JP2020150701A - Bidirectional DC-DC converter - Google Patents

Abstract

To provide a compact bidirectional DC-DC converter in which two cells or circuit elements between which electrical energy is transferred are not electrically connected, and a transformer or the like is not used.SOLUTION: The converter of the present invention includes two sets of circuits that include each input/output terminal pairs, a capacitor, and two switching means which are connected in series, in which the positive electrode sides and the negative electrode sides of the switching means on the negative electrode side in the two sets of the circuits are connected to each other via the capacitor and an inductor; the two switching means of each circuit are switched between a conductive state and a cut-off state in opposite phases to each other, at a predetermined cycle; and the state of the switching means is controlled so that after the switching means on the positive electrode side of the circuit on the transfer source side of the electrical energy has been switched to a conductive state, the switching means on the positive electrode side of the circuit on the transfer destination side of the electrical energy is switched to a conductive state, and so that the charging time period on the transfer destination side of the electrical energy is longer than the discharging time period.SELECTED DRAWING: Figure 1

Description

The present invention relates to a DC-DC converter that can be used for transmission of electrical energy between two DC power sources having different voltages, and more specifically, bidirectionally between two or more sets of input / output terminal pairs. The present invention relates to a bidirectional DC-DC converter capable of transmitting electrical energy.

Conventionally, cell balance and DC power supply voltage in systems that use multiple storage batteries (batteries, cells) such as power supply systems for vehicles, solar power generation systems, and household power storage systems that use fuel cells. Various configurations have been proposed and put into practical use as a bidirectional DC-DC converter used for conversion to a voltage required for operating a semiconductor device or other electronic components. For example, in Patent Document 1, Non-Patent Document 1, etc., one capacitor and two in series are connected between each of two sets of input / output terminal pairs to which the inductance and cathode of the power supply are connected. In a circuit in which switching means (switching means row) are connected in parallel, the terminals on the cathode side of the switching means on the cathode side of the switching means rows of the two sets of circuits are connected to each other, and the terminals on the anode side are connected to each other. A bidirectional DC-DC converter having a circuit configuration connected via an inductance is disclosed (in two sets of buck-boost chopper circuits, the inductance and the capacitor are shared, and the output side terminals are connected to each other. It has a structure.) Further, in Patent Document 2, Non-Patent Document 1, etc., one capacitor is connected in parallel between each of two sets of input / output terminal pairs to which the anode and cathode of the power supply are connected, and further, switching means. A circuit configuration is disclosed in which the bridge circuits of the above two sets of bridge circuits are inductively coupled to each other as a transformer coil between the diagonal points (the input / output terminal pairs are not connected).

International Publication No. 2007/108115 JP-A-2018-137894

"Technical Memo No.20160601 Bidirectional DC / DC Converter Various Circuit Methods" 2016 http://hirachi.cocolog-nifty.com/kh/files/29160601-1.pdf

In one application of the bidirectional DC-DC converter as described above, specifically, a plurality of cells (in the present specification, the term "cell" refers to electricity such as one battery or storage battery). Unless otherwise specified, any two cells in the group of cells consisting of a power source of the form of storing energy are converters (in the present specification, "converters"). , A bidirectional DC-DC converter.), Which are connected to each of the two sets of input / output terminal pairs, and transfer of electrical energy from one cell to the other is performed. At that time, in the case of a configuration in which two sets of input / output terminal pairs are electrically connected to each other in the circuit of the converter, the two cells connected to the input / output terminal pairs are also electrically connected. Therefore, in the circuit for connecting each cell to the input / output terminal pair of the converter, it is necessary to devise so that the two cells may be electrically connected. For example, when transferring electrical energy between two cells in a group of cells connected in series, the two cells cannot be electrically connected as they are, and those cells can be electrically connected from the cell group. Since it is necessary to insulate and then connect to the input / output terminal pair of the converter, a circuit for switching the connection for that purpose is required. On the other hand, in the case of a configuration in which the circuit lines between the diagonal points of the bridge circuit of the switching means connected between the two sets of input / output terminal pairs are inductively coupled as a transformer coil (isolated converter), the input / output Since the two cells connected to the terminal pair are electrically isolated, there is no need for a circuit that allows the two cells to be electrically connected as described above, but in the converter. Since a transformer having a large size and a bridge circuit of a switching means having a large number of parts are used as circuit elements, the configuration of the circuit becomes bulky and the available area may be limited. Therefore, it is advantageous if a converter that does not use a bulky circuit element such as a transformer and that requires as few components as possible in the converter can be configured. This also applies when electrical energy is transferred between a power source and a circuit element such as an electronic component, or between circuit elements.

