JP2010115099A - Boost chopper circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the gradient of a switching current of a switch component gentle at the start of the current, to reduce the turn-on loss of the switch component and the loss of the reverse current characteristic of a diode, to make a zero voltage turned-off via the low loss snubber circuit at the turn-off of the switch component, and improve the efficiency of a boost chopper circuit. <P>SOLUTION: In order to make the zero-voltage turned off, the energy of a capacitor C2 is moved to a capacitor C3 by series resonance operation when a switch component Q1 is turned on and excess accumulative magnetic energy is absorbed by the capacitor C2 to discharge the capacitor C3 to a smoothing capacitor C1 and a load RL via a transformer T1 and a diode D5 when the switch component is turned off. In order to make the gradient of the switching current of the switch component gentle at the start thereof, the main coil 1A of a boost reactor L1 is provided with a coil 1B to accumulate magnetic energy while the switch component of a reactor L2 is turned off and to discharge magnetic energy while the switch component Q1 is turned on. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a chopper circuit that boosts a DC power supply and a boost type power factor correction circuit for improving the power factor, and more particularly to a boost chopper circuit that can improve efficiency.

A conventional boost chopper circuit is shown in FIG. In FIG. 12, one end of the step-up reactor L1 is connected to the positive side of the input power supply V1, the other end is connected to the anode side of the diode D1, and the high-voltage side terminal of the switch element Q1, and the cathode side of the diode D1 is smoothed. Connected to the positive side of the capacitor C1, the negative side of the input power source V1 and the negative side of the smoothing capacitor C1 are connected, the load RL is connected in parallel to the smoothing capacitor C1, and the low voltage side terminal of the switching element Q1 is connected to the negative side of the smoothing capacitor C1. In this configuration, a series circuit composed of a resistor R1 and a capacitor C2 is connected to both ends of the switch element Q1, and the oscillation control circuit 10 is connected to the control terminal of the switch element Q1.

FIG. 13 shows operation waveforms of FIG. At time t1 in FIG. 13, the switching element Q1 is turned on by the oscillation control circuit 10, and magnetic energy is accumulated in the boost reactor L1. Next, when the switching element Q1 is turned off by the oscillation control circuit 10, the magnetic energy of the step-up reactor L1 is released through the diode D1 to the smoothing capacitor C1 and the load RL while superimposing the input power supply V1. Thus, a predetermined voltage higher than that of the input power supply V1 is obtained.

When the switch element Q1 is turned off, a high surge voltage is generated across the switch element Q1 due to the influence of excess stored energy. At this time, the rising slope of VQ1 of the switching element Q1 is steep. In order to suppress this, in general, the series circuit of the resistor R1 and the capacitor C2 in FIG. 12 is connected in parallel to the switch element Q1. Thus, when the switch element Q1 is turned off, excess accumulated energy is charged to C2 through R1, so that the rising slope of VQ1 of the switch element Q1 becomes gentle, and a high surge voltage is suppressed. Next, when the switch element Q1 is turned on, the energy of C2 is discharged by the switch element Q1 while being limited by R1, and the zero voltage turn-off is performed, and the loss at the time of turn-off of the switch element Q1 is reduced.

  However, the conventional circuit has the following two problems. First, since the rising of the switching current IQ1 when the switch element Q1 is turned on is steep, a large switching loss and a reverse current loss of the diode D1 occur in the section t1 in FIG. The reverse current of the diode D1 is not shown in FIG.

Second, in a section between t1 and t2 in FIG. 13, a charge / discharge current IR1 flows to the capacitor C2 in the snubber circuit including the resistor R1 and the capacitor C2 when the switch element is turned off and on. Since this charging / discharging current IR1 also flows through the resistor R1, a large loss occurs. Further, among the charging / discharging current IR1, the discharge current flowing through the switch element Q1 has a steep rise, so that the loss of the switch element Q1 in the section t1 in FIG. 13 further increases. Further, if the value of the resistor R1 is increased in order to reduce the loss of the switching element Q1 at time t1, the capacitor C2 cannot be completely discharged and the zero voltage is not turned off, and the loss at the time of turning off the switching element Q1 increases. The above two problems become more excessive as the oscillation frequency increases.

