is used, whereas the present invention has a configuration including an auxiliary switch, and the snubber capacitor is turned on by turning on the auxiliary switch. The voltage at the time of turn-on of the main switch is set to zero voltage, and a regenerative resonance between the snubber capacitor and the main reactor is generated via the auxiliary switch. By turning it on, the current due to this regenerative resonance is passed in a direction that cancels the main current of the main switch, so that the current and voltage of the main switch at the time of turn-on become zero.

  As a result, soft switching is performed at zero voltage and zero current when the main switch is turned on without using a reactor as in the conventional chopper circuit, thereby eliminating the heat loss and improving the conversion efficiency of the chopper circuit. In addition, overcurrent overvoltage can be prevented.

  In addition, by using the auxiliary switch to regenerate the charge accumulated in the output diode to the DC power supply, it is possible to prevent overvoltage due to reverse recovery of the output diode.

  The present invention can be applied to various chopper circuits such as a step-down type, a step-up type, a step-up / step-down type, a CUK type, a SEPIC type, and a ZETA type.

  When the present invention is applied to a step-up chopper circuit, a more detailed form is that a series of two divided main reactors equivalently constituting one reactor, one end of which is connected to a high potential side terminal of a DC power supply. Connected body, one pole connected to the other end of the series connection body of the main reactor, the other pole connected directly to the low voltage terminal of the DC power supply, and the output connected between both poles of the main switch A series connection body of a diode and an output smoothing capacitor, a series connection body of a snubber diode and a snubber capacitor, a connection point of the snubber diode and the snubber capacitor, connected between both poles of the main switch, and a series connection of two main reactors It is the structure provided with the auxiliary switch connected between the connection points of the body.

  When the auxiliary switch of the present invention is turned on, the charge stored in the output diode is passed through the main reactor on the DC power source side of the two main reactors in the direction opposite to the main current of the main reactor, Regenerate to power. As a result, in addition to preventing overvoltage due to reverse recovery of the output diode of the output diode, the direction of current flow to the main reactor is made opposite to the main current of the main reactor, thereby reducing heat loss generated in the main reactor. Can do.

  When the main switch of the present invention is turned on, the charge accumulated in the snubber capacitor is transferred to the main reactor on the DC power source side of the two main reactors by regenerative resonance between the snubber capacitor and the main reactor connected to the DC power source side. Then, it flows in the direction opposite to the main current of the main reactor and regenerates to the DC power supply. Heat loss generated in the main reactor can be reduced by setting the regenerative current passed through the main reactor in the opposite direction to the main current of the main reactor.

When the main switch is turned on, in order to perform soft switching with zero current and zero voltage, the main switch is turned on after the auxiliary switch is turned on. As a result, the main switch can be turned on from a zero voltage and zero current state.
As another form of the chopper circuit of the present invention, the main reactor can be integrally formed by a coupled reactor having a mutual inductance.

  Another embodiment of the chopper circuit of the present invention includes an output clamp diode between the snubber capacitor and the output capacitor. With this configuration, both hard switching and soft switching operations can be used together.

  Another embodiment of the chopper circuit according to the present invention includes a main reactor having one end connected to one terminal of the DC power supply, one pole connected to the other end of the main reactor, and the other pole connected to the low voltage terminal of the DC power supply. The main switch connected directly to the main switch, the series connection of the output diode and the output smoothing capacitor connected between the poles of the main switch, the capacitor connected between the poles of the main switch, the high potential side of the capacitor and the DC power supply It is set as the structure provided with the serial connection body of the regeneration reactor and auxiliary switch which were connected between the high potential side terminals. According to this embodiment, a snubber diode and a snubber capacitor can be dispensed with, and a capacitor connected between both poles of the main switch can be small in capacity, and can be operated even in a mode in which a voltage remains.

  Another embodiment of the chopper circuit according to the present invention includes a series connection body of two divided main reactors, one end of which is equivalent to one reactor connected to one terminal of a DC power source, and one pole. A main switch connected to the other end of the series connection of the main reactor, the other pole connected directly to the low voltage terminal of the DC power supply, and a series of output diode and output smoothing capacitor connected between both poles of the main switch The connection body includes a connection point between the other end of the series connection body of the main switch and the main reactor, and an auxiliary switch directly connected between the connection point of the series connection body of the two main reactors.

  In another embodiment of the chopper circuit of the present invention, a main reactor having one end connected to one terminal of a DC power source, one pole connected to the other end of the main reactor, and the other pole connected to the DC power source. The main switch directly connected to the low voltage terminal of the main switch, the series connection of the output diode and the output smoothing capacitor, connected between both poles of the main switch, and the other end of the series connection of the main switch and the main reactor It is set as the structure provided with the serial connection body of the regeneration reactor and auxiliary switch which were connected between the point and the high potential side terminal of DC power supply.

  The two forms described above are configurations using the stray capacitance of the main switch, and soft switching is possible only with the three elements of the two switches and the main reactor.