Thus, one subject of the present invention is a bidirectional DC-DC converter having a circuit configuration in which two cells or other circuit elements to which electrical energy is transferred are not electrically connected, and It is an object of the present invention to provide a converter having a configuration in which a bulky circuit element such as a transformer is not used and the number of components in the converter can be as small as possible.

Also, in the case where two cells or other circuit elements for which electrical energy is transferred are connected to one of two sets of input / output terminal pairs of one converter, the cells or other circuit elements Where it is necessary to devise a circuit so that each can be connected to either of the input / output terminal pairs of the converter, which has only two sets, if the number of circuit elements that can be selected as two cells or other circuit elements increases. Indeed, the configuration of the circuit for connecting them to the input / output terminal pair of the converter tends to be complicated. On the other hand, if the number of input / output terminal pairs of the converter is more than two sets, that is, if the converter is capable of transmitting electrical energy from one input / output terminal pair to a plurality of input / output terminal pairs. It is advantageous because it makes it possible to simplify the circuit configuration for connecting two cells or other circuit elements for which electrical energy is transferred to the input / output terminal pair of the converter.

Thus, another object of the present invention is to provide a bidirectional DC-DC converter as described above, which has a configuration capable of transmitting electrical energy from one input / output terminal pair to a plurality of input / output terminal pairs. It is to be.

According to the present invention, the above problem is a bidirectional DC-DC converter device.
A first input / output terminal pair consisting of a positive electrode terminal and a negative electrode terminal connected to the anode and cathode of the first power supply or circuit element, respectively.
The first capacitor connected between the first input / output terminal pair and
The first and second switching means connected in series between the positive electrode terminal and the negative electrode terminal of the first input / output terminal pair are used, and both terminals are selectively electrically connected to each other. Switching means and
A second input / output terminal pair consisting of a positive electrode terminal and a negative electrode terminal connected to the anode and cathode of the second power supply or circuit element, respectively.
The second capacitor connected between the second input / output terminal pair and
A third and fourth switching means connected in series between the positive electrode terminal and the negative electrode terminal of the second input / output terminal pair are used, and both terminals are selectively electrically connected to each other. Including switching means
The second switching means and the positive electrode side terminal of the fourth switching means are connected via the first connecting capacitor, and the second switching means and the negative electrode side terminal of the fourth switching means are connected to each other. At least one first inductor is inserted in the connection line between the positive electrode side terminal and the negative electrode side terminal of the second switching means and the fourth switching means, which are connected via the second connecting capacitor. Being done
The states between both ends of the first switching means and the second switching means are switched between the conductive state and the cutoff state at predetermined cycles in opposite phases to each other.
The states between both ends of the third switching means and the fourth switching means are switched between the conductive state and the cutoff state in the predetermined cycle in opposite phases to each other.
When transferring electrical energy from the first power source or circuit element to the second power source or circuit element, the third switching means shuts off after the first switching means switches from the cutoff state to the conductive state. The time during which the first switching means and the third switching means are in the conductive state while switching from the state to the conductive state is such that the third switching means and the second switching means are in the conductive state. The state between both ends of the first to fourth switching means is controlled so as to be longer than the time of.
When transferring electrical energy from the second power source or circuit element to the first power source or circuit element, the first switching means shuts off after the third switching means switches from the cutoff state to the conductive state. The time during which the third switching means and the first switching means are in the conductive state while switching from the state to the conductive state is such that the first switching means and the fourth switching means are in the conductive state. It is achieved by an apparatus in which the state between both ends of the first to fourth switching means is controlled so as to be longer than the time.