As a first solution for smoothing the rising slope of the switching current of the switching element, which is the first problem, in a conventional boost chopper circuit, a winding winding magnetically coupled to the main winding of the boost reactor A wire is provided and connected to the positive side of the smoothing capacitor through a second diode from the connection point of the main winding and the winding winding, and another terminal of the winding winding of the boost reactor and the high voltage of the switch element A series circuit composed of the first diode and the first reactor was connected to the positive electrode side of the smoothing capacitor from the connection point of the side terminal.

As a second solution to the first problem, in a conventional boost chopper circuit, a first reactor is connected between a positive electrode side of the input power source and the boost reactor, and the main winding of the boost reactor A winding winding magnetically coupled to the winding, and a high-voltage side terminal of the switch element is connected to a connection point between the main winding and the winding winding, and a positive electrode side of the smoothing capacitor is connected from the connection point via a second diode. And connected to the positive electrode side of the smoothing capacitor via the first diode from another terminal of the winding winding of the step-up reactor.

As a first solution for zero voltage turn-off, which is the second problem, in the conventional boost chopper circuit, the anode side of the third diode is connected to the high voltage side terminal of the switch element, and the cathode side is connected. Connect to one end of the first capacitor, connect the other end of the first capacitor to the low voltage side terminal of the switch element or the positive side of the smoothing capacitor, and connect the third diode to the first capacitor The anode side of the fourth diode is connected to the point, the cathode side and the second capacitor are connected, and one end of the primary winding of the transformer provided with the primary winding and the secondary winding is connected to the second capacitor. The other end of the primary winding of the transformer is connected to the high-voltage side terminal of the switch element, and 2 points of the transformer are connected from the connection point of the fourth diode and the second capacitor. A series circuit composed of a winding and a fifth diode is connected to the cathode side of the first diode, the polarity of the connection point between the second capacitor and the primary winding of the transformer, the second capacitor and the transformer The polarity of the connection point of the secondary winding was connected in the direction of the same polarity.

As a second solution of the second problem, the primary winding of the transformer is replaced with a second reactor from the first solution of the second problem. It replaced with the 3rd reactor and it connected to the positive electrode side of the smoothing capacitor through the 6th diode from the connection point of the 2nd reactor and the said 2nd capacitor | condenser.

As a third solving means for the second problem, the third reactor is changed to wiring from the second solving means for the second problem.

As a fourth solution to the second problem, the anode side of the third diode is connected to the high-voltage side terminal of the switch element, the cathode side and one end of the first capacitor are connected, and the first capacitor Is connected to the positive side of the smoothing capacitor, the anode side of the fourth diode is connected to the connection point of the first capacitor and the third diode, the cathode side and the second reactor are connected, The other end of the second reactor is connected to one end of the second capacitor, the other end is connected to the high-voltage side terminal of the switch element, and the fifth capacitor It connected to the positive electrode side of the smoothing capacitor via a diode.

A step-up chopper circuit in which the means for solving the first problem and the means for solving the second problem are combined.

According to the present invention, with the boost chopper circuit configuration as described above, when the switch element is turned on, the rising slope of the switching current of the switch element becomes gentle, and the turn-on loss of the switch element and the reverse current of the diode Characteristic loss is reduced. Subsequently, when the switch element is turned off, a low-loss snubber circuit absorbs the excess stored energy of the reactor, and the zero turn-off voltage is released to the smoothing capacitor and the load without increasing the turn-on loss of the switch element. , Loss is reduced. Since the rising slope of the switching current and the turn-off voltage of the switch element becomes gentle, an effect of reducing electromagnetic noise can be expected. Furthermore, the present invention may be applied to a boost type power factor correction circuit.

