JP2017139867A - DC-DC converter device and power storage system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC-DC converter device that inexpensively implements both of a safety margin and conversion efficiency and is capable of sufficiently improving a characteristic.SOLUTION: A device includes a control circuit 13 including an efficiency improvement control unit 14 including: comparators 17a, 17b that in order to make a target value be used so that conversion efficiency is maintained so as to increase within a safety operation region depending on a result of comparing current I, Iat different positions of an isolation transformer T with output current Ifrom a DC-DC converter 11, variably generate switching setting time Δt for control timing corresponding to a variation in a circuit parameter caused by leakage inductance of the transformer T; and logical circuits 18a, 18b that when being set S at set time of main control timing generated by a pulse conversion unit 16, outputs a control operation instruction signal showing an efficiency improvement control timing instruction value at the time Δt during which comparator output is reset R and held, to provide the signal for the pulse conversion unit 16 generating a switching operation control signal to switching/rectification circuits 12a, 12b.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a DC-DC converter device having an insulating function that employs a switching method with excellent conversion efficiency to convert a DC voltage into another DC voltage and output it, and a power storage system using the DC-DC converter device.

  In recent years, in order to respond to the power demand in consideration of the preservation of the global environment, charging is performed with the built-in storage battery unit during normal power supply to the load device of the commercial AC power supply, and when the power supply is stopped, An electric storage system such as an uninterruptible power supply of constant commercial type that has a function of discharging and backing up power supply for a long time has attracted attention.

  In such a general-purpose configuration of a power storage system, a DC-DC converter that converts a DC voltage into another DC voltage and outputs it after using a storage battery unit as a battery is used, and the input side (primary side) of the insulation transformer is used. ) And the output side (secondary side) are provided with a switching circuit for performing rectification processing by switching operations of a plurality of switching elements, and the control circuit controls these switching circuits in synchronism to control power. The conversion efficiency is improved. Incidentally, the configuration including the DC-DC converter and the control circuit for controlling the switching circuit here may be called a DC-DC converter device.

  However, in general, the DC-DC converter has a very large circuit parameter fluctuation range due to the leakage inductance of the insulation transformer. Therefore, when designing to achieve stable operation, the maximum conversion efficiency cannot be achieved and the power conversion characteristics are reduced. There is a drawback that it cannot be set uniformly with a good yield. Therefore, in order to reduce the fluctuation range of the circuit parameters, it is necessary to add a special transformer or a component with an inductance larger than the leakage inductance. However, such measures cannot avoid an increase in cost, and the switching loss is reduced. Since it becomes the factor which increases, it is unpreferable practically.

  Incidentally, as a well-known technique for improving the efficiency of power conversion in consideration of circuit parameters due to the leakage inductance of such an isolation transformer, a switching element having a fast switching characteristic and a relatively slow reverse recovery characteristic of the body diode is used. “Bidirectional DC-DC converter” (see Patent Document 1) having a small and highly efficient insulation function that reduces the switching loss and reduces the influence of the relatively slow reverse recovery characteristic of the body diode. “Power supply apparatus and control method of power supply apparatus” (see Patent Document 2) including a full-bridge inverter that can be reduced in size at low cost.

Japanese Patent No. 5587382 Japanese Patent No. 5557731

  In the techniques according to Patent Document 1 and Patent Document 2 described above, the circuit parameter due to the leakage inductance of the isolation transformer is set as a fixed value, and the input voltage or output voltage and output current (or input current) (or input current) in the DC-DC converter is controlled by program control. The control of the switching circuit is performed based on the switching setting time of the control timing calculated by the control circuit based on the detection result of the current.

If the switching setting time t here is specifically analyzed, for example, the input voltage or output voltage in the DC-DC converter is V, the output current is I _OUT , the minimum setting time is tmin, the leakage inductance is Lr, the transformer turns ratio. Is Nps, the safety factor is X, and the product of the multiplication of the leakage inductance Lr of the insulating transformer and the transformer turns ratio Nps by the safety factor X is α = [Lr · N _PS ] × X, t = [α Calculated with a relational expression of I _OUT / V] + tmin.

That is, the optimum value of the switching setting time t is proportional to the output current I _OUT (or the input current I _IN ) and the leakage inductance Lr, and is inversely proportional to the input voltage or the output voltage V. Is stored as a fixed value circuit parameter, and the switching setting time t according to the state of the circuit operation is calculated using the fixed value circuit parameter. As a result, a certain degree of conversion efficiency can be maintained while ensuring a safety margin.

  However, according to the control using the switching set time t, it is necessary to secure a safety margin within the safe operation region against the fluctuation of the circuit parameter, and in the vicinity of the boundary between the safe operation region and the dangerous operation region. Since it shows a variation in performance over a wide range within the safe operation area below the optimum value corresponding to a certain maximum conversion efficiency point, in fact, sufficient improvement in characteristics with both a safety margin and conversion efficiency has been achieved. There is no problem. Even if a safety margin is ensured in this way, if it is a DC-DC converter device that is not excellent in conversion efficiency, it is difficult to apply to a power storage system in terms of performance, and it is often NG. In short, in the case of a DC-DC converter device of a type that performs control using a switching set time t calculated using a fixed value circuit parameter, a yield that makes it suitable in terms of performance to be applied to a power storage system in manufacturing. However, there is a need for improvement in order to suppress variation in performance and improve conversion efficiency.

  The present invention has been made to solve such problems, and the technical problem thereof is a DC-DC converter device capable of achieving a sufficient improvement in characteristics while achieving both a safety margin and conversion efficiency at a low cost. It is to provide a power storage system using the same.

  In order to solve the above technical problem, a first means of the present invention includes a first switching circuit for performing rectification processing according to switching operations of a plurality of switching elements on an input side and an output side of an insulating transformer. A DC-DC converter provided with a second switching circuit, and in order to improve the conversion efficiency of the DC-DC converter, the DC-DC converter has a second function depending on the input current or input voltage, or the output current or output voltage. In a DC-DC converter device comprising: a control circuit that generates a pulse width modulated switching operation control signal for controlling switching operations of a plurality of switching elements in one switching circuit and a second switching circuit; The control circuit is used to convert the current or current at different points in the isolation transformer to a DC-DC converter. The conversion efficiency of the DC-DC converter becomes a predetermined target value that rises and is maintained in the safe operating range in accordance with the result of comparison with the input current or input voltage, or the output current or output voltage in the converter. In addition, a comparator that automatically and variably generates a control timing switching setting time corresponding to a change in circuit parameters due to leakage inductance of the insulation transformer, and a main control timing setting time generated in the circuit are set, A control operation indicating the efficiency improvement control timing command value at the variable switching setting time, which is reset at the variable switching setting time from the comparator and reset and held when the output of the comparator is set. A logic circuit that outputs a command signal and generates a switching operation control signal. And features.

  The second means of the present invention includes an AC / DC converter, a first unidirectional DC-DC converter, and a second unidirectional DC-DC that convert alternating current into direct current between a commercial power source and a load to be supplied with power. A converter and a DC / AC converter that converts direct current to alternating current are connected in series in this order, and a battery is connected to the wire between the first unidirectional DC-DC converter and the second unidirectional DC-DC converter. In the continuous inverter type power storage system configured as described above, the DC-DC converter device is used for at least one of the first unidirectional DC-DC converter and the second unidirectional DC-DC converter. Features.

