JP5582361B2 - Power conversion device and power supply system - Google Patents

Description

  The present invention relates to a power conversion device including at least a switching element and a transformer, and a power supply system including the power conversion device.

  Conventionally, there is no need to provide a gap in the transformer, and an example of a technique related to a demagnetization prevention circuit for the purpose of preventing a demagnetization phenomenon by a circuit control technique has been disclosed (see, for example, Patent Document 1). . When the positive DC component resulting from the characteristics of the conversion elements (S1 to S4) is generated in the output of the inverter circuit, the demagnetization prevention circuit converts the conversion element (S1) every anti-cycle in which the AC output of the inverter circuit becomes negative. The time width of the pulse signal for activating S4) is increased according to the magnitude of the positive DC component (see paragraph 0033 of the same document).

  In addition, an example of a technique related to a demagnetization prevention circuit of a high-frequency transformer intended to suppress a saturation phenomenon due to demagnetization with a simple and inexpensive configuration is disclosed (for example, see Patent Document 2). The demagnetization prevention circuit of this high-frequency transformer is a Td creation circuit (31) including a CR circuit and an AND circuit (34) composed of a variable resistor (32) and a capacitor (33). In the Td creation circuit (31), since the CR circuit works as a delay time element with respect to the gate signal, the delay time (Td1) at which the U phase and the Y phase are turned on, the V phase that generates a negative voltage, and the X phase By adjusting separately the delay time (Td2) of the phase turn-on timing, the difference between the positive and negative on-time widths (Δt) is adjusted in advance (see paragraphs 0020-0022 of the same document). ).

Japanese Patent Laid-Open No. 06-098559 Japanese Patent No. 3501548

  However, when the technique of Patent Document 1 is applied and a negative DC component due to the characteristics of the conversion elements (S1 to S4) is generated, the bias of the transformer cannot be suppressed. That is, in the circuit configuration shown in FIG. 1 of Patent Document 1, the time width of the pulse signal for operating the conversion elements (S1 to S4) cannot be increased according to the magnitude of the negative DC component. Although it is possible to deal with the positive and negative DC components caused by the characteristics of the conversion elements (S1 to S4), respectively, it is necessary to provide a demagnetization prevention circuit corresponding to each of the positive and negative DC components. become.

  Moreover, in the technique of patent document 2, the electric current (I) which flows through the secondary side circuit of a transformer (4) is detected by the 1st current sensor (10) (refer FIG. 4 of patent document 2). Thus, when using the DC deviation signal from one current sensor, it can be suppressed in terms of cost and physique. On the other hand, it is necessary to separate the current sensor signals in cooperation with the pulse drive timing, which easily leads to a complicated circuit configuration. In general, the current tends to be more complicated in the measurement circuit than the voltage. Therefore, if the technique of Patent Document 2 is applied to an insulation type power converter, it is necessary to insulate and measure the current, and thus the current measurement tends to be complicated.

  The present invention has been made in view of such a point, and can cope with positive and negative DC components while suppressing cost, and without adding a circuit element to a current flowing path, it is possible to prevent the transformer from being demagnetized. An object of the present invention is to provide a power conversion device and a power supply system that can suppress (including reduction).

  The invention according to claim 1, which has been made to solve the above problem, includes at least a switching element that performs switching based on an operation signal, and a transformer that electrically connects the switching element to a primary terminal. And two or more rectifiers for rectifying AC power output from the secondary terminal of the transformer, and an integrated waveform for outputting a waveform obtained by individually integrating DC power rectified by the two or more rectifiers Of the two or more waveforms output from the integrated waveform output unit, a peak hold unit that holds a peak value for one waveform, and two or more waveforms output from the integrated waveform output unit A difference value detection unit for detecting a difference value between a waveform value of the waveform excluding the one waveform and a peak value held by the peak hold unit; and the difference value Based on the difference value detected by the detection section, and having an operation signal controller for controlling an operation signal for operating the switching element.

  According to this configuration, the operation signal control unit is based on the difference value between the waveform value of the current waveform output from the integrated waveform output unit (that is, the integrated waveform) and the peak value already held by the peak hold unit. Outputs an operation signal for operating the switching element. In other words, since the control is performed so that the operation signal is changed so that the waveform value of the current waveform becomes equal to the peak value, it is possible to suppress the bias of the transformer in advance (including suppression and reduction; hereinafter the same meaning). . By making each rectifying unit correspond to positive and negative DC power, it is possible to prevent the transformer from being demagnetized regardless of whether it is positive or negative. Since it is only necessary to provide a rectifying unit corresponding to the positive / negative of the AC power output from the secondary terminal of the transformer without adding a circuit element to the current flow path, the cost of the entire apparatus can be suppressed.

  The “switching element” includes two switching elements connected in series by upper and lower arms, and any semiconductor element capable of switching operation can be applied. For example, an FET (specifically, MOSFET, JFET, MESFET, etc.), IGBT, GTO, power transistor, or the like is applicable. “Power” includes power by voltage control and power by current control. The “rectifier unit” is configured by a rectifier circuit, a rectifier, or the like, and includes half-wave rectification and full-wave rectification. The “operation signal” is arbitrary regardless of the type as long as it is a signal capable of switching the switching element. An on signal for turning on the switching element and an off signal for turning off the switching element are included. It does not ask | require an analog signal and a digital signal including a pulse signal.

  The invention according to claim 2 is characterized in that the operation signal control unit operates on / off of the switching element relating to a waveform excluding the one waveform based on the difference value. Waveforms other than one waveform are formed by the operation of switching elements that are separate from the switching elements that form one waveform. According to this configuration, by changing the operation signal for the separate switching element, the current waveform value is controlled to be equal to the peak value. Therefore, it is possible to reliably suppress the bias magnetism of the transformer.

  According to a third aspect of the present invention, when the difference value reaches zero (numerical value “0”), the operation signal control unit operates on / off of the switching element relating to a waveform other than the one waveform. It is characterized by doing. According to this configuration, when the difference value reaches zero, control is performed to turn on / off a switching element that is separate from the switching element that forms one waveform. Therefore, it is possible to reliably suppress the bias magnetism of the transformer.

  According to a fourth aspect of the present invention, the operation signal control unit sets a timing for outputting the operation signal in consideration of a time lag from when the operation signal is output to when the on / off of the switching element changes. The output is made earlier by the time lag period. According to this configuration, the operation signal controller outputs the operation signal for operating the switching element earlier by the time lag period. In this way, the operation signal is transmitted to the switching element in anticipation of the time lag, so that it is possible to more reliably suppress the magnetic bias that may occur in the transformer. Note that the above time lag means “a period from when the operation signal is output until the switching element is turned on / off”. However, in order to more reliably suppress the magnetic bias that may occur in the transformer, the “difference value is detected. It is desirable to include a period from when the operation signal is output to when the operation signal is output.