“First Embodiment”

A first embodiment of the present invention is shown in FIG. FIG. 1 shows a configuration example in claims 1 and 3. In the configuration of claim 1, a series circuit composed of a step-up reactor L1, a diode D1, and a reactor L2 each including a magnetically coupled main winding 1A and a winding winding 1B is connected to the positive electrode side of the input power source V1. Was connected to the positive electrode side of the smoothing capacitor C1. The black button of the boost reactor L1 in FIG. 1 indicates the polarity of the winding. Here, the reactor L2 has an inductance value of 1/10 times or less that of the boost reactor L1.

A load RL is connected in parallel to the smoothing capacitor C1, and the negative electrode side of the smoothing capacitor C1 and the negative electrode side of the input power supply V1 are connected. A switching element Q1 was connected between one end of the winding 1B of the step-up reactor L1 and the negative electrode side of the smoothing capacitor C1. The oscillation control circuit 10 is connected to the control terminal of the switch element Q1.

A connection point between the main winding 1A and the winding winding 1B of the boost reactor L1 is connected to the positive electrode side of the smoothing capacitor C1 through the diode D2.

Next, as a configuration of the low loss snubber circuit of claim 3, the anode side of the diode D3 is connected to the high voltage side terminal of the switch element Q1, the cathode side is connected to one end of the capacitor C2, and the other end is connected to the switch element. Connected to the low voltage side terminal of Q1. The capacitor C2 may be connected to the positive side of the smoothing capacitor C1 instead of the low voltage side terminal of the switching element Q1.

One end of the capacitor C3 is connected from the connection point of the capacitor C2 and the diode D3 via the diode D4. The other end of the capacitor C3 is connected to the primary winding 1P of the transformer T1 having the primary winding 1P and the secondary winding 1S, and the other end of the primary winding 1P is switched. Connect to the high voltage side terminal of the element Q1.

One end of a series circuit composed of the secondary winding 1S of the transformer T1 and the diode D5 is connected to the connection point between the capacitor C3 and the diode D4, and the other end is connected to the cathode side of the diode D1.

1 indicates the polarity of the winding, and the primary winding 1P and the secondary winding 1S of the transformer T1 are connected with the capacitor C3 interposed therebetween in the direction of the same polarity. The positions of the diode D1 and the reactor L2 may be reversed.

Next, operation waveforms of the first embodiment of the present invention are shown in FIG. The operation will be described with reference to FIG. When the switch element Q1 is turned off at the time t1 at the time t1 to t2, the release of the magnetic energy accumulated from the boost reactor L1 starts, and the capacitor C2 is charged via the diode D3, and the rising slope of VQ1 of the switch element Q1 It becomes gentle. The charging of the capacitor C2 ends at time t2. Further, the voltage VC3 across the capacitor C3 is charged in such a direction that the diode D4 side is the positive side when the switch element Q1 is on. At time t1, the flyback voltage of the boost reactor L1 is applied to the negative side of the capacitor C3, and the positive side of the capacitor C3 is the primary winding 1P, the secondary winding 1S, the diode D5, and the reactor L2 of the transformer T1. As a result, the energy of the capacitor C3 is discharged to the smoothing capacitor C1 and the load RL. The discharge current waveforms at this time are IT1P and IT1S in FIG. FIG. 2 shows a waveform when the number of turns of the primary winding 1P and the secondary winding 1S of the transformer T1 is equal.

When the charging of the capacitor C2 ends at time t2, normally, since the flyback voltage of the winding 1B of the boost reactor L1 is higher than that of the main winding 1A, the emission current ID2 flows through the diode D2. Absent. However, by connecting the reactor L2 in series with the diode D1, the emission current ID1 of the diode D1 has a gentle rising slope as shown in FIG. 2 due to the impedance of the reactor L2. A part passes through the primary winding 1P of the transformer T1 and flows as IT1S. When the voltage VC3 of the capacitor C3 becomes zero at time t3, IT1S also becomes zero. As described above, the portion of the emission current that should flow from the diode D1 flows through the diode D2. Since the discharge current ID2 flows from the main winding 1A and is magnetically coupled to the voltage VQ1 across the switching element Q1 between the times t2 and t4, the voltage of the winding 1B is superimposed on the output voltage Vo. It becomes the value. If the main winding 1A and the winding winding 1B are not magnetically coupled, a large surge voltage is generated at VQ1 of the switch element Q1.