  The third means of the present invention includes an AC / DC converter that converts AC to DC for an electric wire connected between a commercial power supply and a load to be supplied with power, a first unidirectional DC-DC converter, a second A unidirectional DC-DC converter and a DC / AC converter for converting direct current to alternating current are connected in parallel in this order, and between the first unidirectional DC-DC converter and the second unidirectional DC-DC converter. A battery is connected to the electric wire and the power supply system from the commercial power source and the discharge power supply system from the battery are switched between the output side of the DC / AC converter and the input side of the load. In an always-commercial unidirectional power storage system configured with a changeover switch, there are few first unidirectional DC-DC converters and second unidirectional DC-DC converters. Characterized in that the well is configured with the DC-DC converter device to one.

  According to a fourth means of the present invention, a bidirectional inverter, a bidirectional DC-DC converter, and a battery are connected in this order to an electric wire connected between a commercial power source and a load to be supplied with power. In a commercial bi-directional power storage system configured by interposing a relay for preventing reverse power flow on the electric wire on the side, using the DC-DC converter device as a bi-directional inverter And

  According to the present invention, with the above-described configuration, it is possible to achieve a sufficient improvement in characteristics that achieves both a safety margin and conversion efficiency at low cost. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is the general | schematic functional block diagram which showed the basic composition of the DC-DC converter apparatus which concerns on a well-known technique. It is the general | schematic functional block diagram which showed the basic composition of the DC-DC converter apparatus which concerns on the Example of this invention. 1 and the DC-DC converter apparatus shown in FIG. 2 and the DC-DC converter apparatus shown in FIG. 2 in relation to the control setting and the conversion efficiency, and the relationship between the switching setting time and the current value with respect to the conversion efficiency. It is a fluctuation characteristic figure of the circuit parameter illustrated. It is the figure which showed the equivalent circuit of the DC-DC converter in the DC-DC converter apparatus shown in FIG. 2 shows waveforms of various processing signals during conversion operation including rectification processing by controlling the switching operation for the switching element of the switching / rectifying circuit provided in the DC-DC converter by the control circuit of the DC-DC converter device shown in FIG. It is a timing chart. 2 shows a part of the configuration of the pulse converter included in the control circuit of the DC-DC converter apparatus shown in FIG. 2 in comparison with the waveforms extracted from the various processing signals shown in FIG. 5 including a part of the efficiency improvement controller. FIG. FIG. 2 is a diagram showing a detailed configuration of a pulse conversion unit included in the control circuit of the DC-DC converter device shown in FIG. 2 in comparison with waveforms extracted from various processing signals shown in FIG. 5 including a part of the efficiency improvement control unit. It is. FIG. 6 is a schematic diagram showing a state of a switching operation to the switching / rectifying circuit corresponding to the operation mode 1 in FIG. 5 according to the control circuit of the DC-DC converter device shown in FIG. 2. FIG. 6 is a schematic diagram showing a state of a switching operation to the switching / rectifying circuit corresponding to the operation mode 2 in FIG. 5 according to the control circuit of the DC-DC converter device shown in FIG. 2. It is the figure which showed schematic structure of the electrical storage system to which the DC-DC converter apparatus shown in FIG. 2 is applied, (a) is a figure regarding the electrical storage system of an always inverter system, (b) is an electrical storage system of an always commercial unidirectional system (C) is a figure regarding the always commercial bidirectional | two-way type electrical storage system.

  Hereinafter, examples of the DC-DC converter device of the present invention and a power storage system using the same will be described in detail with reference to the drawings.

  First, in order to facilitate understanding of the DC-DC converter device of the present invention and a power storage system using the same, a well-known DC-DC converter device will be described. FIG. 1 is a functional block diagram showing a basic configuration of a DC-DC converter device according to a known technique (configuration applicable to Patent Document 1 and Patent Document 2).

Referring to FIG. 1, a well-known DC-DC converter device includes a first switching / rectifying device for performing rectification processing according to switching operations of a plurality of switching elements on an input side and an output side of an isolation transformer T. A DC-DC converter 1 provided with a circuit 2a and a second switching / rectifying circuit 2b, an input voltage or an output voltage V in the DC-DC converter 1 in order to improve the conversion efficiency of the DC-DC converter 1, and Pulse width modulation for controlling the switching operation of a plurality of switching elements in the first switching / rectifier circuit 2a and the second switching / rectifier circuit 2b in accordance with the output current I _OUT (or may be the input current I _IN ) And a control circuit 3 for generating a PWM switching operation control signal. Incidentally, the notation “input / output voltage / current” in FIG. 1 generally indicates the input current or input voltage, or the output current or output voltage in the DC-DC converter 1 described above.

Among them, the control circuit 3 stably improves conversion efficiency based on the input voltage or output voltage V and the output current I _OUT (or may be the input current I _IN ) in the DC-DC converter 1 by program control. An efficiency improvement control unit 4 that calculates a control command value and a control timing of the control signal and outputs a control operation command signal indicating an efficiency improvement command value according to the switching set time t, an input voltage or an output voltage V in the DC-DC converter 1, and The control command value and the control timing are calculated so as to stabilize the output current or output voltage in the DC-DC converter 1 according to the output current I _OUT (or may be the input current I _IN ), and the stabilization control command value is indicated. Stabilization control unit 5 for outputting a control timing signal, and efficiency improvement control by switching set time t Switching operation for the first switching / rectifying circuit 2a and the second switching / rectifying circuit 2b, which are pulse-width-modulated PWM based on the control operation command signal indicating the command value and the control timing signal indicating the stabilization control command value And a pulse converter 6 for generating a control signal. Here, the efficiency improvement control unit 4 calculates the switching setting time t described above based on a relational expression of t = [α · I _OUT / V] + tmin (where α = [Lr · N _PS ] × X). .

By the way, the optimum value of the switching setting time t calculated by the efficiency improvement control unit 4 is proportional to the output current I _OUT (or input current I _IN ) and the leakage inductance Lr, and is inversely proportional to the input voltage or the output voltage V. Based on various parameters and their variations in design evaluation, the result of determining the set value of α (the value obtained by multiplying the leakage inductance Lr and transformer turns ratio Nps by the safety factor X) is held as a fixed value circuit parameter. The switching setting time t corresponding to the circuit operation status is calculated using the fixed circuit parameter. For this reason, in the DC-DC converter 1, it is necessary to secure a safety margin within the safe operation region with respect to fluctuations in circuit parameters, so that the maximum conversion efficiency point near the boundary between the safe operation region and the dangerous operation region is obtained. In the safe operation region below the optimum value corresponding to the above, there is a variation in performance over a wide range, so that there is a difficulty in that it is not possible to improve the characteristics while achieving both a safety margin and conversion efficiency. Therefore, in the DC-DC converter device of the present invention, as will be described below, the processing function of the efficiency improvement control unit 4 is changed and calculation using a fixed value circuit parameter is not performed, and the safety margin and conversion are performed at low cost. The purpose is to sufficiently improve the characteristics while achieving both efficiency.