  According to a fifth aspect of the present invention, in the power supply system, the power conversion device according to any one of the first to fourth aspects is provided, and the connection unit that electrically connects the output terminals of the two or more rectification units And a filter unit for reducing the AC component of the DC power in the connection unit. According to this configuration, it is possible to provide a power supply system that can cope with positive and negative DC components while suppressing cost and can prevent the transformer from being demagnetized without adding circuit elements to the current flow path.

It is a schematic diagram which shows the 1st structural example of the power supply system containing a power converter device. It is a flowchart which shows the 1st procedure example of an operation signal process. It is a time chart which shows the 1st control example which suppresses the magnetic bias of a transformer. It is a time chart which shows the 2nd control example which suppresses the bias magnetism of a transformer. It is a time chart which shows the 3rd control example which suppresses the bias magnetism of a transformer. It is a flowchart which shows the 2nd procedure example of an operation signal process. It is a time chart which shows the 4th control example which suppresses the magnetic bias of a transformer. It is a schematic diagram which shows the 2nd structural example of the power supply system containing a power converter device. It is a schematic diagram which shows the other structural example of a switching part.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Unless otherwise specified, “connect” means electrical connection. Each figure shows elements necessary for explaining the present invention, and does not show all actual elements. When referring to directions such as up, down, left and right, the description in the drawings is used as a reference. The continuous code is simply expressed using the symbol “˜”. For example, “switching elements Q1 to Q4” means “switching elements Q1, Q2, Q3, Q4”. “On (true)” and “off (false)” will be described on the assumption of positive logic, but it goes without saying that it can also be implemented with negative logic.

[Embodiment 1]
The first embodiment is an example of suppressing the bias of the transformer based on the electric power by voltage control, and will be described with reference to FIGS. First, FIG. 1 is a schematic diagram illustrating a first configuration example of a power supply system including a power conversion device.

  A power supply system 10 shown in FIG. 1 is a so-called “DC-DC converter”, and uses a DC voltage (for example, 300 [V]) supplied from a power source Edc (for example, a battery or a fuel cell) as a target voltage (for example, 300 [V]). For example, it has a function of converting to 12 [V] or the like and outputting to the output device 30. The power supply system 10 includes a power conversion device 20, and includes a choke coil L10, capacitors C10 and C11, diodes D11 and D12, a filter unit 12, and the like.

  For example, a battery or a fuel cell is used as the power source Edc that supplies a DC voltage (corresponding to “DC power”). The plus terminal and minus terminal of the power source Edc are connected to the power converter 20 via the choke coil L10 and the capacitor C10. The choke coil L10 functions as an input filter. Capacitor C10 repeatedly charges and discharges the DC voltage. Before describing the remaining diodes D11 and D12, the capacitor C11, the filter unit 12, and the like, the configuration and operation of the power conversion device 20 will be described below for convenience of description.

  The power conversion device 20 is a so-called “inverter” and has a function of converting a DC voltage supplied from the power source Edc into an AC voltage (corresponding to “AC power”) and outputting the AC voltage. This power conversion device 20 includes switching elements Q1 to Q4, diodes D1 to D4, transformer Tr1, diodes D21 and D22, operation signal control unit 21, integral waveform output units 22 and 23, peak hold unit 24, and difference value detection unit 25. Etc.

  The switching elements Q1 to Q4 are driven on / off in accordance with operation signals individually transmitted from an operation signal control unit 21 described later. For example, N-channel MOSFETs are used for the switching elements Q1 to Q4 of this embodiment. Switching element Q1 and switching element Q3 are connected in series by upper and lower arms, and switching element Q2 and switching element Q4 are connected in series by upper and lower arms. The group of switching elements Q1, Q3 and the group of switching elements Q2, Q4 are connected in parallel. A connection point between the switching element Q1 (source terminal) and the switching element Q3 (drain terminal) is connected to a primary terminal (one end side) of the transformer Tr1. Similarly, the connection point between the switching element Q2 (source terminal) and the switching element Q4 (drain terminal) is connected to the primary terminal (the other end side) of the transformer Tr1.

  The diodes D1 to D4 may be connected in parallel corresponding to the switching elements Q1 to Q4, respectively, and function as a freewheel diode. Therefore, it may be incorporated in the switching elements Q1 to Q4 or may be externally attached.

  As the transformer Tr1, for example, a transformer having at least three terminals as secondary terminals in addition to the primary terminal and outputting a two-phase voltage with reference to the potential of the intermediate terminal (intermediate tap) is used. With reference to the potential of the intermediate terminal, a positive secondary voltage Vs1 is output to the secondary terminal on one side, and a negative secondary voltage Vs2 is output to the secondary terminal on the other side. The secondary voltages Vs1 and Vs2 correspond to “AC power”, respectively. Switching elements Q1, Q4 are involved in the output of the secondary voltage Vs1, and switching elements Q2, Q3 are involved in the output of the secondary voltage Vs2 (see also FIGS. 3 to 5).

  When viewed in each cycle, if the voltage-time product applied to the secondary voltages Vs1, Vs2 is not equal, the magnetization is generated, and if the voltage-time product is equal, the magnetization is not generated. This “voltage time product” is indicated by an integrated value of the secondary voltages Vs1 and Vs2 output from the secondary terminal of the transformer Tr1 and the time output for each voltage. For example, the output time of the secondary voltage Vs1 is assumed to be “T1”, and the output time of the secondary voltage Vs2 is assumed to be “T2”. Under this assumption, the voltage time product of the secondary voltage Vs1 involving the switching elements Q1 and Q4 is “Vs1 × T1”, and the voltage time product of the secondary voltage Vs2 involving the switching elements Q2 and Q3 is “Vs2 × T2”. "become.

  A diode D22, an integrated waveform output unit 23, and a peak hold unit 24 are connected in series between the secondary terminal on one side where the secondary voltage Vs1 is generated and the plus terminal of the difference value detection unit 25. The diode D21 and the integrated waveform output unit 22 are connected in series between the other secondary terminal where the secondary voltage Vs2 is generated and the minus terminal of the difference value detection unit 25.