In the transformer T1 during the discharging operation of the capacitor C3, a current flows from a direction where the black winding of the primary winding 1P in FIG. 1 is not present. At this time, in the secondary winding 1S, the diode D5 side without the black dot becomes the positive electrode, and current flows in the direction of the diode D5, so that the transformer is turned on and off, and only the magnetic energy is transmitted, and there is no storage capability. For this reason, the capacitor C3 is rapidly discharged.

On the other hand, during the charging operation of the capacitor C3, a charging current flows from the black button side to the switch element Q1 through the primary winding 1P of the transformer T1. At this time, the black winding side of the secondary winding 1S is the positive side, but no current flows through the secondary winding due to the diode D5. This is an ON / OFF operation of the transformer and has a magnetic energy storage capability, so that the charging current has a gentle rising waveform.

At time t4, the emission current ID1 of the diode D1 becomes a predetermined value, and the emission current ID2 of the diode D2 becomes zero. At this time, since only the diode D1 is turned on, the potential on the switch element Q1 side of the winding 1B of the boost reactor L1 is substantially reduced to the output voltage Vo, and the VQ1 of the switch element Q1 has a similar waveform. Further, since the voltage VC2 across the capacitor C2 is charged with substantially the same value as VQ1 of the switch element Q1, a slight current IT1P starts to flow from the primary winding 1P of the transformer T1.

At time t5, the switch element Q1 is turned on. At this time, the magnetic energy of the reactor L2 accumulated between the time t3 and the time t5 is discharged through the path of the diode D1 → the smoothing capacitor C1 and the load RL → the input power source → the boost reactor L1 → the reactor L2 during the time t5 to t6. Is done. As a result, the switching current IQ1 of the switching element Q1 does not flow by the amount corresponding to the emission current of the reactor L2, and the rising slope of Q1 becomes gentle as shown in FIG.
At the same time, the energy of the capacitor C2 is discharged while transferring to the capacitor C3. IT1P indicating this discharge current becomes a series resonance operation by the combined capacitance composed of the capacitor C2 and the capacitor C3 and the primary winding 1P of the transformer T1, and ends at time t7. The IT1P does not affect the rising slope of the switching current IQ1 by having a resonance waveform. From time t7 to t1, similarly to the conventional step-up chopper circuit, the switch element Q1 is in the on state, and magnetic energy is stored in the step-up reactor L1. By repeating the above operation, the rising slope of the switching current IQ1 becomes gentle when the switch element Q1 is turned on, and zero voltage is turned off when the switch element Q1 is turned off.
“Second Embodiment”

A second embodiment of the present invention is shown in FIG. The circuit configuration of FIG. 3 is the circuit configuration according to claims 2 and 3.

As a circuit configuration showing the second aspect, the main winding of the step-up reactor L1 having one end of the reactor L2 connected to the positive electrode side of the input power source V1 and the other end magnetically coupled to the main winding 1A and the winding winding 1B. Connected to one end of the wire 1A, and connected from one end of the winding 1B to the positive side of the smoothing capacitor C1 via the diode D1. The black button of the boost reactor L1 in FIG. 3 indicates the polarity of the winding. Here, the reactor L2 has an inductance value of ½ times or more that of the boost reactor L1. The combined inductance value of boost reactor L1 and reactor L2 is approximately the same as the inductance value of boost reactor L1 of the conventional boost chopper circuit of FIG. For this reason, the loss of the reactor is dispersed, and the temperature rise can be reduced.

A connection point between the main winding 1A and the winding winding 1B of the boost reactor L1 is connected to the positive electrode side of the smoothing capacitor C1 through the diode D2. A load RL is connected in parallel to the smoothing capacitor C1, and the negative electrode side of the smoothing capacitor C1 and the negative electrode side of the input power supply V1 are connected.

A switching element Q1 is connected between the connection point of the main winding 1A and the winding winding 1B of the boost reactor L1 and the negative side of the smoothing capacitor C1. The oscillation control circuit 10 is connected to the control terminal of the switch element Q1. The configuration of the low loss snubber circuit of claim 3 is the same as that of the first embodiment.