  Another embodiment of the chopper circuit according to the present invention includes a series connection body of two divided main reactors, one end of which is equivalent to one reactor connected to one terminal of a DC power source, and one pole. A main switch in which the other end of the main reactor is connected and the other pole is directly connected to the low voltage terminal of the DC power source, and a series connection body of an output diode and an output smoothing capacitor, which is connected between both poles of the main switch And a capacitor that directly connects both poles of the main switch, and an auxiliary switch that directly connects between the high potential side of the capacitor and the connection point of the series connection body of the two main reactors. According to this embodiment, the snubber diode can be eliminated.

  In another embodiment of the chopper circuit according to the present invention, the main switch is switched between hard switching and soft switching by gate control of the auxiliary switch.

  Another embodiment of the chopper circuit according to the present invention includes a series connection body of two divided main reactors, one end of which is equivalent to one reactor connected to one terminal of a DC power source, and one pole. A main switch connected to the other end of the series connection body of the main reactor and the other pole connected directly to the low voltage terminal of the DC power source, and a series of an output diode and an output smoothing capacitor between both poles of the main switch A connecting body, a snubber capacitor connected between the poles of the main switch, a connection point between the high potential of the snubber capacitor, and an auxiliary switch that directly connects between the connection point of the series connection body of the two main reactors. It is set as the structure provided. According to this embodiment, the snubber diode can be eliminated.

  In the form of the chopper circuit of the present invention, the main reactor can be provided on the high potential side or the low potential side of the DC power supply.

  In the step-up / step-down type of the chopper circuit of the present invention, one pole of one main switch is connected to the high potential side terminal of the DC power supply, and one pole of the other main switch is connected to the low potential side terminal of the DC power supply. Connected to the other pole of the two main switches, and a snubber connected in the forward direction from the high potential of the DC power supply to the low potential between the two poles of each main switch. Two series connection bodies of a diode and a snubber capacitor, and one end connected to the connection point of the two main switches and the other end connected to a terminal of a DC power source are divided into two equivalently constituting one reactor. A series connection body of two main reactors, two auxiliary switches each connected between two connection points of a snubber diode and a snubber capacitor and a connection point of two series connection bodies of the main reactors

  In another form of the chopper circuit of the present invention, a series connection body of a snubber diode and a snubber capacitor is connected between both poles of the main switch, and one pole of the main switch is connected to a series connection body of two main reactors or equivalent. Are connected to one end of one main reactor connected in series with two inductors and one pole of a diode, the other pole of the main switch is directly connected to one voltage terminal of a DC power source, and the other pole of the output diode is connected. And an auxiliary switch in which the snubber diode is connected between a connection point of a snubber capacitor and a connection point of a series connection body of the main reactor or a connection point of two inductances. Before the main switch is turned on, the auxiliary switch is turned on by soft switching by the main reactor, and the accumulated charge is After the reverse blocking characteristic of the diode is restored by soft switching, the main switch is turned on by soft switching by the resonance operation of the snubber capacitor and the main reactor, and the main switch is turned off by soft switching by the snubber capacitor. The switch is configured to be turned off by soft switching at zero current.

  As described above, according to the present invention, by turning on the auxiliary switch, the voltage of the snubber capacitor is set to zero voltage, and the voltage at the turn-on time of the main switch is set to zero voltage. By turning on the auxiliary switch, a regenerative resonance between the snubber capacitor and the main reactor is generated via the auxiliary switch, and the current due to this regenerative resonance is passed in a direction that cancels the main current of the main switch. It can be turned on with zero voltage and zero current.

  As a result, soft switching is performed at zero voltage and zero current when the main switch is turned on without using a reactor as in the conventional chopper circuit, thereby eliminating the heat loss and improving the conversion efficiency of the chopper circuit. In addition, overcurrent overvoltage can be prevented.

  According to the present invention, the auxiliary switch can regenerate the charge accumulated in the output diode to the DC power supply, thereby preventing overvoltage due to reverse recovery of the output diode.