  The integrated waveform output units 22 and 23 have a function of individually outputting integrated waveforms obtained by integrating the DC voltages rectified by the diodes D21 and D22, respectively. The integral value of the integral waveform changes from moment to moment according to the period during which the secondary voltages Vs1 and Vs2 are applied. The integrated waveform varies depending on the configuration of the integrated waveform output unit 22, the time constant, and the like, but it is desirable to adjust so that a triangular wave is obtained according to the secondary voltages Vs1 and Vs2. The integrated waveform output units 22 and 23 of this embodiment are each composed of a resistor and a capacitor in order to keep costs low. As shown, one end of the capacitor is connected to the resistor, and the other end is connected to the ground N. Note that the potential of the ground N is not necessarily 0 [V].

  The peak hold unit 24 receives the waveform value W1 of the waveform (that is, the integrated waveform) output from the integrated waveform output unit 23 based on the secondary voltage Vs1, and holds the peak value Wp that is the maximum value of the waveform value W1. Output. However, when a reset signal is received from the operation signal control unit 21 (specifically, the control circuit 21b), the peak value Wp is reset to a predetermined value (for example, 0).

  The difference value detection unit 25 calculates a difference value Δd indicating a difference between the peak value Wp output from the peak hold unit 24 and the waveform value W2 of the waveform output from the integrated waveform output unit 22 based on the secondary voltage Vs2. Detect and output. The differential value detection unit 25 of this embodiment uses a differential amplifier such as a differential amplifier circuit using an operational amplifier, for example. Specifically, the peak value Wp based on the secondary voltage Vs1 is input to the plus terminal, and the waveform value W2 based on the secondary voltage Vs2 is input to the minus terminal. When the amplification factor is assumed to be “1”, a difference value Δd (= Wp−W2) is output.

The operation signal control unit 21 includes a drive circuit 21a, a control circuit 21b, and the like. The operation signal control unit 21 performs control to change the operation signal based on the above-described difference value Δd. The operation signal is a signal that is individually transmitted to the switching elements Q1 to Q4 to be turned on / off. For example, a pulse signal is used as the operation signal of this embodiment. The control circuit 21 b governs the overall operation of the power conversion device 20. In realizing the present invention, when the difference value Δd transmitted from the difference value detection unit 25 becomes zero, the control circuit 21b drives the switching circuit 21a so as to switch on / off the switching element that is currently driven. A command signal Vc ^* for driving is output. The drive circuit 21a generates the above-described operation signal (pulse signal) based on the command signal Vc ^* transmitted from the control circuit 21b, and individually outputs (transmits) it to the switching elements Q1 to Q4.

  The power conversion device 20 configured as described above outputs two-phase secondary voltages Vs1 and Vs2 with reference to the potential of the intermediate terminal from the transformer Tr1. In the power supply system 10, the intermediate terminal of the transformer Tr1 is connected to the ground N. In order to perform two-phase full-wave rectification, the secondary voltage Vs1 is rectified by the diode D11, the secondary voltage Vs2 is rectified by the diode D12, and is connected (directly connected) at the connection portion J after both rectifications. The diodes D11 and D12 each correspond to a “rectifying unit”. Since the rectified DC voltage is merely synthesized at the connection portion J, it is smoothed by the capacitor C11, and the AC component (for example, high-frequency component and pulsation) is removed (including reduction by the filter portion 12; the same applies hereinafter). ) The filter unit 12 includes a reactor L12 (coil), a capacitor C12, and the like. The stabilized DC voltage is output to the output device 30. Any device that requires a predetermined DC voltage can be applied to the output device 30.

A control example for suppressing (including reducing) the magnetic bias when the magnetic bias occurs in the transformer Tr1 included in the power supply system 10 will be described with reference to FIG. FIG. 2 is a flowchart showing a first procedure example of the operation signal processing. This operation signal process is one of the control processes performed by the control circuit 21b shown in FIG. 1, and is repeatedly executed while the control circuit 21b operates. Since the control circuit 21b outputs the command signal Vc ^* to perform switching of the switching elements Q1 to Q4, it is natural to determine which switching element is currently turned on / off, the cycle of each switching element, and the like. I know.

  In the operation signal processing shown in FIG. 2, if the timing for starting the input of the difference value Δd has not been reached (NO in step S10), the operation signal processing is returned. On the other hand, when the timing for starting the input of the difference value Δd is reached (YES in step S10), the input of the difference value Δd from the difference value detecting unit 25 is started [step S11].

  The “timing to input the difference value Δd” in step S11 can be arbitrarily set, but the timing at which the difference value Δd becomes other than zero is desirable. For example, one cycle of a specific switching element among the switching elements Q1 to Q4 is applicable. The time charts of FIGS. 3 to 5 to be described later are examples in which the “specific switching element” is the switching element Q1, and the switching element Q1 has a timing of rising from OFF to ON.

  If the difference value Δd input in step S11 is not zero (NO in step S13), the operation signal processing is returned because the transformer Tr1 is demagnetized. Specifically, the transformer Tr1 is demagnetized based on the secondary voltage Vs1 output in association with the switching elements Q1 and Q4.

  Thereafter, if the difference value Δd input in step S11 is zero (YES in step S13), the voltage time products applied to the secondary voltages Vs1 and Vs2 described above are equal. Therefore, the reset signal is transmitted to the peak hold unit 24 to be reset, and the operation signal transmitted to the required switching element is changed [Step S14], and the input of the difference value Δd from the difference value detection unit 25 is stopped. [Step S15] The operation signal processing is returned.

  The difference value Δd becomes zero in step S13 because the waveform value W2 applied to the secondary voltage Vs2 output in association with the switching elements Q2 and Q3 is equal to the peak value Wp applied to the secondary voltage Vs1. Means that. That is, since the voltage time products applied to the secondary voltages Vs1 and Vs2 are equal, the magnetic bias generated in the transformer Tr1 disappears. Accordingly, in step S14, the operation signal is changed so that one or both of the switching elements Q2 and Q3 fall from on to off.

  Note that, as illustrated by a two-dot chain line, it is desirable to determine the timing for changing the operation signal in consideration of the time lag before the determination of the difference value Δd in Step S13 [Step S12]. This time lag is a period required from when the operation signal is output until the switching element is turned on / off. That is, in step S14, control is performed so that the operation signal is output ahead of the time lag period, so that the difference value Δd becomes zero at the timing when the switching element is changed. Assuming that the difference value Δd corresponding to the time lag period is “threshold α”, the process branches depending on whether or not the difference value Δd is equal to or less than the threshold value α (0 ≦ Δd ≦ α) as shown in parentheses in step S13. As the “threshold value α” corresponding to the time lag period, it is desirable to set an appropriate numerical value applied to the power converter 20 by performing an experiment or a field test. Specifically, it is recorded in advance on a recording medium in the control circuit 21b, or input from an external device (for example, ECU or the like) connected so as to be accessible through a communication line (regardless of wired / wireless).