  FIG. 2 is a functional block diagram showing the basic configuration of the DC-DC converter device according to the embodiment of the present invention.

Referring to FIG. 2, the DC-DC converter device according to the embodiment has a basic configuration and switching operations of a plurality of switching elements on the input side and the output side of the isolation transformer T, similarly to the configuration shown in FIG. 1. In order to improve the conversion efficiency of the DC-DC converter 11 provided with the first switching / rectifying circuit 12a and the second switching / rectifying circuit 12b for performing rectification processing according to The first switching / rectifying circuit 12a and the second switching / rectifying circuit 12b are configured in accordance with the output current I _OUT (input current I _IN , or input voltage or output voltage V) in the DC-DC converter 11. Generates a pulse width modulation PWM switching operation control signal for controlling the switching operation of the switching element And a control circuit 13 for performing the configuration.

However, the control circuit 13 here uses the current (or current) at different points in the isolation transformer T as the output current I _OUT (input current I _IN , input voltage or output voltage V) in the DC-DC converter 11. The circuit parameter according to the leakage inductance Lr of the insulation transformer T is set so that the conversion efficiency of the DC-DC converter 11 rises and is maintained in the safe operation range according to the result of comparison with A comparator that automatically and variably generates a switching set time Δt (indicating a variable increment with respect to the switching set time t) of the control timing corresponding to the fluctuation of the control timing, and a main control timing set time generated in the circuit Set S, reset R at a variable switching setting time Δt from the comparator, and set An efficiency improvement control unit 14 having a logic circuit that outputs a control operation command signal indicating an efficiency improvement control timing command value at a variable switching setting time Δt held when the output of the comparator is reset to R when S is performed; The control command value and the control timing are generated so that the output current I _OUT (the input current I _IN , or the input voltage or the output voltage V) in the DC-DC converter 1 is stable, and the stabilization control command value is indicated. A stabilization control unit 15 that outputs a control timing signal, and a control operation command that generates a set time of the main control timing and outputs it to the logic circuit, and indicates an efficiency improvement control timing command value by a variable switching set time Δt The first switching / rectifying circuit 2a and the second switching circuit are based on the signal and the control timing signal indicating the stabilization control command value. A pulse converter 16 for generating a pulse width modulated PWM by switching operation control signal for controlling the switching-on time of the switching element provided in the rectifying circuit 2b and off-time, configured with a.

Among them, in the case of the present embodiment, the efficiency improvement control unit 14 serves as a comparator for the current (or voltage) at a specific location of the isolation transformer T and the output current I _OUT (input current I) in the DC-DC converter 11. _IN , or an input voltage or an output voltage V), and a first comparator 17a that generates a first switching set time Δt1 that can be changed according to a result of comparison with the result of comparison with other than the specific portion in the isolation transformer T A second variable that can be varied in accordance with the result of comparing the current (or voltage) at the location and the output current I _OUT (input current I _IN , or input voltage or output voltage V) in the DC-DC converter 11. And a second comparator 17b for generating the switching set time Δt2. Further, as a logic circuit, set S is set by the set time of the main control timing generated by pulse conversion unit 16, and reset R is set by variable first switching set time Δt1 from first comparator 17a. In addition, when set S, the control operation command signal indicating the efficiency improvement control timing command value at the variable first switching setting time Δt1 held by setting the output of the first comparator 17a to the reset R is the first. Similarly to the first logic circuit 18a by RS-FF (flip-flop) that outputs a switching element (which corresponds to a switching element H0 described later) having a trigger function in the switching and rectifying circuit 12a of the above and the set S. It is set by the set time of the main control timing generated by the pulse converter 16, and the reset R is sent from the second comparator 17b. When the set S is set, and the output of the second comparator 17b is set to the reset R, the efficiency at the variable second switching set time Δt2 is maintained. An RS-FF (flip-flop) that outputs a control operation command signal indicating an improved control timing command value as a control target of a switching element (which corresponds to a switching element S0 described later) having a trigger function in the second switching / rectifying circuit 12b And a second logic circuit 18b.

Incidentally, the current at a particular location of the above-described insulation transformer T can be exemplified a case where the transformer current I _T through input side of the switching element and the insulating transformer T included in the first switching rectifier circuit 12a. On the other hand, the voltage at a specific location of the insulation transformer T is the input-side transformer voltage applied to each switching element and the insulation transformer T included in the first switching / rectifier circuit 12a on the input side of the insulation transformer T. The case can be illustrated. Also, the current at a location other than the specific location of the insulation transformer T flows through each switching element included in the second switching / rectifier circuit 12b and the output side of the insulation transformer T and is stored in the capacitor Cc described later, Or the case where it is the capacitor _| condenser electric current _ICc which is discharged from the capacitor | condenser Cc and flows through each switching element can be illustrated. On the other hand, the voltage at a location other than the specific location of the insulation transformer T is an output that is transformed and applied to each switching element and capacitor Cc included in the second switching / rectifier circuit 12b on the output side of the insulation transformer T. The case where it is a side transformer voltage can be illustrated. The DC-DC converter apparatus according to the embodiment, the transformer current I _T current on the input side at a particular location of the isolation transformer T, as shown in FIG. 2, current at a point other than the specific portion of the insulating transformer T _{Is the} output-side capacitor current _ICc .

  FIG. 3 shows a switching setting time and a current value with respect to the conversion efficiency shown in order to compare the control contents and the conversion efficiency in the DC-DC converter device shown in FIG. 1 and the DC-DC converter device shown in FIG. FIG. 6 is a fluctuation characteristic diagram of circuit parameters exemplified in relation to

  Referring to FIG. 3, in the well-known DC-DC converter device, the efficiency improvement control unit 4 of the control circuit 3 performs control using the switching set time t calculated using a fixed circuit parameter. Since it is necessary to secure a safety margin within the safe operation region where the current value is low with respect to the circuit parameter variation (variation) typ related to the transformer T, there is a difference between the safe operation region and the dangerous operation region where the current value is high. The figure shows how the characteristics (performance) vary over a wide range within the safe operation region below the optimum value corresponding to the maximum conversion efficiency point when it is near the boundary. Further, in the conventional control method, the switching setting time t is also short and shows a state where the setting is performed with a fixed value.