Next, operation waveforms of the second embodiment of the present invention are shown in FIG. Differences from the first embodiment will be described with reference to FIG. From time t1 to time t2 in FIG. 4, the IT1S of the secondary winding 1S of the transformer T1 is different. This is because in the first embodiment, the reactor L2 is inserted between the secondary winding 1S of the transformer T1 and the smoothing capacitor C1. During time t1 to t2, the capacitor C3 is discharged and VC3 becomes zero. At the same time, the capacitor C2 is charged, and the rising slope of the voltage VQ1 across the switch element Q1 becomes gentle.

At time t2 in FIG. 4, emission currents ID1 and ID2 begin to flow through the diodes D1 and D2. Normally, since the flyback voltage of the winding 1B is higher than the main winding 1A of the boost reactor L1, the emission current ID2 does not flow through the diode D2. However, since there is the reactor L2, the rising slope of the emission current from 1B of the step-up reactor L1 becomes gentle, and the portion that does not flow to the diode D1 flows to the diode D2 as the emission current ID2. When the emission current ID1 from the diode D1 reaches a predetermined value, the emission current from the diode D2 becomes zero. At this time, the voltage VQ1 across the switch element Q1 is different from the first embodiment, the high-voltage side terminal of the switch element Q1 is connected to the negative side of the winding 1B, and the positive side is the output voltage Vo. Since the potentials are substantially the same, the voltage drops by the voltage of the winding 1B, and VQ1 becomes lower than the output voltage Vo.

At time t4 in FIG. 4, the switch element Q1 is turned on, and at the same time, the polarity of the reactor L2 is reversed. Release of the magnetic energy of the reactor L2 accumulated by the winding 1B from time t2 to t4 starts. Since the emission current during the period from the time t4 to the time t5 does not flow to the switch element Q1, the rising slope of the switching current IQ1 becomes gentle. The operation of the low-loss snubber circuit according to claim 3 is the same as that of the first embodiment. As described above, the rising gradient of the switching current IQ1 of the switch element Q1 becomes gentle. Further, the rising slope of the voltage VQ1 across the switch element Q1 becomes gentle, and the zero voltage is turned off.
“Third Embodiment”

FIG. 5 shows a third embodiment of the present invention, and FIG. FIG. 5 shows the configuration of the low loss snubber circuit according to claims 2 and 4.

In the configuration showing the fourth aspect, the primary winding 1P of the transformer T1 in the second embodiment is changed to the reactor L3, the secondary winding 1S is changed to the reactor L4, and the connection point between the reactor L3 and the capacitor C3. To the positive electrode side of the smoothing capacitor C1 through the diode D6. The configuration showing claim 2 is the same as that of the second embodiment. FIG. 5 shows a case where the potential difference between the input voltage V1 and the output voltage Vo is relatively large and the ON ratio of the switch element Q1 is large.

The major difference from the second embodiment is that the low loss snubber circuit of claim 3 is changed to the low loss snubber circuit of claim 4, and the timing at which VC3 of the capacitor C3 is charged as shown in FIG. However, it is behind VC3 shown in FIG. 2 and VC3 shown in FIG. Further, the discharge end time of the capacitor C2 at time t5 in FIG. 6 is also delayed.

When the switch element Q1 is turned off from time t1 to time t2 in FIG. 6, the release of magnetic energy accumulated in the step-up reactor L1 and the reactor L2 and the parasitic inductance of the wiring starts, and the capacitor C2 is charged via the diode D3. Therefore, the rising slope of VQ1 of the switch element Q1 becomes gentle.

At times t2 to t3 in FIG. 6, during the ON period of the switch element Q1, the capacitor C3 that is charged in a direction in which the diode D4 side is positive is connected to the reactor L3 and the reactor L4 by the flyback voltage of the boost reactor L1. And passes through the diode D5 and is discharged to the smoothing capacitor C1 and the load RL while being clamped by the output voltage Vo. This discharge current is indicated by IL3 in FIG. This IL3 is a series resonance operation of the reactor L3, the reactor L4, and the capacitor C3 in the section from the time t2 to the time t3.