In the above configuration, the "first power supply or circuit element" and the "second power supply or circuit element" are cells that are the transfer source or transfer destination of electrical energy in the converter device of the present embodiment. , A power source or a circuit element, and as described above, it may be an arbitrary power source such as a battery or a storage battery in a form for storing electric energy, a capacitor, an electronic component operating with a DC voltage, a circuit element such as a semiconductor device, and the like. When used as a transfer source for supplying electrical energy, it becomes a power source capable of outputting electric power. The "capacitor" and "inductor" may be capacitors and inductors commonly used in the art. The "coupled capacitor" may be a capacitor commonly used in the art. The term "coupled capacitor" is used to distinguish it from a capacitor connected between an input / output terminal pair. The first inductor may be inserted in either or both of the connection lines between the second switching means and the positive electrode side terminal and the negative electrode side terminal of the fourth switching means. A "switching means" is a current conduction state and a cutoff state between a pair of terminals in response to a control signal input to a control input terminal, such as a MOSFET or other transistor used in this field. It may be any means that can be switched. A control signal may be supplied to the control input terminal of the switching means from an external control device so that the state between both ends is switched in the above embodiment. With respect to switching between the conduction state and the cutoff state of the state between both ends of the switching means, the "predetermined period" is a period that may be arbitrarily set so that the transfer of electrical energy by the device is achieved. The term "opposite phase" means that in the first and second switching means or the third and fourth switching means, when one is in the conductive state, the other is in the cutoff state. .. In the control of the first to fourth switching means, the conditions to be satisfied are as described above, and the continuity in the first and second switching means or the third and fourth switching means. Switching between states and cutoff states may simply be performed at equal intervals, respectively. In that case, the state between both ends of the first to fourth switching means is the state of the first switching means when transferring electrical energy from the first power source or circuit element to the second power source or circuit element. The second switching means switches from the cut-off state to the conductive state when less than 1/4 of the length of the predetermined cycle elapses after switching from the cut-off state to the conductive state. When transferring electrical energy from a power source or circuit element to the first power source or circuit element, less than a quarter of the predetermined period length after the third switching means has switched from a cutoff state to a conductive state. Each of the first switching means may be controlled so as to switch from the cutoff state to the conductive state when the time has elapsed.

According to the above configuration, the first power supply or circuit element and the second power supply or the second power supply connected to the first and second input / output terminal pairs, as described in the description column of the later embodiment. Where electrical energy is transferred between the circuit elements, the first and second switching means are connected via a capacitor (connecting capacitor) between the second switching means and the fourth switching means. The input / output terminal pairs of the above are not electrically connected to each other, and the transfer of electric energy is achieved without the first power supply or circuit element and the second power supply or circuit element being electrically connected to each other. Therefore, even in the converter of the present invention, an electrical connection may be made between the first power supply or circuit element and the second power supply or circuit element for the transfer of electrical energy. It is not necessary to prepare a slightly complicated circuit configuration for this purpose. In the above configuration, unlike the conventional isolated converter, a transformer is not used to insulate the opposite side of the first input / output terminal and the opposite side of the second input / output terminal. Since the bridge circuit of the switching means is not configured on the opposite side of each input / output terminal, the size of the circuit is not bulky and the number of parts may be smaller.

Further, as a further aspect of the present embodiment, the above-mentioned bidirectional DC-DC converter device further comprises a positive electrode terminal and a negative electrode terminal connected to the anode and the cathode of the third power supply or circuit element, respectively. Input / output terminal pair and
With the third capacitor connected between the third input / output terminal pair,
The fifth and sixth switching means connected in series between the positive electrode terminal and the negative electrode terminal of the third input / output terminal pair are used, and both terminals are selectively electrically connected to each other. Including switching means
The second or fourth switching means and the positive electrode side terminal of the sixth switching means are connected via a third connecting capacitor, and the second or fourth switching means and the sixth switching means The negative electrode side terminals are connected via a fourth connecting capacitor, and the second or fourth switching means, the positive electrode side terminals of the sixth switching means, and the second or fourth switching means. At least one second inductor is inserted in the connection line between the negative electrode side terminals of the sixth switching means.
The states between both ends of the fifth switching means and the sixth switching means are switched between the conductive state and the cutoff state at predetermined cycles in opposite phases to each other.
When transferring electrical energy from the first or second power source or circuit element to the third power source or circuit element, after the first or third switching means is switched from the cutoff state to the conductive state. The time during which the fifth switching means is switched from the cutoff state to the conductive state and the first or third switching means and the fifth switching means are in the conductive state is the fifth switching. The state between both ends of the first to sixth switching means is controlled so that the time between the means and the second or fourth switching means is longer than the time during which the second or fourth switching means is in a conductive state.
When transferring electrical energy from the third power source or circuit element to the first or second power source or circuit element, the first or second switching means is switched from the cutoff state to the conductive state. The time during which the third switching means is switched from the cutoff state to the conductive state and the fifth switching means and the first or third switching means are in the conductive state is the second or third. The state between both ends of the first to sixth switching means may be controlled so as to be longer than the time during which the fourth switching means and the sixth switching means are in the conductive state. ..