On the other hand, in the DC-DC converter apparatus according to the embodiment, the comparators 17a and 17b in the efficiency improvement control unit 14 of the control circuit 13 are not used with fixed circuit parameters and the transformer current I on the input side of the isolation transformer T is used. _The control timing corresponding to the fluctuation of the circuit parameter due to the leakage inductance Lr of the insulation transformer T can be changed according to the result of comparing _T and the output side capacitor current I _Cc with the output current I _OUT in the DC-DC converter 11. Switching setting time Δt (first switching setting time Δt1, second switching setting time Δt2) is automatically generated, and the first switching / rectifying circuit 2a and the second switching / rectifying circuit will be described later. Controls the ON time and OFF time of the switching operation of each switching element in 2b That since subjected to generation of a switching operation control signals to implement the commutation process, it shows how the conversion efficiency in the DC-DC converter 11 is maintained at a predetermined target value to increase in safe operating area. Although it can be said that the target value here is preferably the optimum value corresponding to the highest conversion efficiency point, in terms of practical use, if the safety margin is estimated, even if the current value is less than the optimum value, the conversion efficiency is high. In order to improve, it may be a somewhat low value. Further, in the control method of the present invention, the variable switching setting time Δt (first switching setting time Δt1, second switching setting time Δt2) is longer than the fixed switching setting time t in the case of the conventional control method. It shows a state where a long variable value is set. As a result, the DC-DC converter device according to the embodiment can achieve a sufficient characteristic improvement that satisfies both a safety margin and conversion efficiency at a low cost (details will be described later). In FIG. 3, the fluctuation characteristic diagram of the circuit parameters related to the insulation transformer T is shown in relation to the switching setting time t, Δt (Δt1, Δt2) and the current value with respect to the conversion efficiency. The fluctuation characteristics of the circuit parameters in relation to the values show almost the same tendency, so this may be referred to.

  FIG. 4 is a diagram illustrating an equivalent circuit of the DC-DC converter 11 in the DC-DC converter device according to the embodiment.

  Referring to FIG. 4, the first switching / rectifying circuit 12a uses a total of five switching elements H0, H1, H2, H3, and H4 composed of N-channel field effect transistors (FETs) and insulates them from the power source. The winding T is connected to the winding coil on the input side of the transformer T, and the leakage coil of the leakage inductance Lr and the capacitor C due to the parasitic capacitance of the charge are provided in the lead-out portion of the winding coil. On the detailed configuration, the drain terminals of the switching elements H0, H1, H2, H3, and H4 are directed to the positive electrode side of the DC power supply, and the source terminals of the switching elements H0, H1, H2, H3, and H4 are connected to the negative electrode side of the DC power supply. Is a connection pattern in which switching elements H0, H1, and H2 are connected in series to a DC power source, and the drain terminal of the switching element H3 is connected between the source terminal of the switching element H0 and the drain terminal of the switching element H1. A winding coil on the input side of the insulating transformer T so as to connect between the source terminal of the switching element H3 and the drain terminal of the switching element H4 and between the source terminal of the switching element H1 and the drain terminal of the switching element H2, and Leakage inductor having a leakage inductance Lr of the lead portion and Capacitor C is connected.

The second switching / rectifying circuit 12b uses switching elements S0, S1, S2, S3, and S4 including a total of five N-channel field effect transistors (FETs), which are output on the output side of the load and the isolation transformer T. winding coil and a capacitor Cc of, and connected to the C _OUT, and has a configuration in which the smoothing inductor of the smoothing inductance L of the insulating transformer T is Motasa between the drain terminal and the capacitor C _OUT of the switching element S3. In the detailed configuration, it is a connection pattern in which the drain terminals of the switching elements S0, S1, S2, S3, and S4 are directed to the grounded capacitor Cc, and switching is performed between the source terminal of the switching element S3 and the drain terminal of the switching element S4. A winding coil on the output side of the isolation transformer T is connected so as to connect between the source terminal of the element S1 and the drain terminal of the switching element S2, and the source terminal of the switching element S2 and the source terminal of the switching element S4 are grounded. A capacitor _{COUT, a} load, and a smoothing inductor having a smoothing inductance L are connected between the drain terminal of the switching element S3 and the source terminal of the switching element S4.

  FIG. 5 shows switching elements H0, H1, H2, H3, H4 of the first switching / rectifying circuit 12a provided in the DC-DC converter 11 by the control circuit 13 of the DC-DC converter apparatus according to the embodiment and the second It is a timing chart which shows the waveform of various processing signals at the time of conversion operation including the rectification processing which controls switching operation to switching elements S0, S1, S2, S3, and S4 of switching / rectifier circuit 12b.

Referring to FIG. 5, here, switching elements H0, H1, H2, H3, H4 of the first switching / rectifying circuit 12a and switching elements S0, S1, S2, S3, S4 of the second switching / rectifying circuit 12b are referred to. Together with the waveform of the switching operation control signal (applied to the voltage value) sent to the gate terminal at, and the transformer current I _T , the output current I _OUT in the DC-DC converter 11, and the plus and minus waveforms of the capacitor current I _Cc In addition, the operation mode 0 to the operation mode 7 included in one cycle are repeated in the subsequent cycles.

First, the operation mode 0 to the operation mode 7 included in one cycle will be described. The stabilization control unit 15 in the control circuit 13 shown in FIG. 2 outputs the output current I _OUT (or the input current I _IN , the input voltage, or the output voltage V For the control indicating the command value obtained as a result of calculating the time of the operation mode 1 that changes after the initial operation start time corresponding to the operation mode 0 of the initial state every cycle so that it may be stable) The timing signal is output to the pulse converter 16. In the pulse converter 16, the switching elements H1, H2, H3, H4 in the first switching / rectifying circuit 12a and the switching elements S1, S2, in the second switching / rectifying circuit 12b based on the command value of the control timing signal, A switching operation control signal for controlling the on time and the off time for S3 and S4 is generated. At this time, the efficiency improvement control unit 14 pulses a control operation command signal indicating the efficiency improvement control timing command value at the second switching set time Δt2 that can be varied by the logic circuit 18b in synchronization with the start time of the operation mode 1. The switching element S0 is turned on by the switching operation control signal generated by pulse width modulation PWM generated by the pulse conversion unit 16 and the control operation command signal is output to the conversion unit 16, and after the operation mode 1 is completed, the switching element S0 Continue to turn on. As a result, a state of the operation mode 2 in which the transformer current _IT changes from an increase to a decrease in a plus waveform by the circuit operation is obtained. In the operation mode 2, but the capacitor current I _Cc is increased in proportion to the decrease in the transformer current I _T, the turns ratio of the capacitor current I variation of _Cc insulating transformer T in this case, the leakage inductance Lr or the input, It strongly depends on parameters such as voltage or output voltage V. The peak value of the waveform of the capacitor current I _Cc at the time when the operation mode 2 ends is a reference current I _REF less than that value generated from the output current (average value) I _OUT . Further, when the switching element S0 is turned off, the state of the operation mode 3 that the transformer current I _T is circulated through the switching elements H1, H3. Further, the switching elements S2 and S3 are turned off in the time from the operation mode 0 to the operation mode 2 by the switching operation control signal generated by the pulse converter 16, and the switching elements S2 and S3 are turned on when the operation mode 3 is reached. The switching elements S1 and S4 are kept in the ON state throughout the operation mode 0 to operation mode 3. The logic circuit 18a in the efficiency improvement control unit 14 outputs a control operation command signal indicating an efficiency improvement control timing command value at the first switching set time Δt1 that can be varied through the time of these operation modes 0 to 4. Output to the pulse converter 16, and the pulse converter 16 turns on the switching element H 0 over the entire operation mode 0 to operation mode 3 by the switching operation control signal generated by pulse width modulation PWM of the control operation command signal. Maintain state. In addition, the switching element H4 is turned on in the time of the operation mode 0 and the operation mode 1 by the switching operation control signal generated by the pulse conversion unit 16, and the switching element H4 is turned off in the operation mode 2 and later. After turning off in the time of operation mode 0 and operation mode 1, it is turned on in the time after operation mode 2, and the switching element H1 is kept in the on state throughout the time of operation mode 0 to operation mode 3. The switching element H2 is maintained in the state of being turned off throughout the time from the operation mode 0 to the operation mode 3.