At time t5 in FIG. 6, the discharge current of the capacitor C2 is IL3 and flows to the switch element Q1. However, in reactor L3, magnetic energy is accumulated because IL3 flows from boost reactor L1 in the direction of smoothing capacitor C1 during the period from time t2 to t5. As a result, IL3 flowing to the switch element Q1 and the discharge current of the stored energy of the reactor L3 cancel each other, and the discharge end time of the capacitor C2 is delayed compared to the first and second embodiments.

The operation for smoothening the rising slope of the switching current IQ1 of the switch element Q1 is the same as in the second embodiment.

Here, the effect of the diode D6 in FIG. 5 will be described. A comparative waveform is shown in FIG. The operation waveform of FIG. 5 is shown in FIG. A case where there is no diode D6 is shown in FIG. The capacitor C3 from time t2 to t3 is discharged by the series resonance operation. This resonance current IL3 becomes maximum at time t3. The voltage across the capacitor C3 has a phase difference of 90 degrees and is zero volts. When the voltage reaches zero volts, the diode D6 is turned on and the resonance operation is not performed. At this time, when the diode D6 is not present, the resonance operation continues, the arcing due to the oscillation operation of the resonance occurs, and at the time t4 when the switch element Q1 is turned on, the capacitor C3 again has a direction in which the diode D4 side becomes the positive side. In other words, the energy of the capacitor C2 cannot be transferred to the capacitor C3. In this state, zero voltage turn-off is no longer possible. A diode D6 was inserted in order to prevent arcing due to the above-described resonant vibration operation.
“Fourth Embodiment”

A fourth embodiment is shown in FIG. FIG. 8 shows a configuration according to claim 2 and claim 5 in which the reactor L4 in the third embodiment is deleted. The operation is the same as that of the third embodiment, but since there is no reactor L4, the discharge end time of the capacitor C2 is delayed from that of the third embodiment. Therefore, this is applied when the potential difference between the input voltage V1 and the output voltage Vo is larger than that in the third embodiment.

Here, the effect of the reactor L4 will be described with reference to FIG. Operation Waveform with Reactor L4 From time t2 to t3 in FIG. 7A, IL3 indicating the discharge current of the capacitor C3 becomes maximum. Since IL3 also flows to reactor L4 at the same time, energy is accumulated. When the diode D6 is turned on, the reactor L4 starts to release stored energy. This energy release becomes a path of reactor L4 → diode D5 → smoothing capacitor C1 → capacitor C2 → diode D4 → reactor L4, and discharges a part of the energy of the capacitor C2.

On the other hand, when there is no reactor L4, ID5 of the diode D5 becomes zero ampere simultaneously with the turning on of the diode D6 at time t3, and does not discharge the capacitor C2. As described above, the effect of the reactor L4 increases the discharge end time of the capacitor C2. As described above, the fourth embodiment is suitable when the difference between the input voltage V1 and the output voltage Vo is larger than that of the third embodiment.
“Fifth Embodiment”

FIG. 9 shows the fifth embodiment, and FIG. 10 shows the operation waveforms. FIG. 9 shows a circuit configuration of the low loss snubber circuit according to claims 1 and 6. The circuit configuration showing claim 1 is the same as that of the first embodiment. The connection position of the diode D1 and the reactor L2 may be switched.

In the circuit configuration shown in claim 6, the anode side of the diode D3 is connected to the high voltage side terminal of the switch element Q1, the cathode side is connected to one end of the capacitor C2, and the other end is connected to the positive side of the smoothing capacitor C1. ing. The anode side of the diode D4 is connected to the connection point between the diode D3 and the capacitor C2, and the cathode side is connected to one end of the reactor L3.

One end of the capacitor C3 is connected to another end of the reactor L3, and the other end is connected to the high-voltage side terminal of the switch element Q1. The connection point between the capacitor C3 and the reactor L3 is connected to the cathode side of the diode D1 via the diode D5.

