JP5548569B2 - DC power supply - Google Patents

Description

  The present invention relates to a DC power supply device that outputs DC power, and more particularly to a power supply device to which a semiconductor switching loss reduction circuit is added.

  A DC-DC converter is used when stabilizing an unstable DC power supply, changing a DC voltage, or outputting a DC power supply that is electrically insulated from the input. Among them, in a DC power supply device in which the input and output are electrically isolated, the transformer used for insulation can be reduced in proportion to the increase in the frequency used, but it occurs in the switching transient state of the semiconductor switch. Switching loss hinders semiconductor cooling, and there is a limit to the increase in switching frequency. For this purpose, Patent Documents 1 to 2 and Non-Patent Document 1 describe configurations of conventional examples in which switching loss is reduced by providing a commutation circuit using a resonance circuit.

  FIG. 2 shows an example of a resonance circuit described in these. Reference numeral 101 denotes a DC power source, 102 denotes a filter circuit including a filter reactor and a filter capacitor, 103 denotes a resonance circuit, and 104 denotes a gate control device that controls ON / OFF of each semiconductor switch.

  The circuit operation of FIG. 2 will be described. Q1 to Q4 are semiconductor switches constituting an inverter circuit, and free wheel diodes D1 to D4 are attached to the respective semiconductor switches. The primary winding of the transformer T is connected between a connection point a between the semiconductor switches Q1 and Q2 and a connection point b between the semiconductor switches Q3 and Q4, and the secondary winding is connected to the rectifier diodes D5 to D5 via the resonance reactor Lz. It is connected to the connection points c and d of the bridge consisting of D8. The output of this bridge is given to the load RL via the filter circuit 102.

  The resonance circuit 103 is inserted between the output side of the rectification bridge and the filter circuit 102.

  The gate control device 104 gives on / off commands to Q1 to Q4 and Qz. As the semiconductor switch, a bipolar transistor, a MOSFET, a thyristor, a gate turn-off thyristor, an IGBT, and the like can be considered. Here, an IGBT will be described as a representative example.

  FIG. 3 shows the time change of the operation waveform for explaining the known example of FIG. Iab is a current flowing between the points a and b, Vab is a voltage between the points a and b, Iz is a current flowing through the resonance circuit 103, and Vz is a voltage across the resonance capacitor Cz. Io indicates a current circulating from the rectifier bridge in the filter circuit 102 and the load RL.

  The circuit operation will be described with reference to the above. It is assumed that the gate control device 104 gives ON signals to Q1 and Q4, and the semiconductor switches Q1 and Q4 of the inverter circuit are in a conductive state. A current Iab flows and energy is transmitted from the DC power supply 101 to the load RL.

  When a signal for turning on the semiconductor switch Qz of the resonance circuit 103 is supplied from the gate control device 104 at time t0 before turning off the semiconductor switches Q1 and Q4 of the inverter circuit, the charging current of the resonance capacitor Cz flows from the DC power supply 101. . This current Iz is a series resonance current of the resonance reactor Lz and the resonance capacitor Cz. The current flowing in the semiconductor switches Q1 and Q4 is the sum of the current Id flowing on the load side and the resonance current Iz, and increases in a sine wave shape. At that time, a voltage is generated in the resonant capacitor Cz, which is higher than the secondary voltage of the transformer.

  At time t1, the charging is completed and the voltage reaches the maximum value. Thereafter, discharge of the resonance capacitor Cz starts, and a discharge current starts to flow through the path of the free wheel diode D9 and the resonance capacitor Cz. Here, if the turns ratio of the transformer T is 1: 1, the current Id of the filter reactor Ld flows so as to be constant as the sum of the currents Iab and Iz, and therefore Iab decreases as Iz increases.

  At time t2, since Iz and Id become equal, Iab becomes 0. As the discharge progresses, the resonant capacitor Cz is completely discharged at time t4, and its current Iz becomes zero. On the other hand, since the current Id flowing through the filter reactor Ld is continuous, when the discharge current Iz of the resonant capacitor becomes 0, the current Id becomes the current Io that switches to the rectifier diodes D5 to D8. Thus, the continuity of the current Id is maintained.