In the configuration of the above aspect, the second inductor is between the second or fourth switching means and the positive electrode side terminal of the sixth switching means, and the second or fourth switching means and the sixth. It may be inserted into either one or both of the connection lines between the negative electrode side terminals of the switching means of. Further, by controlling the switching timing between the conduction state and the cutoff state in the first to sixth switching means as described above, a plurality of other power sources or a plurality of other power sources can be simultaneously supplied from any one power source or circuit element. It is also possible to transfer electrical energy to circuit elements. The switching between the conduction state and the cutoff state in the first to sixth switching means may be easily executed at equal intervals. In that case, the state between both ends of the first to sixth switching means is the first or second power source or circuit element when the electrical energy is transferred from the first or second power source or circuit element to the third power source or circuit element. After the first or third switching means is switched from the cut-off state to the conductive state, the fifth switching means is changed from the cut-off state to the conductive state when a time less than 1/4 of the length of the predetermined cycle elapses. When transferring electrical energy from the third power source or circuit element to the first or second power source or circuit element so as to switch, the fifth switching means switches from the cutoff state to the conductive state. Later, the first or third switching means are controlled so as to switch from the cutoff state to the conductive state when a time of less than 1/4 of the predetermined period length elapses. You can.

Alternatively, in the above device, a fourth input / output terminal pair composed of a positive electrode terminal and a negative electrode terminal connected to the anode and the cathode of the fourth power supply or circuit element, respectively,
The fourth capacitor connected between the fourth input / output terminal pair and
The seventh and eighth switching means connected in series between the positive electrode terminal and the negative electrode terminal of the fourth input / output terminal pair are used, and both terminals are selectively electrically connected to each other. Including switching means
The positive electrode terminal side of the sixth switching means and the eighth switching means is connected via a fifth connecting capacitor, and the negative electrode terminal side of the sixth switching means and the eighth switching means is the sixth. A connection line connected via a connecting capacitor and between the positive electrode side terminals of the sixth switching means and the eighth switching means and between the negative electrode side terminals of the sixth switching means and the eighth switching means. At least one third inductor is inserted in
The states between both ends of the seventh switching means and the eighth switching means are switched between the conductive state and the cutoff state at predetermined cycles in opposite phases.
When transferring electrical energy from the first, second or third power source or circuit element to the fourth power source or circuit element, the first, third or fifth switching means is released from the cutoff state. After switching to the conductive state, the seventh switching means is switched from the cutoff state to the conductive state, and the first, third or fifth switching means and the seventh switching means are in the conductive state. Both ends of the first to sixth switching means so that the time spent is longer than the time during which the seventh switching means and the second, fourth, or sixth switching means are in a conductive state. The state between is controlled,
When transferring electrical energy from the fourth power source or circuit element to the first, second or third power source or circuit element, the seventh switching means is switched from the cutoff state to the conductive state, and then the said. The first, third or fifth switching means is switched from the cutoff state to the conductive state, and the seventh switching means and the first, third or fifth switching means are in the conductive state. Between both ends of the first to sixth switching means so that the time spent is longer than the time during which the second, fourth or sixth switching means and the eighth switching means are in a conductive state. The state of may be controlled. That is, in such an embodiment, two bidirectional DC-DC converter devices having two input / output terminal pairs are connected.