The operating principle for smoothening the rising gradient of the switching current IQ1 of the switch element Q1 is the same as in the first embodiment. At time t4 in FIG. 10, the capacitor C2 and the capacitor C3 are charged from the output voltage Vo, and IL3 starts to flow through the switch element Q1. IL3 at this time has a series resonance waveform of the combined capacitance composed of the capacitor C2 and the capacitor C3 and the reactor L3, and thus does not affect the rising slope of the switching current IQ1 of the switch element Q1. At time t6, the capacitor C2 is charged in a direction in which the positive electrode side of the smoothing capacitor C1 is positive. Capacitor C3 is charged in a direction in which reactor L3 is positive.

When the switching element Q1 is turned off at time t1, the flyback voltage of the boost reactor L1 is applied from the negative side of the capacitors C3 and C2.
For this reason, the capacitor C2 is clamped at the output voltage Vo to the smoothing capacitor C1 and the load RL via the diode D3, and rapidly discharged. This absorbs excess magnetic energy accumulated during the ON period of the switch element Q1. The capacitor C3 is clamped at the output voltage Vo to the smoothing capacitor C1 and the load RL via the diode D5, and is rapidly discharged. This discharge current waveform is ID5 shown in FIG. Further, the reactor L3 releases the magnetic energy accumulated in the section from time t4 to t6 to the smoothing capacitor C1 via the diode D5. Thus, charging / discharging of the capacitor C2 and the capacitor C3 is completed in one cycle of the switch element Q1, and the zero voltage is turned off.
“Sixth Embodiment”

A sixth embodiment of the present invention is shown in FIG. FIG. 11 shows a case where the input power supply of the first embodiment is changed to another method and used as a power factor correction circuit. The operation principle is the same as in the first embodiment.

The present invention relates to a switching power supply device including a step-up chopper circuit.

Circuit showing a first embodiment according to claim 1 and claim 3 of the present invention Operation waveform of the first embodiment Circuit showing a second embodiment according to claim 2 and claim 3 of the present invention Operation waveform of the second embodiment Circuit showing a third embodiment according to claim 2 and claim 4 of the present invention Operation waveform of the third embodiment Operation waveform of the third embodiment Operation waveform when diode D6 in the third embodiment is deleted Operation waveform when reactor L4 in the third embodiment is deleted Circuit showing a fourth embodiment according to claim 2 and claim 5 of the present invention Circuit showing a fifth embodiment according to claims 1 and 6 of the present invention Operation waveform of the fifth embodiment The circuit which shows 6th Embodiment by another input power supply system of this invention Conventional boost chopper circuit diagram Operation explanatory diagram of conventional boost chopper circuit

Explanation of symbols

VAC: AC power supply V1: Input power supply Vo: Output voltage DS1: Bridge diode L1: Boost reactor 1A: Main winding 1B of L1: Winding windings L2, L3, L4 of L1: First, second, and third reactors Q1: switch element 10: oscillation control circuit C1: smoothing capacitors C2, C3: first and second capacitors D1, D2, D3: first, second and third diodes D4, D5, D6: fourth and fourth 5, sixth diode RL: load R1: resistor T1: transformer 1P: primary winding 1S of T1: secondary winding IR1 of T1: current ID1, ID2 flowing through resistor R1, first diode D1, second Currents ID4 and ID5 flowing in the diode D2 of the current: current ID6 flowing in the fourth diode D4 and the fifth diode D5: current VQ1 flowing in the sixth diode D6: Voltage IQ1 across switch element Q1: Switching current VC2 and VC3 of switch element Q1: Voltage across terminal IT1P of first capacitor C2 and second capacitor C3: Current IT1S flowing through the primary winding of transformer T1: Transformer T1 Current IL1 flowing through the secondary winding: Current IL2 flowing through the step-up reactor L1: Current IL3 flowing through the first reactor L2: Current IL4 flowing through the second reactor L3: Current flowing through the third reactor L4

Claims (6)