  When the resonance current Iz flows through the freewheel diode D9 and the transformer primary current Iab becomes 0, when the gate control device 104 sends a turn-off signal to the semiconductor switches Q1 and Q4 at time t3 between time t2 and t4, and the turn-off occurs. The transformer primary side voltage Vab becomes 0, and a voltage equal to the input DC power supply voltage E is applied to Q1 and Q4. This is because a slight amount of excitation current remaining in the transformer freewheels along the path of the freewheel diode D3, the DC power supply 101, and the freewheel diode D2. Since the currents of the semiconductor switches Q1 and Q4 become almost zero at time t3, almost no switching loss occurs during the turn-off process.

  On the other hand, when the semiconductor switch Qz is turned on at the time t0, the resonance current Iz is gradually increased by the resonance reactor Lz. Therefore, the switching loss is small because Iz is still a small value in the turn-on transient state. In addition, when the semiconductor switch Qz is turned off during the period in which the free wheel diode D9 is conductive and the resonance current Iz is positive, the current of Qz is already 0, so that it can be seen that no switching loss occurs.

  At time t5, the gate control device 104 issues a turn-on command to the semiconductor switches Q2 and Q3 to start turn-on. At this time, the current Id flowing through the filter reactor Ld is equal to the current Io circulating through the rectifier diodes D5 to D8. At this time, the current Iab begins to flow through the resonant reactor Lz, and thus cannot be increased rapidly. Also, since Id can be regarded as constant, the sum of Io changes to Id. Therefore, Iab is a decrease in Io. It will increase. For this reason, almost no current flows in the turn-on transient state of Q2 and Q3. For this reason, the turn-on loss is small. This Iab increases gradually, becomes equal to Id at time t6, and Io becomes 0. The subsequent half cycle operates on the same principle as described above.

JP-A-4-368464 Japanese Patent Laid-Open No. 11-98836

O. Deblecker, A Moretti, and F. Vallee: “Comparative Analysis of Two Zero-Current Switching Isolated DC-DC Converters for Auxiliary Railway Supply,” SPEEDAM 2008.

  The description will be continued with reference to FIG.

  The first problem is that recovery characteristics (reverse recovery) when the diode is applied in the forward direction and a reverse voltage is applied immediately after the current starts flowing, the voltage recovers after the current flows in the reverse direction for a certain period of time. Characteristic). In FIG. 3, the current Io flows through the rectifier diodes D5 to D8 in the forward direction from time t4 to time t6. At time t5, a voltage is applied to the primary side, and current flows out through the resonant reactor Lz. At time t6, the current Io of this diode becomes zero. Immediately after this, the points c and d are short-circuited, and the current flowing through the resonant reactor Lz flows through the rectifier diodes D7 and D6 through two paths c, D5, e, D7, d and c, D6, f, d. A phenomenon occurs in which short circuit occurs in the direction in which the gas flows in the opposite direction. Thereafter, when the rectifier diodes D7 and D6 are reversely recovered and the current becomes zero, there is a problem that the current path that has flowed through the resonant reactor Lz disappears and an overvoltage is generated between the points e and f.

  Second, similarly to the first, at time t5, a stepped voltage is applied to the primary side of the transformer T by turning on the semiconductor switches Q2 and Q3. Since the stepped voltage includes up to high frequency components, depending on the frequency characteristics of the transformer T, resonance determined by the leakage inductance and stray capacitance occurs inside T, and an overvoltage is generated on the secondary side of T. Similarly, an overvoltage is generated between points e and f.

  Since the overvoltage due to the recovery of the two rectifier diodes and the frequency characteristics of the transformer occurs at approximately the same time between times t5 and t6, a voltage in which two jumping voltages are superimposed is generated between points e and f. There is a possibility of exceeding the withstand voltage of the rectifier diode, which may cause destruction of the element. Since the resonance capacitor Cz is not charged at this time and the voltage of Cz is 0, the voltage between the points e and f is directly applied to the resonance circuit control semiconductor switch Qz, and Qz is destroyed at the same time. There is a problem that it ends up.