Thereafter, the stabilization control unit 15 similarly corresponds to the next operation mode 4 for each period so that the output current I _OUT (or the input current I _IN , the input voltage, or the output voltage V) may be stabilized. The control timing signal indicating the command value obtained as a result of calculating the time of the operation mode 5 that is shifted after the initial operation start time is output to the pulse converter 16. In the pulse converter 16, the switching elements H1, H2, H3, H4 in the first switching / rectifying circuit 12a and the switching elements S1, S2, in the second switching / rectifying circuit 12b based on the command value of the control timing signal, A switching operation control signal for controlling the on time and the off time for S3 and S4 is generated. At this time, the efficiency improvement control unit 14 pulses the control operation command signal indicating the efficiency improvement control timing command value at the second switching set time Δt2 that can be varied by the logic circuit 18b in synchronization with the start time of the operation mode 5. The switching element S0 is turned on by the switching operation control signal generated by the pulse conversion unit 16 and output by the pulse converter 16 by performing pulse width modulation PWM on the control operation command signal, and after the operation mode 5 ends, the switching element S0 Continue to turn on. As a result, a state of the operation mode 6 in which the transformer current _IT is changed from decreasing to increasing in a minus waveform having a shape in which the plus waveform transformer current _IT is inverted by the circuit operation is obtained. In the operation mode 6, although the capacitor current I _Cc is increased in proportion to the increment of the transformer current I _T, turns ratio of the isolation transformer T also the amount of change in capacitor current I _Cc Here, leakage inductance Lr, or It strongly depends on parameters such as input voltage or output voltage V. Further, when the switching element S0 is turned off, the state of the operation mode 7 transformer current I _T is circulated through the switching elements H2, H4. Since the circulating current in the operation mode 3 and the operation mode 7 described above has an optimum value suitable for circuit operation, it is desirable to keep the optimum value. Further, the switching elements S1 and S4 are turned off in the time of the operation mode 4 to the operation mode 6 by the switching operation control signal generated by the pulse converter 16, and the switching elements S1 and S4 are turned on when the operation mode 7 is reached. The state where the switching elements S2 and S3 are continuously turned on throughout the operation mode 4 to the operation mode 7 is maintained. The logic circuit 18a in the efficiency improvement control unit 14 controls the control operation command signal indicating the efficiency improvement control timing command value at the first switching set time Δt1 that can be varied with respect to the times of these operation modes 4 to 7. Is output to the pulse converter 16, and the switching element H0 is continuously turned on in the operation mode 4 to the operation mode 7 by the switching operation control signal generated by the pulse converter 16 by performing pulse width modulation PWM on the control operation command signal. Maintain the state Further, the switching element H4 is turned off in the time of the operation mode 4 and the operation mode 5 by the switching operation control signal generated by the pulse converter 16, and the switching element H4 is turned on after the operation mode 6 and the switching element H3 is turned on. Is turned on in the time of operation mode 4 and operation mode 5, then turned off in the time after operation mode 5, and the switching element H1 is maintained in the state of being turned off throughout the time of operation mode 4 to operation mode 7. The switching element H2 is kept turned on throughout the operation mode 4 to operation mode 7.

By the way, the predetermined target value at which the conversion efficiency described with reference to FIG. 3 rises and is maintained in the safe operation region is the first logic circuit 18a at the initial operation start time in the control circuit 13 described above. The first switching is performed by the switching operation control signal obtained by performing the pulse width modulation PWM on the output of the control operation command signal indicating the efficiency improvement control timing command value at the variable first switching setting time Δt1 that is output. · operation mode 1 according to the positive waveform of a transformer current I _T indicated set by the stabilization controller 15 to the on state of the switching element H0 responsible for triggering function corresponding to the control target of the rectifier circuit 12a under the conditions was continued, The second logic circuit 18b is variable after the conversion operation of the isolation transformer T is started in the time of the operation mode 5 related to the negative waveform. The control operation command signal indicating the efficiency improvement control timing command value at the switching setting time Δt2 is transmitted to the pulse conversion unit 16, and the second switching operation control signal generated by the pulse width modulation PWM by the pulse conversion unit 16 is used for the second operation. switching rectifier circuit 12b next operation mode 2 that is automatically generated in the on state of the switching element S0 in the control object responsible for triggering by causing continued, to reduce the transformer current I _T in the operation mode 6 from an increase in the positive waveform In the negative waveform, when the transition is from a decrease to an increase in the negative waveform, the transformer current _IT is set to the first switching / rectifier circuit 12a in the continuous operation mode 3 and the operation mode 7 which are set by turning off the switching element S0. Circulates through predetermined switching elements (in operation mode 3, switching elements H1 and H3 Ri, the switching elements H2, H4 in the operation mode 7 may be indicators of optimum value of the circulating current applicable) when.

FIG. 6 is an excerpt of various processing signals shown in FIG. 5 including a part of the efficiency improvement control unit 14 and a part of the configuration of the pulse conversion unit 16 included in the control circuit 13 of the DC-DC converter apparatus according to the embodiment. It is the figure shown by contrasting with a waveform. However, in FIG. 6, the waveforms of the transformer current _IT and the output current I _OUT input to the comparator 17a in the efficiency improvement control unit 14 shown in FIG. 5 are omitted, and the minus of the capacitor current I _Cc is shown. In the waveform, the start timing of the operation mode 1 and the operation mode 5 is the set timing for the switching element S0, the operation mode 2 after the operation mode 1 is completed, and the start timing of the operation mode 6 after the operation mode 4 is the reset timing for the switching element H4. Show.

  Referring to FIG. 6, the pulse conversion unit 16 generates a clock oscillator 21 that oscillates and outputs a rectangular wave clock signal, and a set S timing signal that indicates the set time of the main control timing according to the rectangular wave of the clock signal. A timing generation unit 22 to be generated, a counter 23 that repeats counting in synchronization with the timing generation unit 22, a control timing signal that indicates a counted value from the counter 23 and a stabilization control command value from the stabilization control unit 15 A comparator group including comparators 27a and 27d for generating a reset R timing signal based on the result of the comparison, a timing signal for the set S from the timing generator 22 and a reset R from the comparator 27a RS-FF (Flicker) which outputs a control operation command signal for the switching element H1 based on the timing signal of RS-FF that outputs a control operation command signal for the switching element H4 based on the logic signal 28a by the flop) and the timing signal for set S from the timing generator 22 and the timing signal for reset R from the comparator 27d. And a logic circuit group including a logic circuit 28d (flip-flop).