In the configuration of the above aspect, the third inductor is between the second or fourth switching means and the positive electrode side terminal of the sixth switching means, and the second or fourth switching means and the sixth. It may be inserted into either one or both of the connection lines between the negative electrode side terminals of the switching means of. Further, by controlling the timing of switching between the conduction state and the cutoff state in the first to eighth switching means as described above, a plurality of other power sources or a plurality of other power sources can be simultaneously supplied from any one power source or circuit element. It is also possible to transfer electrical energy to circuit elements. It should be noted that the switching between the conduction state and the cutoff state in the first to eighth switching means may be easily executed at equal intervals. In that case, the state between both ends of the first to eighth switching means transfers electrical energy from the first, second or third power source or circuit element to the fourth power source or circuit element. Occasionally, after the first, third, or fifth switching means has switched from the cut-off state to the conductive state, the seventh switching means has elapsed less than a quarter of the length of the predetermined period. When transferring electrical energy from the fourth power source or circuit element to the first, second or third power source or circuit element so as to switch from the cutoff state to the conductive state, the seventh switching means. The first, third, or fifth switching means switches from the cut-off state to the conductive state when less than a quarter of the length of the predetermined cycle elapses after switching from the cut-off state to the conductive state. As such, each may be controlled.

According to a further aspect of the present embodiment described above, it is possible to transfer electrical energy from one input / output terminal pair to any one of a plurality of input / output terminal pairs. According to such a configuration, the power supply or circuit element to be the transfer source or transfer destination of the electric energy by the converter device may be connected to any one of three or more pairs of input / output terminals. Further, as described above, since the input / output terminal pairs are all connected by a connecting capacitor and are electrically insulated, from the power supply or the circuit element to the input / output terminal pair of the converter device. The circuit for switching connection of is simplified.

In the bidirectional DC-DC converter device of the present embodiment, an input / output terminal pair composed of a positive electrode terminal and a negative electrode terminal connected to an anode and a cathode of an arbitrary number of power supplies or circuit elements, respectively. , A capacitor connected between the input / output terminal pair and two switching means connected in series between the anode terminal and the negative electrode terminal of the input / output terminal pair, and select between both terminals respectively. In a configuration consisting of switching means that are electrically conductive with each other, the terminals on the positive electrode side of the switching means on the negative electrode terminal side are connected to each other via a connecting capacitor, and the terminals on the negative electrode side are connected to each other via a connecting capacitor, at least. One inductor is inserted so as to be connected in series with a connecting capacitor, and is connected to the above configuration, and conduction between both ends of the switching means is controlled in the same manner as described above. This may be configured to allow the transfer of electrical energy from one input / output terminal pair to any of any number of input / output terminal pairs. Thus, as the number of input / output terminal pairs increases, the circuit for switching connection from the power supply or circuit element to the input / output terminal pairs of the converter device is further simplified.

Thus, according to the invention described above, where the transfer of electrical energy is achieved in the converter without the two cells or other circuit elements being electrically connected, the two cells or other The input / output terminal pair to which the circuit elements are connected is connected by a capacitor instead of a transformer, and since there are few elements used in the circuit, both are more compact and simpler than before. A DC-DC converter is provided. Further, in a mode in which electrical energy can be transferred from one input / output terminal pair to any one of a plurality of input / output terminal pairs, a converter is used from the cell or other circuit element to which the electrical energy is transferred. It is expected that the circuit for switching the connection to the input / output terminal pair of the above will be simplified, the cost will be reduced, and the labor for configuring the circuit will be reduced.

Other objects and advantages of the present invention will be apparent from the following description of preferred embodiments of the present invention.

FIG. 1A is a diagram showing a circuit configuration of the first embodiment of the bidirectional DC-DC converter device according to the present invention. 1 (B) and 1 (C) show an example in which the insertion portion of the inductor L1 is changed in the configuration of FIG. 1 (A). FIG. 2A shows the time change of the ON / OFF state of the switching means when the electric energy is transferred from the V1 side to the V2 side in the circuit having the configuration of FIG. 1B. Shows the time change of the ON / OFF state of the switching means when the electric energy is transferred from the V2 side to the V1 side in the circuit having the configuration of FIG. 3 (A) to 3 (D) show the states of the switching means in the phases I to IV when the electric energy is transferred from the V1 side to the V2 side in the circuit having the configuration of FIG. 1, respectively. The direction of the voltage of the circuit element and the direction of the current flowing in the circuit are shown. 4 (A) to 4 (D) show the states of the switching means in the phases I to IV when the electric energy is transferred from the V2 side to the V1 side in the circuit having the configuration of FIG. 1, respectively. The direction of the voltage of the circuit element and the direction of the current flowing in the circuit are shown. FIG. 5 is a diagram showing a circuit configuration of a second embodiment of the bidirectional DC-DC converter device according to the present invention. FIG. 6 is a diagram showing a circuit configuration of a third embodiment of the bidirectional DC-DC converter device according to the present invention. FIG. 7A shows an example of a circuit configuration from each cell to the input / output terminals of the converter, which is required when the unidirectional DC-DC converter device is used as a cell balancer. FIG. 7B shows an example of a circuit configuration from each cell to the input / output terminals of the converter, which is required when the bidirectional DC-DC converter device is used as a cell balancer.