  A known example that solves this problem is shown in FIG. 4, and a countermeasure method using the technique of FIG. 4 is described. 4, compared with the circuit of FIG. 2, a new connection is made between a connection point g of the resonance capacitor Cz of the resonance circuit 103 and the semiconductor switch Qz for resonance circuit control, and a connection point h of the filter reactor Ld of the filter circuit and the filter capacitor FC. The configuration is such that a snubber diode Ds is loaded. A series circuit of a snubber diode Ds and a resonant capacitor Cz is connected in parallel with the filter reactor Ld. When an overvoltage occurs due to the recovery of the diode and the frequency characteristics inside the transformer, the voltage at points e and f jumps high, but a current flows through the resonant capacitor Cz and the snubber diode Ds to charge Cz. The voltage Vz of this capacitor is maintained until the semiconductor switch Qz is turned on next time. Thus, when an overvoltage occurs between e and f, current flows through the bypass path of the resonant capacitor Cz, the snubber diode Ds, and the capacitor FC, so that an overvoltage suppression effect is produced. Although the resonance capacitor Cz is charged after the overvoltage is generated, the resonance circuit 103 operates, so that the charge stored in the resonance capacitor Cz is discharged and returns to 0. Therefore, the loss of the primary side semiconductor switch of the transformer T There is no influence on the circuit operation for reduction.

  The problem of this voltage suppression circuit is suppressed by forcibly bypassing the overvoltage generated in the transformer T and the rectifier diodes D5 to D8 by another path, and has not yet led to a fundamental cause solution.

  One means for solving the above problem is to provide a resonant circuit having a parallel circuit of a diode and a semiconductor switch, a resonant capacitor, and a resonant reactor on the DC output side of the rectifier diode bridge circuit.

  Furthermore, it may have a function of turning off the semiconductor switch of the power conversion circuit when the current flowing through the semiconductor switch of the power conversion circuit becomes almost zero.

  Alternatively, the transformer leakage inductance value is designed so that the voltage distribution on the primary side of the transformer does not include the series resonance frequency inside the transformer, and the overvoltage due to recovery of the rectifier diode does not exceed the element breakdown voltage of the rectifier diode bridge circuit. May be.

  Further, on / off control of the semiconductor switch in the power conversion circuit and the semiconductor switch in the resonance circuit may be controlled by the gate control device.

  Furthermore, the resonant circuit is a circuit in which a parallel circuit in which a diode and a semiconductor switch are connected in antiparallel, a resonant capacitor, and a resonant reactor are connected in series. The DC output of the rectifier diode bridge circuit and the filter circuit You may connect in parallel with a rectifier diode bridge circuit in between. Alternatively, the resonance reactor is connected in series between the DC output of the rectifier diode bridge circuit and the filter circuit, and a parallel circuit in which the diode and the semiconductor switch are connected in antiparallel and a circuit in which the resonance capacitor is connected in series. May be connected in parallel with the rectifier diode bridge circuit between the resonant reactor and the filter circuit.

  Alternatively, a resonant circuit in which a parallel circuit of a diode and a semiconductor switch and a resonant capacitor are connected in series is connected in parallel to the rectifier diode bridge circuit on the DC output side of the rectifier diode bridge circuit, and the leakage inductance value of the transformer is The primary voltage spectrum distribution may be a value that does not include the series resonance frequency inside the transformer, and an overvoltage due to recovery of the rectifier diode may be set to a value that does not exceed the element breakdown voltage of the rectifier diode bridge circuit. .

  According to the present invention, it is possible to reduce overvoltage caused by internal resonance of the transformer T, which inevitably occurs in the conventional circuit configuration, and overvoltage caused by recovery of the rectifier diode.

FIG. 1 shows a first embodiment of a DC power supply device according to the present invention. FIG. 2 shows a circuit configuration of a known example. FIG. 3 shows the time variation of the voltage current and the semiconductor switch command in a known configuration. FIG. 4 shows an example of a problem solving method in a known example. FIG. 5 shows an equivalent circuit of the transformer T when a diode bridge is connected. FIG. 6 shows the frequency characteristics of the impedance viewed from the primary side of the transformer T. FIG. 7 shows the time change of the voltage / current and the command of the semiconductor switch in FIG. 8A shows the frequency characteristics of the impedance of the transformer and the spectrum distribution of the input primary voltage, and FIG. 8B shows the relationship between the transformer leakage inductance and the overvoltage. FIG. 9 shows a second embodiment of the DC power supply device according to the present invention.