It is a circuit diagram for demonstrating the example of a pressure | voltage rise type | mold structure of the chopper circuit of this invention. It is a diagram for explaining the disappearance of the output diode D ₅ of accumulated charge in the chopper circuit of the present invention. It is a figure for demonstrating the soft switching operation | movement in the chopper circuit of this invention. It is a figure which shows the voltage current of the main switch of the chopper circuit of this invention. It is a figure which shows the voltage current of the auxiliary switch of the chopper circuit of this invention. It is a figure which shows the voltage current of the output diode of the chopper circuit of this invention. It is an operation | movement diagram for demonstrating the operation example of the chopper circuit of this invention. It is a basic operation waveform diagram of each part for explaining an operation example of the chopper circuit of the present invention. It is a circuit diagram for demonstrating the 2nd example of a form of this invention. It is a circuit diagram for demonstrating the 3rd example of a form of this invention. It is a circuit diagram for demonstrating the 4th form example of this invention. It is a circuit diagram for demonstrating the 5th example of a form of this invention. It is a figure which shows the voltage-current characteristic of the main switch in the form using the coupling reactor of this invention. It is a figure which shows the voltage-current characteristic of the auxiliary switch with the form using the coupling reactor of this invention. It is a figure which shows the voltage-current characteristic of the output diode in the form using the coupling reactor of this invention. It is a figure which shows the whole waveform in the form using the coupling reactor of this invention. It is a circuit diagram for demonstrating the 6th form example of this invention. It is a figure which shows the hard switching operation | movement waveform of the 6th example of this invention. It is a figure which shows the soft switching operation | movement waveform of the 6th example of this invention. It is a figure which shows the circuit example which applied the chopper circuit of this invention to each type. It is a figure which shows the circuit example which applied the chopper circuit of this invention to the buck-boost type | mold. It is a circuit diagram for demonstrating the 7th example of a form of this invention. It is a circuit diagram for demonstrating the 8th example of this invention. It is a circuit diagram for demonstrating the 9th form example of this invention. It is a circuit diagram for demonstrating the 10th example of a form of this invention. It is a circuit diagram for demonstrating the 11th form example of this invention. It is a circuit diagram for demonstrating the 12th form example of this invention. It is a circuit diagram for demonstrating the 13th example of a form of this invention. It is a circuit diagram for demonstrating the 14th example of a form of this invention. It is a circuit diagram for demonstrating the conventional C bridge chopper circuit. It is a circuit diagram for demonstrating a QRAS chopper circuit. It is a circuit diagram for demonstrating the voltage current of the main switch of a QRAS chopper circuit. It is a circuit diagram for demonstrating the voltage of the output diode of a QRAS chopper circuit.

Explanation of symbols

E ₁ … DC power supply
S ₁ ... main switch
S ₂ ... Auxiliary switch
C ₁ ... Snubber capacitor
D ₁ Snubber diode
L ₁ , L ₂ ... main reactor
D ₅ … Output diode
C ₀ ... smoothing output capacitor 101 ... voltage (main switch S ₁ )
102 ... voltage (auxiliary switch S ₂₎
103 ... voltage (output diode D ₅₎
201 ... current (main switch S ₁ )
202 ... current (auxiliary switch S ₂₎
203 ... current (output diode D ₅₎
111 ... voltage (main switch S ₁₎
211 ... current (main switch S ₁₎
213 ... voltage (output diode D ₅₎

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  Hereinafter, an example of a boost type configuration of a chopper circuit according to the present invention will be described with reference to FIGS.

FIG. 1 is a circuit diagram for explaining a boost-type configuration example of a snubber-assisted ZVZCT (Snubber-Assisted Zero Voltage and Zero Current Transition chopper) chopper circuit according to the present invention. In the configuration example of FIG. 1, a main switch S ₁ , an auxiliary switch S ₂ , main reactors L ₁ and L ₂ , a snubber diode D ₁ and a snubber capacitor C ₁ , an output diode D ₃ and an output smoothing capacitor C ₀ are provided. Prepare.

The main reactors L ₁ and L ₂ are two reactors connected in series, but equivalently constitute one reactor and one end is connected to the high potential side terminal of the DC power supply E ₁ . The main switch S ₁ has one pole connected to the other end of the series connection of the main reactors L ₁ and L ₂ and the other pole connected directly to the low voltage terminal of the DC power supply E ₁ . Between the main switch S ₁ poles connects a series connection of the output diode D ₅ and the output smoothing capacitor C ₀ in parallel, the output smoothing capacitor C ₀ load is connected in parallel. Further, between both electrodes of the main switch S ₁ connects the series connection of the snubber diode D ₁ and the snubber capacitor C _1. The auxiliary switch S ₂ is connected between the connection point of the snubber diode D ₁ and the snubber capacitor C ₁ and the connection point of the series connection body of the _two main reactors L ₁ and L ₂ .

In the configuration of this chopper circuit, the above-described QRAS chopper circuit is the point where the diodes D ₃ and D ₄ are deleted, the auxiliary switch S ₂ is a reverse blocking IGBT, the point where the reactor SL ₁ is deleted, The difference is that switching is performed not only with zero current but also with zero current and zero voltage when the main switch is turned on. Auxiliary switch S ₂ as by using a reverse blocking type IGBT, it is possible to remove the regenerative diode D ₃ which was conventionally required.

The auxiliary switches S ₂ of the chopper circuit, since the turn-off operation is zero current switching, it is possible to remove the diode D ₄ for imparting a common snubber protection switching means S ₁ and the auxiliary switch S ₂ .

  The chopper circuit of the present invention can be extinguished by passing the accumulated charge of the output diode through a part of the main reactor via the auxiliary switch, thereby suppressing the reverse recovery current.

Figure 2 is a diagram for explaining the disappearance of accumulated charge of the output diode D ₅ in the chopper circuit of FIG. In FIG. 2, when the auxiliary switch S ₂ is turned on, the current I _R due to the charge accumulated in the output diode D ₅ flows through the main reactor L ₂ in the direction opposite to the direction of the main current of the main reactor. Therefore, current I _R decreases the energization current of main reactor L ₂ . Therefore, active power component? Pr = I _R ² · R ₂ which occurs in the main reactor L ₂ acts as reducing the loss due to the resistance component R ₂ in the main reactor L _2. Note that by turning on the auxiliary switch S ₂ before turning on the main switch S _1, regenerates the charge accumulated in the output diode D ₅ to the input side.