  Operation signal control examples 1 to 4 for executing the operation signal processing shown in FIG. 2 and changing the operation signals transmitted to the switching elements Q1 to Q4, respectively, to suppress the bias of the transformer Tr1 in advance will be described with reference to FIG. Description will be made with reference to FIG. In order to simplify the explanation, in the operation signal control examples 1 to 4, control based on the cycle of the switching element Q1 will be described.

(Operation signal control example 1)
The operation signal control example 1 is an example in which the operation signal to the switching element Q2 is changed on the basis of the cycle of the switching element Q1, and will be described with reference to FIG. FIG. 3 shows changes with time of switching elements Q1, Q3, Q2, Q4, peak value Wp, waveform value W2, and operation signal to switching element Q2 (switching element Q3 in FIG. 7) in order from the top. . The on state of each switching element is “on”, and the off state is “off”. The waveform value W1 is indicated by a two-dot chain line superimposed on the peak value Wp. In order to facilitate understanding, each change in the waveform values W1 and W2 is shown linearly, but changes in a curve depending on the configuration of the integrated waveform output units 22 and 23, the time constant, and the like. The same applies to FIGS. 4 to 7 described later.

  One cycle of the switching element Q1 shown in FIG. 3 is a cycle Cy1 (period from time t11 to time t16), a period Cy2 (period from time t16 to time t1b), a period Cy3 (period after time t1b), and the like. . Control is performed so that no bias is generated in the transformer Tr1 within each cycle. The cycles Cy1, Cy2, Cy3,... Have basically the same time length (period), but can be controlled even when they have different time lengths. Since the control is performed so that the bias is not generated in the transformer Tr1 within one cycle, the cycle Cy1 will be described below as a representative.

  From time t11 to time t12, since the switching elements Q1 and Q4 are simultaneously turned on, the secondary voltage Vs1 is output from the secondary terminal of the transformer Tr1. As the secondary voltage Vs1 is generated, the waveform value W1 output from the integrated waveform output unit 23 increases, and decreases after time t12 as indicated by a two-dot chain line. As the waveform value W1 changes, the peak value Wp increases from time t11 to time t12 and reaches the maximum value Wx at time t12. The peak hold unit 24 holds and outputs the maximum value Wx after time t12 (until time t14 reset by the control circuit 21b).

  After time t12, switching elements Q2 and Q3 are simultaneously turned on at time t13, so that secondary voltage Vs2 is output from the secondary terminal of transformer Tr1. As the secondary voltage Vs2 is generated, the waveform value W2 output from the integrated waveform output unit 22 increases.

  As described above, in the difference value detection unit 25, the peak value Wp is input to the plus terminal, and the waveform value W2 is input to the minus terminal. Therefore, the difference value Δd output from the difference value detection unit 25 increases with the increase of the peak value Wp from time t11, becomes constant at the maximum value dx from time t12, and decreases with the increase of the waveform value W2 from time t13. become.

  In the operation signal processing of FIG. 2, it is determined that the timing for starting the input of the difference value Δd has been reached at time t11 when the switching element Q1 rises from OFF to ON (step S10). Therefore, the difference value Δd starts to increase from time t11 and becomes constant at the maximum value Wx from time t12. However, since the difference value Δd starts to decrease from time t13 and the difference value Δd becomes zero at time t14 (YES in step S13), the operation signal of the switching element Q2 is changed (ON to OFF) (step S14). ), The input of the difference value Δd from the difference value detection unit 25 is stopped (step S15).

  By the control of the operation signal processing, the switching element Q2, which was originally scheduled to be lowered from on to off at time t15 in accordance with the duty ratio Dr2a, is forcibly lowered from on to off at time t14 (see arrow Da). reference). At time t14 when the switching element Q2 is turned off, the secondary voltage Vs2 is not output to the secondary terminal of the transformer Tr1, and the waveform value W2 is also zero. At the time when the waveform value W2 becomes zero (or until the next time t16 when the switching element Q1 rises from off to on), the peak hold unit 24 is reset so that the peak value Wp becomes zero. Thus, the voltage time product of the secondary voltage Vs1 involving the switching elements Q1 and Q4 and the voltage time product of the secondary voltage Vs2 involving the switching elements Q2 and Q3 are substantially the same, and the period Cy1 is biased toward the transformer Tr1. Magnetism is not generated. Even if the magnetization is generated, the amount of the magnetization is very small, so that the influence on the power supply system 10 as a DC-DC converter can be almost ignored. Each cycle after the cycle Cy2 is similarly controlled. Therefore, no bias is generated in the transformer Tr1 in all cycles, and the bias in the transformer Tr1 can be suppressed in advance.

  The switching element Q2 that receives the change in the operation signal is forcibly lowered from on to off at times t14, t19,. As a result, the duty ratio Dr2b (Dr2b <Dr2a) is obtained in each cycle after time t11. In other words, it can be regarded as control by changing the duty ratio. However, when the power supply start timing is time t11, the duty ratio Dr2b does not change in all cycles.

(Operation signal control example 2)
The operation signal control example 2 will be described with reference to FIG. This operation signal control example 2 is an example in which the operation signal to the switching element Q3 is changed on the basis of the cycle of the switching element Q1, similarly to the operation signal control example 1 described above. Since only the object to which the operation signal is changed is different, the difference from the operation signal control example 1 will be described below. Therefore, the same control contents as those of the operation signal control example 1 are denoted by the same reference numerals as those in FIG.

  The operation signal control example 2 is different from the operation signal control example 1 in the switching element that is the target of changing the operation signal in the operation signal processing of FIG. 2 (step S14). The switching elements Q2 and Q3 are involved in the secondary voltage Vs2 output to the secondary terminal of the transformer Tr1. That is, the secondary voltage Vs2 is output only when both the switching elements Q2 and Q3 are turned on. In the operation signal control example 1, the operation signal of the switching element Q2 is changed. In the operation signal control example 2, the same effect can be obtained even when the operation signal of the switching element Q3 is changed. This point will be described with reference to FIG.

  Similarly to the operation signal control example 1, since the switching elements Q2 and Q3 are simultaneously turned on from time t13, the secondary voltage Vs2 is output from the secondary terminal of the transformer Tr1, and the waveform value output from the integrated waveform output unit 22 W2 increases. When the difference value Δd decreases with this increase, the difference value Δd becomes zero at time t14 (YES in step S13 in FIG. 2). At this time, the operation signal of the switching element Q3 is changed (from on to off) (step S14 in FIG. 2), and input of the difference value Δd from the difference value detection unit 25 is stopped (step S15 in FIG. 2).