  First, the recovery phenomenon of the rectifier diode and the secondary overvoltage of the transformer T, which are problems in the prior art, will be considered.

First, an equivalent circuit when the rectifier diode bridges D5 to D8 are connected to the transformer T is shown in FIG. Referring to FIG. 5, a to d indicate the same positions as a to d shown in FIGS. 1, 2, and 4, and R <b> 1 and R <b> 2 are winding resistances on the primary and secondary sides of the transformer T, Lp1 and Lp2 indicate leakage inductances on the primary and secondary sides of the transformer, and Cp1 and Cp2 indicate stray capacitances on the primary and secondary windings of the transformer. Zab indicates the impedance when the secondary side is viewed from the primary side. The resonance reactor Lz in the conventional example includes the leakage inductance of the transformer T, and Lz is represented by the sum of Lp1 and Lp2. Considering the case where the semiconductor switches Q1 and Q4 are turned on and a voltage is applied to ab, the rectifier diodes D6 and D7 are recovered from the conductive state and turned off. The junction capacities of the rectifier diodes at this time are Cd6 and Cd7. FIG. 6 shows the frequency characteristics of the absolute value of the impedance Zab when the secondary side is viewed from the primary side of the transformer T in the equivalent circuit of FIG. This frequency characteristic has a series resonance point 106 inside the transformer at the frequency fr. This resonates in the series resonance path 105 that generates an overvoltage inside the transformer in the equivalent circuit of FIG. The series resonance frequency fr at this time is given by the following [Equation 1], the leakage inductance (L _P1 + L _P2 ) of the transformer T, the stray capacitance Cp1 of the transformer primary winding, and the stray capacitance Cp2 of the transformer secondary side. And the combined capacitance of the junction capacitances Cd6 and Cd7 of the rectifier diode.

  When a pulse-shaped waveform is applied to the primary voltage Vab of the transformer T, the spectrum is distributed to the high frequency component, and therefore the series resonance frequency fr inside the transformer is also included. Occurs on the next side.

  On the other hand, the overvoltage due to the recovery phenomenon of the diode is determined by the product of the resonant reactor Lz and the time rate of change (di / dt) of the diode current during recovery.

  From these, the fundamental solution to the problem of overvoltage generated in the transformer T and the rectifier diodes D5 to D8 is to reduce the leakage inductance of the transformer. As a result, the series resonance frequency fr is increased according to [Equation 1], so that it is possible to make the band not included in the turn-on waveform of the semiconductor switch, and at the same time, the overvoltage due to the rectifier diode recovery phenomenon can be reduced. It becomes possible.

  In the known examples of FIGS. 2 and 4, the resonance reactor Lz uses the leakage inductance of the transformer T. However, in the present invention, in order to prevent the overvoltage on the secondary side of the transformer T, the exciting inductance of the transformer T is provided. For example, as shown in FIG. 1 or 9, a resonant circuit 103 having a resonant reactor Lz and a resonant capacitor Cz that can be controlled by the semiconductor switch Qz is provided on the DC output side of the rectifier diodes D5 to D8. Connect and solve the overvoltage problem.

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

  Hereinafter, the configuration of the first embodiment of the present invention will be described with reference to FIG.

  101 is a DC power source, 102 is a filter circuit composed of a filter reactor Ld and a filter capacitor FC, 107 is a resonance circuit, and 104 is a gate control device for each semiconductor switch. Q1 to Q4 are semiconductor switches constituting an inverter circuit, and free wheel diodes D1 to D4 are attached to the respective semiconductor switches. The primary winding of the transformer T is connected between a connection point a between the semiconductor switches Q1 and Q2 and a connection point b between the semiconductor switches Q3 and Q4, and the secondary winding is a connection of a bridge made of rectifier diodes D5 to D8. Connected to points c and d. The output of this bridge is given to the load RL via the filter circuit 102.

  The gate control device 104 gives on / off commands to Q1 to Q4 and Qz. As the semiconductor switch, a bipolar transistor, a MOSFET, a thyristor, a gate turn-off thyristor, an IGBT, and the like can be considered. In this embodiment, an IGBT will be described as a representative example.