Therefore, according to the chopper circuit of the present invention, current I _R at the time of storing charge of the output diode D ₅ disappears becomes a direction to reduce the loss of the main reactor, which acts in a direction to increase the efficiency of the chopper circuit.

In conventional QRAS chopper circuit, because of the large reactor L _2, can not be eliminated the accumulated charge of the output diode D _5, upon turning off of the output diode, a large reverse recovery surge voltage due to the accumulated charges are generated. On the other hand, in the chopper circuit of the present invention, the stored charge annihilation current that acts in the direction of increasing the efficiency flows, so that the reverse recovery current suppression circuit is used, and no large reverse recovery surge voltage is generated by the output diode.

  In addition, the chopper circuit of the present invention can reduce the switching loss by using the regenerative resonance phenomenon to create a zero voltage zero current state and turning it on.

FIG. 3 is a diagram for explaining a soft switching operation in the chopper circuit of FIG. In the conventional QRAS chopper circuit, the reactor SL ₁ is used so that the current rises slowly when the main switch S ₁ is turned on. In contrast, the chopper circuit of the present invention, by forming a regenerative path by auxiliary switch S _2, and remove the reactor SL _1. This regenerative path uses the regenerative resonance phenomenon of the snubber capacitor C ₁ , thereby creating a state of zero voltage and zero current in the main switch S ₁ .

  As a result, the clamp voltage of the snubber capacitor, which greatly exceeds the power supply voltage generated at the time of turn-on, can be suppressed to a low voltage up to the power supply voltage. Therefore, the capacity of the snubber capacitor can be selected to be small according to the turn-on time of the main switch, the snubber regenerative power itself can be reduced, and the efficiency of the entire chopper circuit can be improved.

In the chopper circuit of the present invention, the snubber capacitor C ₁ is provided in order to make the main switch S ₁ turn-off soft, and the energy stored in the snubber capacitor C ₁ is used as an auxiliary when the main switch S ₁ is turned on. through switch S ₂ and the input side, antiparallel flowing the diode is set to zero the current flowing into the main switch S _1, both ends of the main switch S ₁ still by the discharge of the snubber capacitor C ₁ connected to the main switch S ₁ The voltage applied to is zero.

Further, in the chopper circuit of the present invention, the regenerative current Is, for regeneration in the direction of reducing the energization current of the main reactor L _2, active power component ΔPs = Is _² · R ² which is generated during regenerative action, main reactor L _This will reduce the loss of ₂ , and will increase the efficiency of the chopper circuit. R ₂ is the internal resistance of the main reactor L ₂ .

  As described above, the chopper circuit of the present invention functions as a reverse recovery current suppression circuit that extinguishes the accumulated charge of the output diode, and also functions as soft switching that eliminates the need for a regenerative reactor using regenerative resonance.

  In addition, the chopper circuit of the present invention has a configuration in which the main reactor is divided, so that the regenerative reactor is unnecessary, and the energy accumulated in the output diode and the snubber capacitor is not directly regenerated to the power supply side, By causing the main current of the main reactor to flow in a direction that cancels out, the power loss in the main reactor can be reduced.

The chopper circuit of the present invention can transfer the energy of the snubber capacitor directly to the main reactor without using an auxiliary regenerative capacitor. For example, even if the charging voltage of the snubber capacitor is charged higher than the output voltage due to the influence of the wiring reactor, the regenerative energy is transferred to the main reactor L ₂ in the input power direction, and the regenerative energy in the output direction is The main reactor L ₁ can be moved and regenerated. Therefore, it is possible to achieve higher efficiency than a method of using a reactor separately from the main reactor and regenerating via an auxiliary circuit path other than the main circuit.

Incidentally, FIG. 4 shows a voltage-current of the main switch S _1, FIG. 5 shows the voltage-current of the auxiliary switch S _2, FIG. 6 shows the voltage of the output diode D _5.

In the voltage-current characteristic of the main switch S ₁ shown in FIG. 4, the voltage 101 starts to drop at 49.939 sec and then becomes zero at 49.941 sec. On the other hand, since the current 201 is zero until 49.941 sec, zero voltage zero current is realized when the main switch S ₁ is turned on.

The voltage-current characteristic of the auxiliary switch S ₂ shown in FIG. 5, the voltage 102, the main switch S ₁ is turned on at a time prior to the on, current 202 is reduced to increase across the 49.940Sec. At the time of turn-off (around 49.960 sec in FIG. 5), a peak is observed in the voltage 102. This peak is generated in the simulation, but it has been confirmed that it does not occur in the actual measurement, and there is no problem.