The comparator 17b in the efficiency improvement control unit 14 includes a reference current I _REF proportional to an output current (average value) I _OUT that is less than the value generated from the capacitor current I _Cc and the output current (average value) I _OUT. Is input, and the logic circuit 18b controls the switching element S0 based on the timing signal for the set S from the timing generator 22 and the timing signal for the reset R from the comparator 17b. A control operation command signal indicating the efficiency improvement control timing command value at the switching set time Δt2 is output. When the logic circuit 18b receives the timing signal for the set S from the timing generation unit 22 in operation, the logic circuit 18b sets the output of the comparator 17b to reset R and outputs a control operation command signal for the switching element S0. Incidentally, for the comparator 17a in the efficiency improvement control unit 14 schematically shown, a reference current I proportional to an output current (average value) I _OUT less than that value generated from the transformer current _IT and the output current (average value) I _{OUT. REF} is input, and based on the timing signal for the set S from the timing generator 22 and the timing signal for the reset R from the comparator 17a, the logic circuit 18a can change the switching element H0 to be controlled. A control operation command signal indicating an efficiency improvement control timing command value at a switching setting time Δt1 of 1 is output. When the logic circuit 18a also receives a timing signal for the set S from the timing generator 22 in operation, the output of the comparator 17a is reset to R and a control operation command signal for the switching element H0 is output.

FIG. 7 shows waveforms extracted from various processing signals shown in FIG. 5 including a part of the efficiency improvement control unit 14 and the detailed configuration of the pulse conversion unit 16 included in the control circuit 13 of the DC-DC converter apparatus according to the embodiment. It is the figure shown in contrast with. However, in FIG. 7, the waveform of the output current I _OUT shown in FIG. 5 is omitted.

Referring to FIG. 7, the comparator group and the logic circuit group described with reference to FIG. 6 are the first switching / rectifying circuit 12a controlled by the comparator 17a and the logic circuit 18a in the efficiency improvement control unit 14. Switching element H0, and switching element H1, H2, H3, H4 and second switching / rectifying circuit in first switching / rectifying circuit 12a excluding switching element S0 controlled by comparator 17b and logic circuit 18b. The number corresponding to the switching elements S1, S2, S3, S4 in 12b is provided in the pulse converter 16. That is, in the pulse converter 16, switching operation control for the switching elements H1, H2, H3, H4 in the first switching / rectifying circuit 12a and the switching elements S1, S2, S3, S4 in the second switching / rectifying circuit 12b is performed. In order to generate a signal, the control timing signal indicating the stabilization control command value output from the stabilization control unit 15 in accordance with the output current I _OUT of the DC-DC converter 11 is compared with the count value from the counter 23. Comparators 27a, 27b, 27c, 27d, 27e, 27f, 27g, and 27h for outputting a reset R timing signal, a set S timing signal from the timing generator 22, and resets from the comparators 27a to 27h. First switching and rectification based on the timing signal for R, respectively RS-FF (flip-flop) that outputs a control operation command signal for controlling switching elements H1, H2, H3, H4 in the circuit 12a and switching elements S1, S2, S3, S4 in the second switching / rectifying circuit 12b ) Logic circuits 28a, 28b, 28c, 28d, 28e, 28f, 28g, and 28h.

In the waveform shown in FIG. 7, when the logic circuit 18b in the efficiency improvement control unit 14 receives the timing signal for the set S from the timing generation unit 22, the switching element S0 is turned on and the switching element S0 is turned on. period operation mode 1 performs a conversion operation in the isolation transformer T as the operation mode 5, shows that a value corresponding to the number of coil turns with respect to the transformer current I _T is the output current I _OUT. The stabilization control unit 15 calculates the time of the operation mode 1 and the operation mode 5 here so that the output current I _OUT (or the input current I _IN or the input voltage or the output voltage V may be stabilized) The command value is input to the pulse converter 16 as a control timing signal indicating the stabilization control command value. Therefore, the pulse converter 16 controls the switching elements H1, H2, H3, and H4 in the first switching / rectifying circuit 12a and the switching elements S1, S2, S3, and S4 in the second switching / rectifying circuit 12b. The control operation command signal is subjected to pulse width modulation PWM to generate a switching operation control signal for controlling the on time and the off time. When the period of the operation mode 1 and the operation mode 5 is completed, the switching elements H3 and H4 are turned on / off, and the switching element S0 maintains the on state. Output current _{I OUT} in this state is the sum of the transformer current _{I T} and the capacitor current _{I Cc.} Further, since the transformer current _IT starts to decrease, the capacitor current I _Cc increases, but the amount of change per time is strongly influenced by parameters such as the turn ratio of the isolation transformer T, the leakage inductance Lr, or the input voltage or the output voltage V. Dependent. Furthermore, the operation mode 3, the operation mode 7, as the circulating current in any suitable circuit operation in the comparator 17b of the efficiency control unit 14 is obtained in the positive waveform and the negative waveform of the transformer current I _T, the output current I _The reference current I _REF generated from _OUT is compared with the capacitor current I _Cc, and the logic circuits with the same timing (the logic circuits 28f and 28g that control the switching elements S2 and S3 in the plus waveform are applicable, and the minus waveform is in the minus waveform) The logic circuits 28e and 28h that control the switching elements S1 and S4 correspond to the reset R), and the switching element S0 is turned off. By performing such a switching operation, it depends on the circuit parameters (corresponding to the reset timing of the switching element S0) as indicated by the transition from the solid line state (1) to the dotted line state (2) of the waveform of the capacitor current I _Cc. Therefore, it is possible to automatically generate the times of the operation modes 2 and 6 so that any suitable circulating current can always be obtained.

  FIG. 8 shows the state of the switching operation to the switching / rectifying circuits 12a and 12b corresponding to the operation mode 1 with the waveforms of the various processing signals shown in FIG. 5 by the control circuit 13 in the DC-DC converter apparatus according to the embodiment. It is a schematic diagram.

Referring to FIG. 8, the control circuit 13 generates the control operation command signal indicating the efficiency improvement control timing command value generated by the efficiency improvement control unit 14 and the stabilization control unit 15 in the operation mode 1 described above. The control timing signal indicating the stabilization control command value is subjected to pulse width modulation PWM by the pulse conversion unit 16, and the switching elements H0, H1, H2, H3, H4 and the second switching circuit in the first switching / rectifier circuit 12a. A switching operation control signal for controlling on / off of the switching elements S0, S1, S2, S3, and S4 in the rectifier circuit 12b is output. Specifically, the switching elements H0, H1, and H4 in the first switching / rectifying circuit 12a are turned on, and the switching elements H2 and H3 are turned off, and at the same time, switching in the second switching / rectifying circuit 12b is performed. The elements S0, S1, and S4 are turned on, and the switching elements S2 and S3 are turned off to perform rectification processing. As a result, in the first switching / rectifying circuit 12a, the switching elements H0 and H1 and the capacitor C at the lead-out portion of the coil winding on the input side of the insulating transformer T and the leakage inductor of the leakage inductance Lr are passed to the switching element H4. It flows transformer current I _T in a direction. In the second switching / rectifying circuit 12b, the switching element S4 and the coil winding on the input side of the insulating transformer T are passed through the switching element S1 to the smoothing inductor of the smoothing inductance L of the insulating transformer T, and the capacitors C _OUT and An output current I _OUT directed to the load side flows, and a capacitor current I _Cc from the switching element S1 through the switching element S0 to the capacitor Cc flows. At this time, the capacitor C _OUT stores the charge of the output current I _OUT , and the capacitor Cc stores the charge of the capacitor current I _Cc .