In a step-up chopper circuit, comprising an input power source, a step-up reactor, a switch element, a first diode, a smoothing capacitor, and an oscillation control circuit connected to the control terminal of the switch element, magnetic coupling to the main winding of the step-up reactor The wound winding is provided, and is connected to the positive electrode side of the smoothing capacitor through a second diode from a connection point between the main winding and the winding winding. By connecting a series circuit composed of a first diode and a first reactor from a connection point between another terminal of the winding winding of the step-up reactor and the high-voltage side terminal of the switch element to the positive side of the smoothing capacitor, A step-up chopper circuit characterized by smoothing a rising slope of a switching current when the switch element is turned on to reduce loss of the switch element and reverse current characteristic loss of the first and second diodes. In a step-up chopper circuit comprising an input power source, a step-up reactor, a switch element, a first diode, a smoothing capacitor, and an oscillation control circuit connected to a control terminal of the switch element, the positive side of the input power source and the step-up reactor The first reactor is connected between the two. A winding coil magnetically coupled to the main winding of the step-up reactor is provided, a high-voltage side terminal of the switch element is connected to a connection point between the main winding and the winding winding, and a second diode is connected from the connection point. Connected to the positive electrode side of the smoothing capacitor. By connecting the other end of the winding winding of the step-up reactor via the first diode to the positive side of the smoothing capacitor, the rising slope of the switching current when the switch element is turned on is made smooth. And a reverse current characteristic loss of the first and second diodes. 3. A step-up chopper circuit comprising an input power source, a step-up reactor, a switch element, a first diode, a smoothing capacitor, and an oscillation control circuit connected to a control terminal of the switch element, and the step-up chopper circuit according to claim 1 and claim 2. In addition, the anode side of the third diode is connected to the high voltage side terminal of the switch element, the cathode side is connected to one end of the first capacitor, and the other end of the first capacitor is connected to the low voltage of the switch element. Connect to the side terminal or the positive side of the smoothing capacitor, connect the anode side of the fourth diode to the connection point of the third diode and the first capacitor, and connect the cathode side to one end of the second capacitor To do. One end of the primary winding of the transformer provided with the primary winding and the secondary winding is connected to another end of the second capacitor, and the other end of the primary winding of the transformer is connected to the switch element. Connected between the high voltage terminal and the anode side of the first diode. A series circuit including a secondary winding of the transformer and a fifth diode is connected to a cathode side of the first diode from a connection point between the fourth diode and the second capacitor. The polarity of the connection point of the second capacitor and the primary winding of the transformer and the polarity of the connection point of the second capacitor and the secondary winding of the transformer are connected in the same polarity. A step-up chopper circuit comprising the low-loss snubber circuit as described above. 4. The step-up chopper circuit according to claim 3, wherein the primary winding of the transformer is replaced with a second reactor, the secondary winding is replaced with a third reactor, and the connection point between the second reactor and the second capacitor is determined. A step-up chopper circuit comprising a low-loss snubber circuit connected to a positive electrode side of a smoothing capacitor via a sixth diode. 3. A step-up chopper circuit comprising an input power source, a step-up reactor, a switch element, a first diode, a smoothing capacitor, and an oscillation control circuit connected to a control terminal of the switch element. A step-up chopper circuit comprising a low-loss snubber circuit in which the third reactor of the four low-loss snubber circuits is replaced with a wiring. 3. A step-up chopper circuit comprising an input power source, a step-up reactor, a switch element, a first diode, a smoothing capacitor, and an oscillation control circuit connected to a control terminal of the switch element, and the step-up chopper circuit according to claim 1 and claim 2. , The anode side of the third diode is connected to the high-voltage side terminal of the switch element, the cathode side and the first capacitor are connected, and the other end of the first capacitor is connected to the positive side of the smoothing capacitor. The anode side of the fourth diode is connected to the connection point of the first capacitor and the third diode, and one end of the second reactor is connected to the cathode side. Another end of the second reactor is connected to one end of the second capacitor, and another end of the second capacitor is connected between the high-voltage side terminal of the switch element and the anode side of the first diode. To do. A connection point between the second capacitor and the second reactor is connected to the cathode side of the first diode through a fifth diode. A step-up chopper circuit comprising the low-loss snubber circuit as described above.

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