The voltage characteristics of the output diode D ₅ shown in FIG. 6, the voltage 103 is conventionally peak voltage is eliminated by the main switch S ₁ of the reverse recovery current that occurs during turn-on.

  Next, an example of operation of the chopper circuit of the present invention will be described with reference to FIGS. FIG. 7 is an operation diagram, and FIG. 8 is a basic operation waveform diagram of each part.

In mode 1 (MODE1 7), and on the auxiliary switch S ₂ at the time of -t2, the main switch S ₁ is turned off, the output diode D ₅ modes carrier disappearance of starting. This moment, the auxiliary switch S ₂ is turned on from the current zero, it turns on the soft switching. During this time, the voltage of the snubber capacitor C ₁ maintains a substantially constant voltage not discharged. Current of the auxiliary switch S ₂ is increased, then disappearance carrier output diode D ₅ from the time it reaches the nearly load current, that turned off and reverse recovery, this mode is terminated.

In mode 2 (MODE2 7), at time of -t1, output diode D ₅ is turned off, the voltage V _c1 of the snubber capacitor C ₁ is directed to zero from a positive resonates sinusoidally.

Mode 3 In (MODE3 7), all the charges accumulated in the snubber capacitor C ₁ discharges, at time t0 the voltage V _c1 becomes zero voltage, the main switch S ₁ is turned on, the resonance regenerative current, to Tsuryu in the direction of canceling the main current of the main switch S _1. At this time, the main switch S ₁ is turned on from zero current. The regenerative energy stored in the main reactor L ₂ during the mode 1 and mode 2 is regenerated to the input power source via the auxiliary switch S ₂ while canceling the current of the main switch S ₁ as a negative current source. , Almost linearly decreasing to zero.

Mode 4 In (MODE4 in FIG. 7), at t1, becomes zero regenerative current of the main reactor L ₂ is reduced, the diode D ₁ is turned off, the main reactor L ₁ and L ₂ of the current through the main switch S ₁ Then go straight again to increase.

In mode 5 (MODE5 in FIG. 7), at t2, the main switch S ₁ and the auxiliary switch S ₂ are simultaneously turned off. At this time, the main switch S ₁ is turned off from zero voltage by the snubber capacitor C ₁ , and the auxiliary switch S ₂ is turned off by zero current, and both are turned off by soft switching. However, the present invention is not limited to simultaneous off. The auxiliary switch S ₂ may be turned off before the main switch S ₁ when the current changes.

In mode 6 (MODE 6 in FIG. 7), at t3, the output diode D ₅ is turned on, the main reactor L _1, the energy stored in L ₂ is supplied to the load. auxiliary switch S ₂ is turned on again at t4, the next cycle starts from the mode 1.

As described above, operate in soft switching in the main switch auxiliary switch both overcurrent by reverse recovery current of the output diode D _5, the overvoltage does not occur.

  Hereinafter, other embodiments of the chopper circuit of the present invention will be described with reference to FIGS.

FIG. 9 is a circuit diagram for explaining the second embodiment. Here, the embodiment shown in FIG. 1 is a first embodiment. The second embodiment, instead of the reverse blocking IGBT as auxiliary switch S _2, an example of using a series connection of normally of the antiparallel diode with IGBT and the diode D _3, as in the first embodiment Operate.

10 to 12 are circuit diagrams for explaining the third to fifth embodiments. The fourth to sixth embodiments are examples in which the main reactors L ₁ and L ₂ are integrally formed by a coupled reactor having a mutual inductance, and operate in substantially the same manner as the first embodiment.

In the form according to coupling inductance, when turning on the auxiliary switch S _2, by the action of mutual inductance, charge required for carrier disappearance of the output diode D ₅ to the main reactor L ₁ flows, correspondingly, the decrease in current is accelerated, auxiliary switch S ₂ and it is possible to reduce the time difference between the main switch S _1, as compared with the case binding is not, it is possible to reduce the resonance period.

13 shows the voltage / current characteristics of the main switch S ₁ in the form using the coupling reactor, FIG. 14 shows the voltage / current characteristics of the auxiliary switch S _{2 in} the form using the coupling reactor, and FIG. shows the voltage-current characteristic of the output diode D ₅ in the form using the reactor, also, FIG. 16 shows the entire waveform in the form using the coupling reactor.

In the voltage-current characteristics of the main switch S ₁ shown in FIG. 13, the time of turn-on of the main switch S _1, the current 201 is generated after the voltage 101 becomes substantially zero voltage, and in time of turn off, current 102 is substantially zero The voltage 202 rises in a state of current.

The voltage-current characteristic of the auxiliary switch S ₂ shown in FIG. 14, the auxiliary switch S ₂ is operating with a small time difference of slightly earlier timing than the main switch S _1. In the voltage-current characteristic of the output diode D ₅ shown in FIG. 15, the stored charge flows to the main reactor side when the auxiliary switch S ₂ is turned on, and shows the characteristics of the voltage 103 and the current 203. FIG. 15 also shows FIGS. 13 to 14.