  FIG. 9 shows the state of the switching operation to the switching / rectifying circuits 12a and 12b corresponding to the operation mode 2 with the waveforms of the various processing signals shown in FIG. 5 by the control circuit 13 in the DC-DC converter apparatus according to the embodiment. It is a schematic diagram.

Referring to FIG. 9, the control circuit 13 generates the control operation command signal indicating the efficiency improvement control timing command value similarly generated by the efficiency improvement control unit 14 and the stabilization control unit 15 in the operation mode 2 described above. The control timing signal indicating the stabilized control command value is subjected to pulse width modulation PWM by the pulse conversion unit 16 and the switching elements H0, H1, H2, H3, H4 and the second in the first switching / rectifier circuit 12a A switching operation control signal for controlling on / off of the switching elements S0, S1, S2, S3, and S4 in the switching / rectifying circuit 12b is output. Specifically, the switching elements H0, H1, and H3 in the first switching / rectifying circuit 12a are turned on and the switching elements H2 and H4 are turned off, and at the same time, the switching in the second switching / rectifying circuit 12b is performed. The elements S0, S1, and S4 are turned on, and the switching elements S2 and S3 are turned off to perform rectification processing. Thus, in the first switching / rectifying circuit 12a, the direction toward the switching element H3 through the switching element H1 and the capacitor C at the lead-out portion of the coil winding on the input side of the insulating transformer T and the leakage inductor of the leakage inductance Lr. It flows transformer current _{I T} to. In the second switching / rectifying circuit 12b, the switching element S4 and the coil winding on the input side of the insulating transformer T are passed through the switching element S1 to the smoothing inductor of the smoothing inductance L of the insulating transformer T, and the capacitors C _OUT and An output current I _OUT directed toward the load side flows, and a capacitor current I _Cc flows from the capacitor Cc through the switching element S0 toward the switching element S1. At this time, the electric charge of the output current I _OUT is stored in the capacitor C _OUT, and the electric charge of the capacitor current I _Cc is discharged from the capacitor Cc.

In the DC-DC converter device according to the embodiment, the control circuit 13 performs the switching operation according to the operation modes 0 to 7 described above in one cycle, and the same operation is repeated in the subsequent two cycles. but the switching element operating modes 5 and 6 in the operation mode 3 and the negative waveform transformer current I _T of the operation modes 1 and 2 as a pretreatment operation is circulated through the switching elements H1, H3 plus waveform as a preliminary processing operation H2 In the operation mode 7 that circulates through H4, the time of the circulating current excellent in smoothness on the waveform is kept long throughout the entire period, and the first switching and rectifying circuit 12a of the DC-DC converter 11 and the second Because the rectification process in the switching / rectifier circuit 12b of No. 2 is performed stably, the efficiency of power conversion can be improved. The In particular, in the DC-DC converter device according to the embodiment, the comparators 17a and 17b in the efficiency improvement control unit 14 in the control circuit 13 have the transformer current IT on the input side of the isolation transformer _T and the capacitor current _ICc on the output side. Is converted to the output current I _{OUT in} the DC-DC converter 11 so that the conversion efficiency of the DC-DC converter 11 becomes a predetermined target value that is increased and maintained in the safe operation region. The first switching setting time Δt1 and the second switching setting time Δt2 of the control timing corresponding to the fluctuation of the circuit parameter due to the leakage inductance Lr of the insulating transformer T are generated automatically and variably. Control operation command signal based on the first switching set time Δt1 from the logic circuit 18a connected to 17a The switching operation control signal generated by the pulse width modulation PWM maintains the switching element H0 serving as the trigger function in the first switching / rectifying circuit 12a in the on state, while the first from the logic circuit 18b connected to the comparator 17b. The switching operation control signal generated by pulse width modulation PWM of the control operation command signal based on the switching setting time Δt2 of 2 is used to control on / off of the switching element S0 that performs the trigger function in the second switching / rectifier circuit 12b. The other switching elements H1, H2, H3, H4 in the first switching / rectifying circuit 12a and the other switching elements S1, S2, S3, S4 in the second switching / rectifying circuit 12b are switched on and off, respectively. Control by operation control signal As a result, the rectification process can be performed accurately at the time of the conversion operation, so that the characteristics can be sufficiently improved at a low cost while achieving both the safety margin and the conversion efficiency. That is, it can be said that the DC-DC converter device according to the embodiment has a control function for performing the automatic adaptive switching operation.

  By the way, as an example of typical equipment to which the DC-DC converter device according to the embodiment is applied, there is a power storage system using a commercial power source. This power storage system is classified according to the circuit configuration attached to the battery that supplies discharge power to the load to be supplied with power, and is called a constant inverter system, a constantly commercial unidirectional system, or a constantly commercial bidirectional system It has been known.

  FIG. 10 is a diagram illustrating a schematic configuration of a power storage system to which the DC-DC converter device according to the embodiment is applied. FIG. 10 (a) is a diagram related to a constant inverter type power storage system, and FIG. FIG. 5C is a diagram related to a commercial unidirectional power storage system, and FIG. 8C is a diagram related to a commercial bidirectional power storage system.

  Referring to FIG. 10 (a), an always-inverted storage system is an AC / DC converter that converts alternating current (AC) into direct current (DC) between a commercial power source and a load, and a first unidirectional DC- A DC converter, a second unidirectional DC-DC converter, a DC / AC converter that converts direct current (DC) to alternating current (AC) are connected in series in this order, and the first unidirectional DC-DC converter and the second The battery is connected to the electric wire between the unidirectional DC-DC converters. Therefore, if the DC-DC converter device according to the embodiment is used for at least one of the first unidirectional DC-DC converter and the second unidirectional DC-DC converter in the continuous inverter type power storage system, it is safest and safe. In order to maintain the conversion efficiency, it is possible to improve the charge / discharge function in the battery as a commercial type uninterruptible power supply (UPS).

  Referring to FIG. 10 (b), the always-universal unidirectional power storage system uses an AC / DC converter, a first unidirectional DC-DC for an electric wire connecting a commercial power source and a load. A converter, a second unidirectional DC-DC converter, and a DC / AC converter are connected in parallel in this order, and a battery is connected to an electric wire between the first unidirectional DC-DC converter and the second unidirectional DC-DC converter. And a changeover switch for switching between a power supply system from a commercial power supply and a discharge power supply system from a battery is provided between the output side of the DC / AC converter and the input side of the load. . Therefore, if the DC-DC converter device according to the embodiment is used also for at least one of the first unidirectional DC-DC converter and the second unidirectional DC-DC converter in the always commercial unidirectional power storage system. Similarly, in order to safely maintain the maximum conversion efficiency, it is possible to improve the charge / discharge function in the battery as a commercial type uninterruptible power supply (UPS).