  By the control of the operation signal processing, the switching element Q3 that was originally scheduled to fall from on to off at time t20 in accordance with the duty ratio Dr3a is forcibly lowered from on to off at time t14 (see arrow Db). reference). At time t14 when the switching element Q3 is turned off, the secondary voltage Vs2 is not output to the secondary terminal of the transformer Tr1, and the waveform value W2 is also zero. Each cycle after cycle Cy2 is similarly controlled. As in the case of the operation signal control example 1, no bias is generated in the transformer Tr1 in all cycles, and the bias in the transformer Tr1 can be suppressed in advance.

(Operation signal control example 3)
The operation signal control example 3 will be described with reference to FIG. This operation signal control example 3 is an example in which the operation signal to the switching element Q2 is changed on the basis of the cycle of the switching element Q1, similarly to the operation signal control example 1 described above. However, it differs from the operation signal control example 1 in that the operation signal to the switching element Q2 is changed in consideration of the time lag required from when the operation signal is output until the switching element is turned on / off. Hereinafter, differences from the operation signal control example 1 will be described, and the same control contents as the operation signal control example 1 are denoted by the same reference numerals as those in FIG.

  The operation signal control example 3 is different from the operation signal control example 1 in that the timing for changing the operation signal is determined in consideration of the time lag in the operation signal processing of FIG. 2 (step S12). As an example of the timing, the threshold α corresponding to the time lag period is used, and the process branches depending on whether or not the difference value Δd is equal to or less than the threshold α (in parentheses in step S13).

  Even if the operation signal transmitted to the switching element Q2 is changed after detecting that the difference value Δd becomes zero as in the operation signal control example 1, the switching element Q2 actually falls from on to off. There will be a little time lag until the end. Therefore, in the operation signal control example 3, the operation signal is changed early in consideration of the time lag so that the timing when the difference value Δd becomes zero coincides with the timing when the switching element Q2 falls from on to off.

  Similarly to the operation signal control example 1, since the switching elements Q2 and Q3 are simultaneously turned on from time t13, the secondary voltage Vs2 is output from the secondary terminal of the transformer Tr1, and the waveform value output from the integrated waveform output unit 22 W2 increases. When the difference value Δd decreases with this increase, the difference value Δd becomes equal to or less than the threshold value α at time t14 (YES in step S13 in FIG. 2). At this time, the operation signal of the switching element Q2 is changed (from on to off) (step S14 in FIG. 2), and input of the difference value Δd from the difference value detection unit 25 is stopped (step S15 in FIG. 2).

  The operation signal transmitted from the operation signal control unit 21 (specifically, the control circuit 21b) to the switching element Q2 by the control of the operation signal processing was originally scheduled to fall from on to off at time t15. Considering the time lag TL, it is forced to fall from on to off at time t32 (see arrow Dc). As shown in the figure, the operation signal is changed earlier than time t14 in the operation signal control example 1. The switching element Q2 that has received the operation signal falls from on to off at time t14 (see arrow Da). Thus, the time when the difference value Δd becomes zero coincides with the time when the switching element Q2 falls from on to off at time t14. Each cycle after the cycle Cy2 is similarly controlled. Therefore, no bias is generated in the transformer Tr1 in all cycles, and the bias in the transformer Tr1 can be suppressed in advance.

  Even when the switching element Q2 is started from OFF to ON, it is desirable to perform control to change the operation signal in consideration of the time lag TL. Although the operation signal to the switching element Q2 in the cycle Cy1 was originally scheduled to be turned on from off at time t31, it is turned on from off at time t30 in consideration of the time lag TL. Each cycle after cycle Cy2 is similarly controlled. By changing the operation signal in this way, the switching element Q2 rises from OFF to ON at times t31, t34, t37,. As a result, the duty ratio Dr2c (Dr2c <Dr2a) is obtained in each cycle after time t11. In other words, it can be regarded as control by changing the duty ratio. However, when the power supply start timing is time t11, the duty ratio Dr2c does not change in all cycles.

(Operation signal control example 4)
The operation signal control example 4 will be described with reference to FIGS. 6 and 7. This operation signal control example 4 is an example in which the operation signal to the switching element Q3 is changed on the basis of the cycle of the switching element Q1, similarly to the operation signal control example 2 described above. Hereinafter, differences from the operation signal control example 2 will be described, and the same control contents as those in the operation signal control example 2 are denoted by the same reference numerals as those in FIG.

  Regarding the operation signal transmitted to the switching element Q3, in the operation signal control example 2, the timing of falling from on to off is changed. On the other hand, the operation signal control example 4 is different in that the timing of starting from OFF to ON is changed.

  The second procedure example of the operation signal processing shown in the flowchart of FIG. 6 is executed instead of the procedure shown in FIG. The same processes as those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted. Steps in which FIG. 6 differs from FIG. 2 are steps S20 to S22. In step S20, the process branches depending on whether or not the difference value Δd input in step S11 in the previous execution is different from the difference value Δd input in step S11 in the current execution.

  If the difference value Δd is different between the previous time and the current time (YES in step S20), the operation signal processing is returned because the difference value Δd has not yet reached the maximum value Wx. On the other hand, if the difference value Δd is the same between the previous time and this time (NO in step S20), it means that the difference value Δd has reached the maximum value Wx. A period up to the present time (hereinafter referred to as “change period Dw1”) is specified [step S21].

  The control circuit 21b grasps in advance the timing for turning off the switching element Q2. Therefore, the timing for turning on the switching element Q3 from OFF is determined based on the change period specified in step S21, and the operation signal transmitted to the switching element Q3 is changed [step S22].

  According to the control of the operation signal processing, control is performed as shown in FIG. That is, the difference value Δd starts to change from time t11 when the switching element Q1 is turned on from off, and after time t12, the maximum value Wx is the same as the peak value Wp (NO in step S20 in FIG. 6). The period from time t11 to time t12 becomes the change period Dw1 (step S21 in FIG. 6). Since the change period Dw1 is specified, it is possible to easily calculate the time t40 that goes back by the change period Dw1 from the time t15 when the switching element Q2 is scheduled to fall from on to off. At time t40, the operation signal is changed so that the switching element Q3 rises from off to on (step S22 in FIG. 6).