ot + n ... Input / output terminal (positive electrode) (n is a number code)
ot-n ... Input / output terminal (negative electrode)
Vn ... Power transmission / reception element (or its voltage)
Cn ... Capacitor Mn ... Switching means (MOSFET, etc.)
Sn ... Control input Cln ... Connected capacitor Ln ... Inductor

Some preferred embodiments of the present invention will be described in detail below with reference to the accompanying figures. In the figure, the same reference numerals indicate the same parts.

Advantages of Bidirectional DC-DC Converters With reference to FIG. 7, the DC-DC converters are used, for example, in order to make the cell balancer of the battery cell rows connected in series, that is, the charge amount uniform between the cells. Consider using it as a device that performs the transfer of electrical energy between. When the DC-DC converter is a unidirectional DC-DC converter, as shown in FIG. 7A, each cell also supplies electrical energy to another cell from another cell. It is necessary to prepare a switching circuit so that it can be connected to both the input side terminal and the output side terminal of the converter so that it can also be on the receiving side. Specifically, for example, as shown in the figure, each electrode of each cell is selectively connected to a switch Sin for selectively connecting the electrode to the input side terminal of the converter and to the side output terminal of the converter. Switch Sout is required respectively, and when the number of cells is n, 2n + 10 switches are used. On the other hand, when the DC-DC converter is a bidirectional DC-DC converter, as shown in FIG. 7B, the electrical energy in the converter is in the direction from the V1 side terminal to the V2 side terminal. Also, since it can be transferred from the terminal on the V2 side to the terminal on the V1 side, the electrode can be transferred to both poles of each cell in the cell row to one of the terminals in the converter, for example, the closer terminal. It suffices if a circuit for selectively connecting is provided. Specifically, for example, as shown in the figure, each electrode of each cell, switches S _A and S _B for selectively connecting the electrode converter input and output terminals V1 or V2 to either of are prepared, cells When the number is n, n + 10 switches are used. Therefore, the number of switches used in the bidirectional DC-DC converter is reduced as compared with the case of the unidirectional DC-DC converter, and the number of circuits for connecting each electrode to the terminal of the converter is also reduced. It is advantageous in that the configuration of can be simplified.

First Embodiment of a Bidirectional DC-DC Converter According to the Invention With reference to FIG. 1 (A), a first embodiment of a bidirectional DC-DC converter according to the present invention is a transfer source or transfer destination of electrical energy. Input / output terminal pairs ot + 1 (positive side) and ot-1 (negative side) to which the anode and cathode of one cell, power supply or other circuit element V1 (hereinafter referred to as "power transmission / reception element V1") are connected, respectively. (Side), capacitors C1 connected between input / output terminal pairs ot + 1, ot-1, and two switching means M1 and M2 connected in series at input / output terminal pairs ot + 1, ot-1, and electricity. Input / output terminal pair ot + 2 (positive side) to which the anode and cathode of the cell, power supply, or other circuit element V2 (hereinafter referred to as "power transmission / reception element V2"), which is the transfer destination or the other of the energy transfer source, are connected, respectively. ), Ot-2 (negative side), capacitor C2 connected by input / output terminal pair ot + 2, ot-2, and switching connected in series by input / output terminal pair ot + 2, ot-2. The means M3 and M4 are included, and the switching means M2 and the switching means M4 are connected to each other via the connecting capacitor Cl1 and the inductor L1 on the positive side thereof, and the connecting capacitor Cl2 is connected to the negative side thereof. It has a configuration connected via. The inductor L1 may be inserted in series with the connecting capacitor Cl2 in the connection line on the negative electrode side of the switching means M2 and the switching means M4 as shown in FIG. 1 (B), or as shown in FIG. 1 (C). , The connecting capacitors Cl1 and Cl2 may be inserted in series on both the positive electrode side and the negative electrode side of the switching means M2 and the switching means M4.