  In the configuration shown in FIG. 1, the exciting inductance of the transformer T is made as small as possible for manufacturing, and is instead added to the resonance circuit as a resonance reactor Lz.

  A resonance circuit 107 including a resonance reactor Lz and a resonance capacitor Cz that can be controlled by the semiconductor switch Qz is connected in series to the output sides e and f of the rectifier diodes D5 to D8. More specifically, the resonance circuit 107 is a circuit in which a semiconductor switch Qz to which a flywheel diode D9 is connected in antiparallel, a resonance reactor Lz, and a resonance capacitor Cz are connected in series. The resonant circuit 107 is inserted in parallel with the rectifier diode bridge circuit between the output side of the rectifier bridge and the filter circuit 102.

  FIG. 7 shows a time change of an operation waveform for explaining the operation of the embodiment shown in FIG. Since the basic operation is the same as that in FIG. 2 described in the technical background, the difference from this will be described. VC is the voltage across the resonant capacitor Cz, and VL is the voltage across the resonant reactor Lz. Vz is a voltage of the resonance circuit, and Io indicated by the sum of VC and VL indicates a current circulating from the rectifier bridge by the filter circuit 102 and the load RL.

  Assume that the gate control device 104 gives ON signals to Q1 and Q4, and the semiconductor switches Q1 and Q4 of the inverter circuit are in a conductive state. A current Iab flowing between the points a and b flows, and energy is transmitted from the DC power source 101 to the load RL. In the circuit operation, when a signal for turning on the semiconductor switch Qz of the resonance circuit 107 is supplied from the gate control device 104 at a time t0 before turning off the semiconductor switches Q1 and Q4 of the inverter circuit as in the known example, the resonance occurs when Qz is turned on. A charging current for the capacitor Cz flows from the DC power supply 101. This current Iz is a series resonance current of the resonance reactor Lz and the resonance capacitor Cz. From time t1 to t2, the same Iz as in the known example flows to charge the resonant capacitor Cz, and a voltage VC is generated across the resonant capacitor Cz. On the other hand, a voltage determined by the product of the time change of Iz and the inductance of the resonance reactor Lz is generated as VL.

  Since the charging is completed at time t1 and discharging is started, the current Iz becomes positive. However, since Iz changes with time, a substantially constant induced voltage continues to be generated at Lz. At time t2 thereafter, Iz and Id flowing through the filter reactor Ld become equal, and Iab becomes 0. Therefore, Iz becomes constant and changes with time, so the voltage VL becomes 0. At this time, the voltage Vz becomes equal to the voltage VC of the resonance capacitor Cz. Thereafter, the discharge proceeds in the same manner as in the known example, and eventually the resonant capacitor Cz is completely discharged at time t4, and its current Iz becomes zero. On the other hand, since the current Id flowing through the filter reactor Ld is continuous, when the discharge current Iz of the resonance capacitor becomes 0, the current Id is switched to the rectifier diodes D5 to D8 and flows into the current Io, and the current continuity is maintained. It is.

  Regarding the turn-off of the semiconductor switches Q1 and Q4, a gate-off signal is sent from the gate control device 104 at time t3 between times t2 and t4 to turn it off. Since the current flowing through the semiconductor switches Q1 and Q4 becomes almost zero at the time t3, switching with little loss is possible in the turn-off process. Here, the substantially zero current flowing through the semiconductor switches Q1 and Q4 at time t3 is an exciting current of the transformer. The value depends on the design of the transformer and the drive frequency of the semiconductor switch. For example, when the drive frequency is 4 kHz, the current is 2% or less of the current rating of the semiconductor switch and the current is 24A or less for a 1200A semiconductor switch. Like that.

  In the case of the present embodiment, only the resonance current component of the resonance reactor Lz and the resonance capacitor Cz flows through the resonance reactor Lz, and the direct current component that is the load current of the main circuit does not flow, so the resonance reactor Lz may be a small reactor.