  As a result of changing the operation signal in this manner, the switching element Q3 is delayed from the original time t13 to time t40 and is turned on from off (see arrow Dd). Accordingly, the switching elements Q2 and Q3 are simultaneously turned on during a period from time t40 to time t15, and the length of the period coincides with the change period Dw1. On the other hand, the waveform value W2 starts to increase from time t40, and reaches the maximum value Wx that is the same as the peak value Wp at time t15. Thus, the voltage time product of the secondary voltage Vs1 involving the switching elements Q1 and Q4 and the voltage time product of the secondary voltage Vs2 involving the switching elements Q2 and Q3 are substantially the same, and the period Cy1 is biased toward the transformer Tr1. Magnetism is not generated. Each cycle after the cycle Cy2 is similarly controlled. Therefore, no bias is generated in the transformer Tr1 in all cycles, and the bias in the transformer Tr1 can be suppressed in advance.

  The switching element Q3 that receives the change in the operation signal does not change on / off at times t13, t18,..., And is forcibly raised from off to on at times t40, t42,. As a result, the period up to time t11 was the duty ratio Dr3a, but in each period after time t11, the duty ratio Dr3c (Dr3c <Dr3a) is obtained. In other words, it can be regarded as control by changing the duty ratio. However, when the start timing of power supply from the power source Edc is time t11, the entire cycle does not change with the duty ratio Dr3c.

  Further, as shown in the operation signal control example 3 (FIG. 5), it is possible to control the operation signal transmitted to the switching element Q3 to change early in consideration of the time lag TL. According to this control, the time when the difference value Δd becomes zero can coincide with the time when the switching element Q2 falls from on to off. The voltage time product of the secondary voltage Vs1 involving the switching elements Q1 and Q4 and the voltage time product of the secondary voltage Vs2 involving the switching elements Q2 and Q3 can be made the same.

  According to the first embodiment described above, the following effects can be obtained. First, corresponding to claim 1, in the power conversion device 20, diodes D21 and D22 (two or more rectifiers) for rectifying an AC voltage (AC power) output from the secondary terminal of the transformer Tr1, and diodes D21 and D22. Integrated waveform output units 22 and 23 that output waveforms obtained by individually integrating DC voltages (DC power) rectified by, and two or more waveforms (integrated waveforms) output from the integrated waveform output units 22 and 23. Among the two or more waveforms output from the peak hold unit 24 that holds the peak value Wp applied to one waveform (waveform value W1) and the integrated waveform output units 22 and 23, the waveform other than the one waveform is excluded. A difference value detector 25 for detecting a difference value Δd between the waveform value W2 and the peak value Wp held by the peak hold unit 24, and a difference value Δd detected by the difference value detector 25. Therefore, it has the structure which has the operation signal control part 21 which controls the operation signal which operates a switching element (namely, one or both of switching element Q2, Q3) (refer FIGS. 1-7). According to this configuration, based on the difference value Δd (= Wp−W2), control is performed to change the operation signal transmitted to one or both of the switching elements Q2 and Q3. Can be deterred. By making each of the diodes D21 and D22 correspond to a positive / negative DC voltage, it is possible to prevent the bias of the transformer Tr1 in advance regardless of the positive / negative. Since it is only necessary to provide the diodes D21 and D22 corresponding to the positive and negative of the alternating voltage output from the secondary terminal of the transformer Tr1, without adding a circuit element to the current flow path, the cost of the entire apparatus can be suppressed. .

  Corresponding to claim 2, the operation signal control unit 21 operates on / off of one or both of the switching elements Q2 and Q3 (switching elements related to waveforms other than one waveform) based on the difference value Δd. (See FIGS. 2 to 7). According to this configuration, one or both of the switching elements Q2 and Q3 related to the output of the secondary voltage Vs2 are controlled, that is, the switching elements Q1 and Q4 related to the output of the secondary voltage Vs1 are operated. The operation signal to be changed is changed. When the waveform value W2 is controlled to be equal to the peak value Wp, the voltage time product of the secondary voltage Vs1 and the voltage time product of the secondary voltage Vs2 become substantially the same. Therefore, it is possible to reliably suppress the bias of the transformer Tr1.

  Corresponding to claim 3, when the difference value Δd reaches zero (numerical value “0”), the operation signal control unit 21 applies one or both of the switching elements Q2 and Q3 (the waveform excluding one waveform). The switching element is turned on / off (see FIGS. 2 and 3). According to this configuration, since the difference value Δd is controlled to be zero, that is, the waveform value W2 is equal to the peak value Wp, the voltage time product of the secondary voltage Vs1 and the voltage time product of the secondary voltage Vs2 are the same. Become. Therefore, it is possible to reliably suppress the bias of the transformer Tr1.

  Corresponding to claim 4, the operation signal control unit 21 considers the time lag TL from when the operation signal is output until one or both of the switching elements Q2, Q3 change to ON / OFF. Is output earlier by the time lag TL (see steps S12 and S14 in FIG. 2 and FIG. 3). According to this configuration, the operation signal control unit 21 outputs an operation signal for operating one or both of the switching elements Q2 and Q3 earlier by the period of the time lag TL. In this way, the operation signal is transmitted to one or both of the switching elements Q2 and Q3 in anticipation of the time lag TL, so that it is possible to more reliably suppress the demagnetization that may occur in the transformer Tr1.

  Corresponding to claim 5, the power supply system 10 having the power conversion device 20 includes a connection portion J for electrically connecting the output terminals of the diodes D11 and D12 (rectifying portions), and an alternating current component of the direct current voltage at the connection portion J. It was set as the structure which has the filter part 12 to reduce (refer FIG. 1). According to this configuration, it is possible to cope with positive and negative DC components while suppressing cost, and it is possible to suppress the bias of the transformer Tr1 without adding a circuit element to the current flow path.

[Embodiment 2]
The second embodiment is an example in which the magnetic bias of the transformer is suppressed in advance based on the power by voltage control, as in the first embodiment, and will be described with reference to FIG. A part of the configuration of the power supply system 10 including the power conversion device 20 is the same as that of the first embodiment. Therefore, in the second embodiment, the same elements as those used in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and contents different from the above-described first embodiment are described.

  The second embodiment is greatly different in that a transformer Tr2 is used instead of the transformer Tr1 (see FIG. 1) of the first embodiment. The transformer Tr1 used a type having at least three terminals as a secondary terminal together with a primary terminal. On the other hand, the transformer Tr2 is of the same type as the primary terminal and the secondary terminal, and does not have an intermediate terminal like the transformer Tr1. Note that a transformer having an intermediate terminal may be used as in the case of the transformer Tr1, but the intermediate terminal is not used.