  FIG. 17 is a circuit diagram for explaining the sixth embodiment. In each form mentioned above, it does not operate | move by soft switching over all load conditions, and it becomes a part hard switching depending on the mode. In this case, since current flows through the auxiliary circuit, the efficiency may be lower than that of conventional hard switching.

  Therefore, an auxiliary circuit for soft switching may be gate-blocked so that the zero voltage zero current operation is temporarily stopped only for a certain period, and hard switching using only the main switch is also used.

The circuit example shown in FIG. 17 is an example in which both hard switching and soft switching are used together, and an output clamp diode D ₆ is added to the snubber capacitor C ₁ . In this case, it changes between the hard switching operation waveform shown in FIG. 18 and the soft switching operation waveform shown in FIG. Note that hard switching in FIG. 18, the auxiliary switch S ₂ is performed by temporarily stopping, soft switching of FIG. 19 is performed by operating the auxiliary switch S _2.

Incidentally, FIG. 18 (a), the auxiliary switch S ₂ a shows the voltage 101 and current 102 of the main switch S ₁ in the case of stopping, FIG. 18 (b), aid in the case where the auxiliary switch S ₂ is stopped The voltage 201 and current 202 of the switch S ₂ are shown. Further, FIG. 19 (a), the auxiliary switch S ₂ a shows the voltage 101 and current 102 of the main switch S ₁ in the case of stopping, FIG. 18 (b), aid in the case of operating the auxiliary switch S ₂ The voltage 201 and current 202 of the switch S ₂ are shown.

  Besides the step-up type described above, the chopper circuit of the present invention can be applied to a step-down type, a step-up type, a step-up / step-down type, a CUK type, a SEPIC type, a ZETA type, and a step-up / step-down type.

  20 shows a step-down type (FIG. 20A), a step-up type (FIG. 20B), a step-up / step-down type (FIG. 20C), a CUK type (FIG. 20D), FIG. 21 shows a circuit example applied to the SEPIC type (FIG. 20E) and ZETA type (FIG. 20F), and FIG. 21 shows a circuit example applied to the step-up / step-down type.

The step-up / step-down circuit example shown in FIG. 21 is equivalent to the integration of the step-down type circuit shown in FIG. 20A and the step-up type circuit shown in FIG. _One pole of ₁ is connected to the high potential side terminal of the DC power supply E ₁ , _one pole of the other main switch S ₁ ′ is connected to the low potential side terminal of the DC power supply E ₁ , and both main switches S ₁ , a series connection of S ₁ 'the other formed by connecting pole two main switches S ₁ of, S _1', and connected between the two electrodes of each of the main switches S _1, S ₁ ', snubber diode D _1, D ₁ 'and two snubber capacitors C ₁ and C ₁ ' in series, one end connected to the connection point of the two main switches S ₁ and S ₁ ', and the other end connected to the DC power supply terminal to one in series connection of two main reactor which is divided into two constituting a reactor L _1, L _2, a connection point between a snubber diode D ₁ and the snubber capacitor C ₁ and Sri A vector L _1, auxiliary switch S ₂ connected between the connection point of the series connection of L _2, the series connection of the snubber diode D ₁ 'and the snubber capacitor C _1' and the connection point and the main reactor L _1, L ₂ And an auxiliary switch S ₂ ′ connected to the connection point of the body.

  In any of the circuit configurations described above, as in the first embodiment, two main reactors that are equally divided into two reactors and one pole are connected to one end of the series connection body of the main reactors. A main switch with the other pole connected directly to one voltage terminal of the DC power source, a series connection of a snubber diode and a snubber capacitor connected between both poles of the main switch, and a connection between the snubber diode and the snubber capacitor This point is common in that it includes an auxiliary switch connected between the point and the connection point of the series connection body of the two main reactors.

  Moreover, this invention can also be set as the form (seventh form-14th form) shown below.

In the seventh embodiment, as shown in FIG. 22, a very small snubber capacitor C ₁ is connected in parallel with the main switch S ₁ without providing a series connection body of a snubber capacitor and a snubber diode, and the regenerative reactor L _This is a configuration in which _x is provided separately, and the efficiency can be improved. Furthermore, since the capacitance of the snubber capacitor C ₁ may be very small, even in the mode in which the voltage remains, it can be operated.

In the eighth and ninth embodiments, as shown in FIGS. 23 and 24, the above-described snubber capacitor is deleted, and soft switching is performed using the stray capacitance of the main switch S ₁ instead. By utilizing the stray capacitance of the semiconductor device of the main switch S _1, it is possible to perform soft switching with only three elements of the two switching elements main reactor, efficiency can be enhanced. Note that the ninth embodiment shown in FIG. 24 is a configuration example in which the regenerative reactor L _x is separately provided.

In the tenth embodiment, as shown in FIG. 25, the conventional snubber diode is eliminated, and only the snubber capacitor C ₁ and the auxiliary switch S ₂ are used, thereby reducing the number of components and increasing the efficiency. it can. Also, the snubber capacitor C ₁ is also the main switch S ₁ is turned on from a state in which the charging voltage is left, it is possible to semiconductor devices of the main switch S ₁ is a very small capacitance so as not to damage.