  However, it is difficult to make the leakage inductance of the transformer T zero. An example of determining the limit value of the leakage inductance will be described with reference to FIG. When the semiconductor switch connected to the primary side of the transformer T is turned on, an overvoltage is generated due to the spectral distribution of the primary side voltage waveform of the transformer T and the internal resonance characteristics of the transformer. Therefore, as shown in FIG. 8A, the leakage inductance value of the transformer T is set so that the spectral distribution of the voltage on the primary side of the transformer T does not include the series resonance frequency fr inside the transformer given by [Equation 1]. By doing so, it is possible to prevent overvoltage due to resonance. Under this condition, as shown in FIG. 8B, the limit value of the transformer leakage inductance is set so that the overvoltage due to the recovery of the rectifier diode does not exceed the allowable value of the element breakdown voltage of the rectifier diode.

  Another embodiment different from the first embodiment will be described below with reference to FIG.

  The present invention can also be realized in the form of FIG. Also in this embodiment, the resonance circuit 108 includes a semiconductor switch Qz, a resonance capacitor Cz, and a resonance reactor Lz, to which a free wheel diode D9 is connected in antiparallel. Specifically, a circuit in which a semiconductor switch Qz to which a freewheel diode D9 is connected in antiparallel and a resonant capacitor Cz are connected in series is connected to a point f between the output point e of the rectifier bridge and the filter reactor Ld. The resonance reactor Lz is inserted between the output point e and the point f of the rectifier bridge.

  In other words, the resonance reactor Lz is inserted between the output point e of the rectifier diode and the filter reactor Ld connection point f.

  The operating principle and waveform are the same as in the first embodiment. However, in this case, unlike the first embodiment, a larger reactor is required compared to the first embodiment in that the direct current component of the load current flows continuously through the resonant reactor Lz. However, this configuration is effective when the value of Lz can be satisfied by the wiring inductance due to the convenience of the wiring.

  According to each of the embodiments described above, there is an effect of simultaneously reducing the overvoltage caused by internal resonance of the transformer T and the overvoltage caused by recovery of the rectifier diode, which are inevitably generated in the conventional circuit configuration.

  In addition, since the configuration is such that the cause of the overvoltage on the secondary side is eliminated, no countermeasure against the overvoltage is required. That is, in the known example 2, the overvoltage is bypassed by introducing the snubber diode Ds. However, the reduction of such semiconductor elements leads to an improvement in the reliability of the entire apparatus.

  On the other hand, in the conventional example, the resonant reactor Lz is configured as a leakage inductance of the transformer T, and no additional reactor is required. However, in the present invention, an additional reactor connected to the DC output side of the rectifier diodes D5 to D8 is used. For this reason, the degree of freedom of the combination of the resonant reactor Lz and the resonant capacitor Cz is increased, so that the degree of freedom of design such as the rating of the semiconductor switch can be greatly increased.

  In particular, in the form shown in the first embodiment, the resonance reactor Lz does not flow the main circuit current flowing through the load, but only the resonance current.

  Thus, the present invention has a configuration in which a resonance circuit is simply added to a conventional circuit, and a wide voltage control range can be obtained and controllability is good. Further, the omission of the snubber circuit further improves the reliability as compared with the known example, and if it is added to a PWM control inverter circuit with a proven track record, a great effect is produced. Of course, as in the known example, the present invention includes effects of reducing the size and weight by increasing the switching frequency, simplifying the cooling device, and reducing high-frequency electromagnetic noise.

  Note that the resonance reactor Lz in the present invention is not necessarily intended to be a device that increases the reactor, but may use the inductance of the wiring itself.

DESCRIPTION OF SYMBOLS 101 DC power supply 102 Filter circuit 103,107,108 Resonance circuit 104 Gate control apparatus 105 Series resonance path 106 which generate | occur | produces an overvoltage inside a transformer Series resonance point Cd6 inside a transformer Cd7 Junction capacity Cd7 of rectification diode D7 Junction capacity of rectification diode D7 Cp1 Primary side stray capacitance in equivalent circuit of transformer T Cp2 Secondary side stray capacitance in equivalent circuit of transformer T Resonant capacitors D1-D4, D9 Free wheel diode D5-D8 Rectifier diode Ds Snubber diode E Input DC power supply voltage FC Filter capacitor Fr Frequency of series resonance generated inside transformer Ld Filter reactor Lm Excitation inductance Lp1 in equivalent circuit of transformer T Primary side leakage inductance Lp2 in equivalent circuit of transformer T Secondary side leakage inductance Lz in equivalent circuit of T Resonance reactors Q1-Q4 Semiconductor switch Qz Semiconductor switch R1 for resonance circuit control Primary winding resistance R2 in equivalent circuit of transformer T Secondary winding resistance RL in equivalent circuit of transformer T Load T Transformer Zab Transformer T Impedance seen from the primary side to the secondary side