  Along with the use of the transformer Tr2, rectifiers Db1, Db2, switches SW1, SW2, etc. are newly added. The rectifiers Db1, Db2, and the input side are connected in parallel to the secondary terminal of the transformer Tr2. The rectification unit Db1 also functions as the “connection unit J” and is provided in the power supply system 10. One terminal of the rectifying unit Db1 is connected to the capacitor C11 and the filter unit 12, and the other terminal is connected to the ground N. The rectifying unit Db2 is provided in the power conversion device 20. One terminal of the rectifying unit Db2 is connected to the integrated waveform output units 22 and 23, and the other terminal is similarly connected to the ground N. These rectifiers Db1 and Db2 are composed of diodes or the like, and have a function of rectifying the secondary voltage Vs3 (AC power) output to the secondary terminal of the transformer Tr2 into DC voltage (DC power), and are a half-wave rectifier circuit It does not matter if it is a full-wave rectifier circuit.

  The switches SW1 and SW2 are individually controlled to be turned on / off by the control circuit 21b. The switch SW1 switches whether to transmit the output of the integrated waveform output unit 23 (that is, the waveform value W1 of the secondary voltage Vs3 corresponding to the secondary voltage Vs1) to the peak hold unit 24. The switch SW2 switches whether to transmit the output of the integrated waveform output unit 22 (that is, the waveform value W2 of the secondary voltage Vs3 corresponding to the secondary voltage Vs2) to the difference value detection unit 25.

  For example, the switch SW1 is controlled to be turned on / off at the same timing as the switching element Q1 shown in FIGS. 3 to 7, and the switch SW2 is controlled to be turned on / off in a pattern opposite to that of the switch SW1. That is, the switch SW1 is turned on when detecting the waveform value W1 applied to the secondary voltage Vs3 corresponding to the secondary voltage Vs1 in the first embodiment. Similarly, when the waveform value W2 applied to the secondary voltage Vs3 corresponding to the secondary voltage Vs2 in the first embodiment is detected, the switch SW2 is turned on. Thus, the control circuit 21b controls the on / off of the switches SW1 and SW2, thereby realizing the operation signal control examples 1 to 4 (see FIGS. 3 to 7) described in the first embodiment.

  According to the second embodiment described above, since the operation signal control examples 1 to 4 (see FIGS. 3 to 7) described in the first embodiment can be realized, the embodiments respectively corresponding to claims 1 to 5. 1 is obtained. That is, it is possible to suppress the bias of the transformer Tr2.

  The power supply system 10 having the power conversion device 20 corresponding to claim 6 also reduces the AC component of the DC voltage (DC power) output from the rectifying unit Db1 including the function of the connecting unit J and the rectifying unit Db1. And a filter unit 12 (see FIG. 8). According to this configuration, it is possible to deal with positive and negative DC components while suppressing cost, and it is possible to suppress the bias of the transformer Tr2 without adding a circuit element to the current flow path.

[Other Embodiments]
In the above, although the form for implementing this invention was demonstrated according to Embodiment 1, 2, this invention is not limited to the said form at all. In other words, various forms can be implemented without departing from the scope of the present invention. For example, you may implement | achieve each form shown below.

  In the first and second embodiments described above, the waveform value W1 of the waveform output from the integrated waveform output unit 23 is received based on the secondary voltage Vs1 (or the secondary voltage Vs3 corresponding to the secondary voltage Vs1), and the waveform A peak hold unit 24 that holds and outputs a peak value Wp that is the maximum value of the value W1 is provided (see FIGS. 1 and 8). Instead of the peak hold unit 24, the waveform value W2 of the waveform output from the integrated waveform output unit 22 based on the secondary voltage Vs2 (or the secondary voltage Vs3 corresponding to the secondary voltage Vs2) is received, and the waveform value W2 A peak hold unit 26 that holds and outputs the peak value Wp that is the maximum value of the peak value Wp may be provided (see the two-dot chain line shown in FIGS. 1 and 8). In this case, when the output of the peak value Wp is input to the plus terminal of the difference value detecting unit 25 and the waveform value W1 output from the integrated waveform output unit 23 is input to the minus terminal of the difference value detecting unit 25, FIG. A change with time similar to 7 is obtained. However, the waveform value W1 and the waveform value W2 shown in FIGS. In other words, the peak value Wp for either one of the waveform value W1 and the waveform value W2 may be input to the plus terminal of the difference value detecting unit 25, and the other may be input to the minus terminal of the difference value detecting unit 25. The waveforms (waveform values) input to the plus terminal and the minus terminal of the difference value detection unit 25 may be reversed. In this configuration, the waveform values W1 and W2 and the peak value Wp shown in FIGS. 3 to 7 are only negative values (−dx). Regardless of the configuration, since the control for changing the operation signal transmitted to the target switching element is performed based on the difference value Δd, it is possible to suppress the bias of the transformers Tr1 and Tr2.

  In the first and second embodiments described above, the power conversion unit that converts DC voltage (DC power) to AC voltage (AC power) in the power conversion device 20 is a full bridge using the switching elements Q1 to Q4. It comprised (refer FIG. 1, FIG. 8). Instead of this form, a power conversion unit that reduces the number of switching elements may be configured. For example, the half bridge method shown in FIG. 9A or the push-pull method shown in FIG. 9B may be used. In the half-bridge configuration shown in FIG. 9A, a capacitor C2 is used instead of the switching element Q2, and a capacitor C4 is used instead of the switching element Q4. Although not shown, a plurality of single forward systems, flyback systems, etc. (for example, 2 or 4) may be used and connected to the primary terminal side of the transformers Tr1 and Tr2. Since only the configuration of the power conversion unit connected to the primary terminal side of the transformers Tr1 and Tr2 is different, the same effects as those of the first and second embodiments can be obtained.

  In the first and second embodiments described above, the operation signal of the switching element Q1 is used as a reference, and the operation signals of the switching elements Q2 and Q3 are changed (operation signal control examples 1 to 4; FIGS. reference). Instead of this form, the operation signals of the switching elements Q2 and Q3 may be changed based on the operation signals of the switching element Q4. In this configuration, for example, in FIG. 3 to FIG. 7, one cycle is from time t12 to time t17, from time t17 to time t1c. Similarly to the first and second embodiments, one of the switching elements Q2 and Q3 may be used as a reference, and one or both of the switching elements Q1 and Q4 may be changed. Since only the reference operation signal is different, the same operational effects as those of the first and second embodiments can be obtained.