As in the tenth embodiment, in the eleventh embodiment, as shown in FIG. 26, the conventional snubber diode is deleted, and a circuit having only the snubber capacitor C ₁ and the auxiliary switch S ₂ is provided. Can be reduced and efficiency can be increased.

In the eleventh embodiment, when the current in the main reactor L ₂ is turned off the auxiliary switch S ₂ while remaining, in order to prevent overvoltage, it is adding diode D _4.

In the tenth embodiment, by providing the minimum on time of the auxiliary switch S _2, it is possible to remove the diode D _4.

In the twelfth mode, as shown in FIG. 27, gate control for switching between soft switching and hard switching is performed. In the mode in which the voltage remains in the snubber capacitor C ₁ (boost rate is 2 or less), the auxiliary switch S ₂ and gate block performs hard switching by the main switch S _1, the efficiency is increased region (the step-up ratio is 2 or higher) performing the soft switching.

  In FIG. 27, 301 indicates the case of hard switching, and 302 indicates the case of using both hard switching and soft switching in the present invention.

  This soft switching and hard switching can be applied to the above-described embodiments.

In the thirteenth mode, as shown in FIG. 28, the main reactors L ₁ and L ₂ of the seventh to twelfth modes are arranged on the low potential side of the DC power supply. As shown in FIG. 29, in the fourteenth embodiment, the main reactors L ₁ and L ₂ are connected to the low potential side of the DC power supply in the configuration including the snubber diode D ₁ of the _first to sixteenth embodiments. It is a form arrange | positioned.

In the chopper circuit of the present invention, the wiring inductance of the minute are produced in the wiring portion of the high-potential side of the main switch S ₁ wiring portion and the low potential side, by these effects, some or higher than snubber capacitor output voltage Although high-frequency vibration may occur, the present invention operates effectively even with such a parasitic regeneration phenomenon.

  The following table compares the efficiency when the boost type is taken as an example.

  Further, in the chopper circuit of the present invention, soft switching is performed by turning on the auxiliary switch slightly earlier than the main switch, but turning on by turning on the auxiliary switch at the same time or after the main switch is performed. It is also possible to operate so as to perform only the regenerative operation without performing soft switching.

  The chopper circuit of the present invention may be configured by multiplexing the entire power supply system in addition to the main switch and auxiliary switch connected in series and parallel.

  Further, the main reactor of the chopper circuit of the present invention may have a split structure or an integral structure.

  In the chopper circuit of the present invention, the antiparallel diode of the main switch may be deleted when soft switching of zero voltage and zero current is not performed.

  Further, in the chopper circuit of the present invention, the input smoothing capacitor may be deleted when the input power supply has a current ripple absorption capability.

  The present invention is not limited to the embodiments described above. Various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

  In the chopper circuit of the present invention, the auxiliary switch is not limited to the reverse blocking IGBT. A series circuit of an IGBT having no reverse breakdown voltage with a diode or a series circuit of an IGBT with a diode and an antiparallel diode may be used.

  The chopper circuit of the present invention can be applied not only to a fuel cell vehicle but also to a field using a semiconductor power converter.

Claims (19)