Claims (7)

DC power supply, power conversion circuit capable of generating AC from DC, primary winding of transformer connected to output of power conversion circuit, secondary winding of transformer, and secondary winding connected to secondary winding A rectifier diode bridge circuit;
A filter circuit composed of a reactor and a capacitor and connected to the output side of the rectifier diode bridge circuit;
In a DC power supply device having
A resonant circuit having a parallel circuit of a diode and a semiconductor switch, a resonant capacitor, and a resonant reactor is provided between the DC output side of the rectifier diode bridge circuit and the filter circuit ,
During the period when all the semiconductor switches included in the power conversion circuit are off, the current flowing through the reactor of the filter circuit flows through the rectifier diode bridge circuit,
The value of the leakage inductance of the transformer, the spectrum distribution of the voltage on the primary side of the transformer is the series resonance frequency due to the leakage inductance of the transformer, the stray capacitance of the transformer, and the junction capacitance of the rectifier diode of the rectifier diode bridge circuit. A DC power supply device characterized in that it is set not to include . The DC power supply device according to claim 1,
A DC power supply device, wherein the semiconductor switch of the power conversion circuit is turned off when a current flowing through the semiconductor switch of the power conversion circuit becomes almost zero. The DC power supply device according to claim 1 or 2,
The semiconductor switch of the power conversion circuit is all off, and after the resonant capacitor has been discharged, the current flowing through the reactor of the filter is switched to the rectifier diode bridge circuit and flows . DC power supply. The DC power supply device according to any one of claims 1 to 3,
ON / OFF control of the semiconductor switch in the power conversion circuit and the semiconductor switch in the resonance circuit is controlled by a gate control device. The DC power supply device according to any one of claims 1 to 4,
The resonant circuit comprises a parallel circuit in which the said diode semiconductor switches are connected in antiparallel, and the resonant capacitor, the resonant reactor is a circuit but connected in series,
A DC power supply apparatus, wherein the DC power supply device is connected in parallel with the rectifier diode bridge circuit between a DC output of the rectifier diode bridge circuit and the filter circuit. The DC power supply device according to any one of claims 1 to 4,
The resonant reactor is connected in series between the DC output of the rectifier diode bridge circuit and the filter circuit,
A circuit in which the parallel circuit in which the diode and the semiconductor switch are connected in antiparallel and a resonant capacitor are connected in series is connected in parallel with the rectifier diode bridge circuit between the resonant reactor and the filter circuit. DC power supply characterized by the above. DC power supply, power conversion circuit capable of generating AC from DC, primary winding of transformer connected to output of power conversion circuit, secondary winding of transformer, and secondary winding connected to secondary winding A rectifier diode bridge circuit;
In a DC power supply device having a reactor and a capacitor, and a filter circuit connected to the output side of the rectifier diode bridge circuit,
A resonance circuit in which a parallel circuit of a diode and a semiconductor switch and a resonance capacitor are connected in series is connected between the DC output side of the rectifier diode bridge circuit and the filter circuit, and is connected in parallel to the rectifier diode bridge circuit. Installed in
During the period when all the semiconductor switches included in the power conversion circuit are off, the current flowing through the reactor of the filter circuit flows through the rectifier diode bridge circuit,
The leakage inductance value of the transformer, contains a spectral distribution of the transformer leakage inductance of the primary side voltage of the transformer, and the stray capacitance of the transformer, the series resonance frequency due to the junction capacitance of the rectifier diode of the rectifier diode bridge circuit No value,
A DC power supply device, wherein an overvoltage due to recovery of the rectifier diode is set to a value that does not exceed an element breakdown voltage of the rectifier diode bridge circuit.

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