  In the first and second embodiments described above, RC circuits including resistors and capacitors are applied as the integrated waveform output units 22 and 23 (see FIGS. 1 and 8). Instead of this form, for example, an integration circuit using an operational amplifier may be used. Even if an integration circuit is used, waveform values W1 and W2 that are integrated over time and become an integrated waveform can be output, so that the same operational effects as those of the first and second embodiments can be obtained.

  In the first and second embodiments described above, the LC circuit including the reactor L12 and the capacitor C12 is applied as the filter unit 12 (low-pass filter) (see FIGS. 1 and 8). Instead of (or in addition to) this form, a filter unit having another configuration capable of removing a high-frequency component of a DC voltage (DC power) may be applied. For example, an RC circuit composed of a resistor and a capacitor, an active low-pass filter using an operational amplifier, and the like are applicable. Not only analog filters such as these, but digital filters may also be used. Since any filter unit can remove a high-frequency component (AC component) of a DC voltage (DC power), the same effect as in the first and second embodiments can be obtained.

  In the first and second embodiments described above, the N-channel MOSFET is used for the switching elements Q1 to Q4 (see FIGS. 1, 8, and 9). Instead of this form, another switching element may be used. Examples of other switching elements include FETs (specifically, P-channel MOSFETs, JFETs, MESFETs, etc.), IGBTs, GTOs, power transistors, and the like. Regardless of which switching element is used, a power converter that converts a DC voltage (DC power) into an AC voltage (AC power) can be configured, so that the same effects as those of the first and second embodiments can be obtained.

  In the first and second embodiments described above, the integrated waveforms of the secondary voltages Vs1, Vs2, and the secondary voltage Vs3 are obtained based on the DC voltage (DC power) supplied from the power source Edc, and a difference is obtained within one cycle. When the value Δd becomes 0, an operation signal for operating one or both of the switching elements Q2 and Q3 is changed (see FIGS. 1 to 8). That is, it applied about the electric power by voltage control. It can replace with this form and can also apply to the electric power by current control. In this case, the power conversion device 20 is supplied with a direct current (direct current power) from the power source Edc, converts it into an alternating current (alternating current power), and outputs it. Since the method for converting the circuit configuration related to the constant voltage source to the circuit configuration related to the constant current source is well known, the circuit configurations shown in FIGS. 1 and 8 can be converted in the same manner. However, since phase lag is generated by the transformers Tr1 and Tr2, it is desirable to control the switching elements Q1 to Q4 in consideration of the phase lag. Therefore, the same effects as those of the first and second embodiments described above can be obtained for the electric power by the current control.

  In the first and second embodiments described above, the difference value Δd corresponding to the period of the time lag TL is set as the threshold value α, and the threshold value α is not changed (see steps S12 and S13 in FIG. 2 and FIG. 5). Instead of this form, the numerical value of the threshold value α may be changed. For example, at initialization (for example, at the start of power supply or at reset), an appropriate numerical value is set for the threshold value α. Performing), a configuration in which the control is performed so that the difference value Δd becomes zero at the timing when the operation signal of the target switching element is changed. Even if the period of the time lag TL is expanded or contracted due to the influence of the external environment (especially external noise) or aging deterioration, the operation signal of the target switching element can be finely changed at the timing when the difference value Δd becomes zero. it can. Therefore, the same effect as Embodiments 1 and 2 described above can be obtained.

  In the first and second embodiments described above, the switching element Q2 is controlled to change the operation signal in consideration of the time lag TL (see steps S12 and S13 in FIG. 2 and FIG. 5). In addition to this form, a configuration may be adopted in which one or more switching elements among the switching elements Q1, Q3, and Q4 are controlled to change the operation signal in consideration of a time lag as in the case of the switching element Q2. Furthermore, it is desirable to perform a control for changing the operation signal in consideration of a time lag for each individual switching element in consideration of individual differences between the switching elements Q1 to Q4. In this way, the control delay due to the time lag can be eliminated, and the bias magnetism of the transformers Tr1 and Tr2 can be suppressed without fail.

  In the first and second embodiments described above, the time lag TL is configured as “a period from when the operation signal is output until the on / off of the switching elements Q1 to Q4 changes” (steps S12 and S13 in FIG. 5). Instead of this form, it is desirable to further include a “period from when the difference value Δd is detected until the operation signal is output”. Although it is a short period, it can be controlled more precisely so that the difference value Δd becomes zero at the timing when the operation signal of the target switching element is changed. Therefore, the control delay due to the time lag can be further eliminated, and the bias magnetism of the transformers Tr1 and Tr2 can be suppressed without fail.

DESCRIPTION OF SYMBOLS 10 Power supply system 12 Filter part 20 Power converter 21 Operation signal control part 21a Drive circuit 21b Control circuit 22,23 Integrated waveform output part 24 Deviation amount detection part 30 Output apparatus D21, D22 Diode (rectifier part)
Db1, Db2 Rectifier J Connection Q1, Q2, Q3, Q4 Switching element TL Time lag Tr1, Tr2 Transformer W1, W2 Waveform value Wp Peak value Δd Difference value

Claims (5)

In a power converter including at least a switching element that performs switching based on an operation signal, and a transformer that electrically connects the switching element to a primary terminal,
Two or more rectifiers for rectifying AC power output from the secondary terminal of the transformer;
An integrated waveform output unit that outputs a waveform obtained by individually integrating DC power rectified by the two or more rectifying units;
Among two or more waveforms output from the integrated waveform output unit, a peak hold unit that holds a peak value applied to one waveform, and
A differential value detection unit that detects a differential value between a waveform value of the waveform excluding the one waveform among two or more waveforms output from the integrated waveform output unit and a peak value held by the peak hold unit When,
An operation signal control unit that controls an operation signal for operating the switching element based on the difference value detected by the difference value detection unit;
The power converter characterized by having.   The power converter according to claim 1, wherein the operation signal control unit operates on / off of the switching element related to a waveform excluding the one waveform based on the difference value.   The power converter according to claim 2, wherein the operation signal control unit operates on / off of the switching element related to a waveform excluding the one waveform when the difference value reaches zero.   In consideration of a time lag from when the operation signal is output until the switching element is turned on / off, the operation signal control unit outputs the operation signal at a timing earlier than the time lag. The power conversion device according to claim 1, wherein the power conversion device is a power conversion device. It has the power converter device according to any one of claims 1 to 4,
A connection part for electrically connecting output terminals of the two or more rectification parts;
A filter unit for reducing an AC component of DC power in the connection unit;
A power supply system comprising:

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