  Further, referring to FIG. 10 (c), the always-on commercial bi-directional power storage system includes a bi-directional inverter, bi-directional DC-DC converter, and battery for the electric wire connecting the commercial power source and the load. In addition to connecting in this order, a relay for preventing a reverse power flow is interposed on the commercial power supply side electric wire. Incidentally, the relay here is normally on, and is turned off when the inverter is operating such as a power failure. However, it is necessary to keep the relay on in order to continue the power supply to the load when the system fails. Therefore, with respect to the bidirectional DC-DC converter in this always-on commercial bidirectional type power storage system, if the DC-DC converter device according to the embodiment is used, in order to safely maintain the maximum conversion efficiency, It is possible to improve the charge / discharge function in a battery as a type of uninterruptible power supply (UPS).

  The DC-DC converter device of the present invention can be applied to an electric / communication / information processing apparatus in addition to being applied to a power storage system such as the above-described constant commercial type uninterruptible power supply (UPS).

1, 10 DC-DC converters 2a, 2b, 12a, 12b Switching / rectifying circuit 3, 13 Control circuit 4, 14 Efficiency improvement control unit 5, 15 Stabilization control unit 6, 16 Pulse conversion unit 17a, 17b, 27a-27h Comparator 18a, 18b, 28a-28h Logic circuit (RS-FF)
21 Clock Oscillator 22 Timing Generator 23 Counter T Isolation Transformer

Claims (7)

A DC-DC converter provided with a first switching circuit and a second switching circuit for performing rectification processing in accordance with switching operations of a plurality of switching elements on the input side and output side of the isolation transformer; -In order to improve the conversion efficiency of the DC converter, the plurality of the first switching circuit and the second switching circuit according to the input current or input voltage or the output current or output voltage of the DC-DC converter In a DC-DC converter apparatus comprising: a control circuit that generates a pulse width modulated switching operation control signal for controlling a switching operation of a switching element;
The control circuit is configured to determine whether the current or current at different points in the isolation transformer is compared with the input current or the input voltage, or the output current or the output voltage in the DC-DC converter. The switching setting time of the control timing corresponding to the fluctuation of the circuit parameter due to the leakage inductance of the insulation transformer is automatically set so that the conversion efficiency of the converter becomes a predetermined target value that is raised and maintained within the safe operation range. A comparator that is variably generated and set at the set time of the main control timing generated in the circuit, reset at a variable set switching time from the comparator, and when set, An efficiency control controller with the variable switching setting time held with the output reset. DC-DC converter apparatus characterized by comprising: a logic circuit, a which outputs a control operation command signal indicating the timing command value subjected to the generation of the switching operation control signal. The DC-DC converter apparatus according to claim 1,
The comparator generates a first switching setting time variable according to a result of comparing the output current or the output voltage in the DC-DC converter with a current or voltage at a specific location of the isolation transformer. Second switching that is variable according to a result of comparing the output current or the output voltage of the first comparator and the DC-DC converter with the current or voltage at a location other than the specific location of the isolation transformer. A second comparator for generating a set time;
The logic circuit sets a set with a set time of the main control timing, sets a reset with the variable first switching set time from the first comparator, and sets the first when set. A switching element that takes a trigger function in the first switching circuit, and outputs a control operation command signal indicating an efficiency improvement control timing command value at the variable first switching setting time held by resetting the output of the comparator of the first switching circuit; A first logic circuit to be output as a control target, a set is set with the set time of the main control timing, a reset is set with the variable second switching set time from the second comparator, and When set, the efficiency of the variable second switching setting time held by resetting the output of the second comparator. A second logic circuit for outputting a switching element as a control object responsible for triggering a control operation command signal indicating the control timing command value of the second switching circuits, DC-DC converter apparatus, comprising the. The DC-DC converter device according to claim 2,
The current or voltage at the specific location of the isolation transformer is a plurality of switching elements included in the first switching circuit and a transformer current flowing through an input side of the isolation transformer, or a plurality of currents or voltages at an input side of the isolation transformer. Switching element and the input-side transformer voltage applied to the insulation transformer,
A current or voltage at a location other than the specific location of the isolation transformer flows through the output side of the plurality of switching elements and the isolation transformer included in the second switching circuit and is stored by a capacitor, or A capacitor current discharged from the capacitor and flowing through the plurality of switching elements, or an output-side transformer voltage transformed and applied to the plurality of switching elements and the capacitor on the output side of the isolation transformer -DC converter device. The DC-DC converter device according to claim 3,
The target value is determined by the control operation command signal indicating the efficiency improvement control timing command value at the first switching setting time at which the first logic circuit is variable at an initial operation start time in the control circuit. The second logic after the conversion operation of the isolation transformer is started in the time of the operation mode instructed and set under the condition that the ON state of the switching element responsible for the trigger function corresponding to the control target of the switching circuit is continued. An ON state of a switching element that is responsible for the trigger function corresponding to the control target of the second switching circuit by the control operation command signal indicating the efficiency improvement control timing command value at the second switching setting time that can be varied by the circuit In the next operation mode that is automatically generated by continuing In the negative waveform, when the transition from decrease to increase is made, the transformer current is set to the predetermined switching of the first switching circuit in the continuous operation mode set by turning off the switching element responsible for the trigger function. A DC-DC converter device characterized by showing an optimum value of a circulating current when circulating through an element. AC / DC converter that converts alternating current into direct current between a commercial power source and a load to be supplied with power, a first unidirectional DC-DC converter, a second unidirectional DC-DC converter, and a DC that converts direct current into alternating current / AC converters are connected in series in this order, and a continuous inverter system configured by connecting a battery to the wire between the first unidirectional DC-DC converter and the second unidirectional DC-DC converter In power storage systems,
The DC-DC converter device according to any one of claims 1 to 4, wherein the first unidirectional DC-DC converter and the second unidirectional DC-DC converter are configured using at least one of the first unidirectional DC-DC converter and the second unidirectional DC-DC converter. A featured power storage system. AC / DC converter, first unidirectional DC-DC converter, second unidirectional DC-DC converter, DC that converts AC to DC for electric wires connected between the commercial power supply and the load to be supplied with power Are connected in parallel in this order, and a battery is connected to the wire between the first unidirectional DC-DC converter and the second unidirectional DC-DC converter, Always configured by providing a changeover switch for switching between a power supply system from the commercial power supply and a discharge power supply system from the battery between the output side of the DC / AC converter and the input side of the load. In a commercial unidirectional power storage system,
The DC-DC converter device according to any one of claims 1 to 4, wherein the first unidirectional DC-DC converter and the second unidirectional DC-DC converter are configured using at least one of the first unidirectional DC-DC converter and the second unidirectional DC-DC converter. A featured power storage system. A bidirectional inverter, bidirectional DC-DC converter, and battery are connected in this order to the electric wire connected between the commercial power supply and the load to be supplied with power, and reverse power flow is prevented in the electric wire on the commercial power supply side. In a regular commercial bidirectional type power storage system configured by interposing a relay for
A power storage system comprising the bidirectional inverter using the DC-DC converter device according to any one of claims 1 to 4.