Two main reactors that are divided into two, equivalently constituting one reactor,
A main switch in which one pole is connected to one end of the series connection body of the main reactor, and the other pole is directly connected to one voltage terminal of the DC power supply;
A series connection body of a snubber diode and a snubber capacitor connected between both poles of the main switch,
An auxiliary switch connected between the connection point of the snubber diode and the snubber capacitor and the connection point of the series connection body of the two main reactors,
The auxiliary switch has a snubber capacitor voltage of zero voltage so that the voltage of the main switch when turning on is zero voltage.   2. The chopper circuit according to claim 1, wherein the chopper circuit is any one of a step-down type, a step-up type, a step-up / step-down type, a CUK type, a SEPIC type, and a ZETA type. A series connection of two main reactors divided into two, equivalently constituting one reactor, one end of which is connected to the high potential side terminal of the DC power source;
A main switch in which one pole is connected to the other end of the series connection body of the main reactor, and the other pole is directly connected to a low voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
A series connection body of a snubber diode and a snubber capacitor connected between both poles of the main switch,
An auxiliary switch connected between the connection point of the snubber diode and the snubber capacitor and the connection point of the series connection body of the two main reactors,
The auxiliary switch has a snubber capacitor voltage of zero voltage so that the voltage of the main switch when turning on is zero voltage.   The auxiliary switch causes the electric charge accumulated in the output diode to flow through the main reactor on the DC power source side of the two main reactors in a direction opposite to the main current of the main reactor at the time of turn-on. The chopper circuit according to claim 3, wherein the chopper circuit is regenerated.   When the main switch is turned on, the regenerative resonance between the snubber capacitor and the main reactor connected to the DC power source side causes the charge accumulated in the snubber capacitor to be transferred to the main reactor on the DC power source side of the two main reactors. 4. The chopper circuit according to claim 3, wherein the chopper circuit is regenerated to the DC power source by flowing in a direction opposite to the main current of the main reactor.   6. The chopper according to claim 1, wherein the main switch is turned on from a zero voltage and zero current state by turning on the main switch after the auxiliary switch is turned on. circuit.   The chopper circuit according to any one of claims 1 to 6, wherein the main reactor is integrally formed by a coupled reactor having a mutual inductance.   The chopper circuit according to claim 3, further comprising an output clamp diode between the snubber capacitor and the output capacitor. A main reactor having one end connected to one terminal of a DC power supply;
A main switch having one pole connected to the other end of the main reactor and the other pole connected directly to the low voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
A capacitor connected between both poles of the main switch;
A chopper circuit comprising a series connection body of a regenerative reactor and an auxiliary switch connected between a high potential side of the capacitor and a high potential side terminal of a DC power source. A serially connected body of two divided main reactors, one end of which is connected to one terminal of a DC power source and equivalently constitutes one reactor;
A main switch in which one pole is connected to the other end of the series connection body of the main reactor, and the other pole is directly connected to a low voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
An auxiliary switch directly connected between a connection point between the main switch and the other end of the series connection body of the main reactor and a connection point of the series connection body of the two main reactors is provided. Chopper circuit. A main reactor having one end connected to one terminal of a DC power supply;
A main switch having one pole connected to the other end of the main reactor and the other pole connected directly to the low voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
A series connection body of a regenerative reactor and an auxiliary switch connected between a connection point between the main switch and the other end of the series connection body of the main reactor and a high potential side terminal of a DC power supply is provided. Chopper circuit. A serially connected body of two divided main reactors, one end of which is connected to one terminal of a DC power source and equivalently constitutes one reactor;
A main switch having one pole connected to the other end of the main reactor and the other pole connected directly to the low voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
A capacitor for directly connecting both poles of the main switch;
A chopper circuit comprising an auxiliary switch connected between a high potential side of the capacitor and a connection point of a series connection body of the two main reactors.   13. The chopper circuit according to claim 9, wherein the main switch is switched between hard switching and soft switching by gate control of the auxiliary switch. A serially connected body of two divided main reactors, one end of which is connected to one terminal of a DC power source and equivalently constitutes one reactor;
A main switch in which one pole is connected to the other end of the series connection body of the main reactor, and the other pole is directly connected to a low voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
A snubber capacitor between both poles of the main switch;
A chopper circuit comprising: an auxiliary switch that directly connects a connection point between the snubber capacitor and the high potential of the snubber capacitor and a connection point between the two main reactors in series.   15. The chopper circuit according to claim 9, wherein the main reactor is provided on a high potential side or a low potential side of a DC power source. A series connection of two main reactors divided into two, which equivalently constitutes one reactor, with one end connected to the low potential side terminal of the DC power supply;
A main switch in which one pole is directly connected to the other end of the series connection body of the main reactor, and the other pole is directly connected to a high voltage terminal of the DC power supply;
A series connection body of an output diode and an output smoothing capacitor connected between both poles of the main switch,
A series connection body of a snubber diode and a snubber capacitor connected between both poles of the main switch,
A chopper circuit, comprising: an auxiliary switch that directly connects a connection point between the snubber diode and the snubber capacitor and a connection point of the series connection body of the two main reactors. Connect one pole of one main switch to the high potential side terminal of the DC power supply, connect one pole of the other main switch to the low potential side terminal of the DC power supply, and connect the other pole of both main switches. A series connection of two main switches
Two series connection bodies of a snubber diode and a snubber capacitor connected in the forward direction from the high potential of the DC power source to the low potential between both poles of each main switch,
A series connection of two main reactors divided into two to constitute one reactor equivalently, one end connected to the connection point of the two main switches and the other end connected to a terminal of a DC power source;
A chopper circuit, comprising two auxiliary switches respectively connected between two connection points of the snubber diode and the snubber capacitor and a connection point of the series connection body of the two main reactors. A series connection of a snubber diode and a snubber capacitor is connected between the poles of the main switch, and one pole of the main switch is connected to a series connection of two main reactors or two inductances in series. One end and one pole of a diode, the other pole of the main switch is directly connected to one voltage terminal of a DC power supply, and a load is connected to the other pole of the output diode,
An auxiliary switch in which the snubber diode is connected between a connection point of a snubber capacitor and a connection point of a series connection body of the main reactor or a connection point of two inductances;
Before the main switch is turned on, the auxiliary switch is turned on by the soft switching by the main reactor, the stored charge is extinguished, and the reverse blocking characteristic of the diode is restored by the soft switching, so that the main operation is performed by the resonance operation of the snubber capacitor and the main reactor. Turn on the switch with soft switching,
The main switch is turned off by soft switching by the snubber capacitor,
The chopper circuit is characterized in that the auxiliary switch is turned off by soft switching at zero current.   2. The chopper circuit according to claim 1, wherein the auxiliary switch includes a series connection of an IGBT with an antiparallel diode and a diode.