In such a configuration, the power transmission / reception elements V1 and V2 can supply or receive electric energy in addition to each cell in the row of cells (batteries, rechargeable batteries, etc.) connected in series as described above. It may be an arbitrary power source, a capacitor, a circuit element such as an electric machine or a semiconductor device that operates by consuming electric power. When the power transmission / reception elements V1 and V2 serve as a supply source (transfer source) of electric energy, they need to be cells, capacitors, or other power sources capable of supplying electric energy. Capacitors and articulated capacitors and inductors may be capacitors or inductors commonly used in the art. Each switching means has control input terminals (S1 to S4) such as MOSFETs, and switches between both terminals in response to a control signal given to each control input terminal from an external switching control device (SW control). Switching means or elements that selectively conduct with each other and may be those commonly used in the art.

In the above configuration, the switching means M1 and M2 on the power transmission / reception element V1 side and the switching means M3 and M4 on the power transmission / reception element V2 side have their respective states in FIG. 2 (A). , (B), switching between the conductive state (ON state) and the cutoff state (OFF state) at predetermined intervals which may be arbitrarily set in a predetermined period Ts in opposite phases to each other. As will be described in detail later, the timing of switching the ON / OFF state of the switching means on the transfer source side of the electric energy is earlier than that of the switching means on the transfer destination side of the electric energy. A control signal from the switching controller so that the phase of the ON / OFF state change advances, and the time during which charging occurs is longer than the time during which discharging occurs in the power transmission / reception element on the transfer destination side of electrical energy. Is configured to receive. The predetermined period Ts can be appropriately set so that the converter can appropriately perform the operation described below. In each control of the switching means M1 to M4, switching may be simply executed so that the ON state and the OFF state occur at equal intervals. In that case, the timing of switching the ON / OFF state of the switching means on the transfer source side of the electric energy is less than 1/4 of the length of the predetermined period Ts than the switching means on the transfer destination side of the electric energy. It is set to be faster by the time (dTs).

In the operation of the converter of FIG. 1, when transferring electrical energy from the power transmission / reception element V1 to the power transmission / reception element V2, the anode and cathode of the power transmission / reception element V1 are connected to the input / output terminal pairs ot + 1 and ot-1, respectively. Then, with the anode and cathode of the power transmission / reception element V2 connected to the input / output terminal pair ot + 2 and ot-2, respectively, the switching means M1 is switched to the ON state as shown in FIG. 2 (A). After that, the switching means M1 to M4 are controlled so that the switching means M3 is switched to the ON state when the time dTs elapses. When the switching means M1 to M4 are controlled so that the ON state and the OFF state between both ends of the switching means M1 to M4 occur at equal intervals, d is an arbitrary positive number satisfying <0.25. Further, V1> V2 is a condition in the voltage of the power transmission / reception element before the transfer of electric energy.

When the state of the switching means is controlled in this way, with reference to FIG. 3, in phase I (switching means M1 and M4 are ON, switching means M2 and M3 are OFF), FIG. 3 (A) shows. As depicted, the current i flows from the power transfer element V1 through the switching means M1, the inductor L1, the coupling capacitor Cl1, the switching means M4, and the coupling capacitor Cl2, and thus electrical energy is released from the power transmission / reception element V1. (Discharged state). At that time, the power transmission / reception element V2 is in a state in which charging / discharging is not performed (float state) because the anode is open. Next, when phase II (switching means M1 and M3 are ON and switching means M2 and M4 are OFF), as shown in FIG. 3B, the current i is transferred from the power transmission / reception element V1 to the switching means M1. Since the electric energy flows through the switching means M3, the power transmission / reception element V2, and the connection capacitor Cl2 via the inductor L1 and the connection capacitor Cl1, the electric energy emitted by the power transmission / reception element V1 (discharged state) charges the power transmission / reception element V2. Will be (charged). Then, when the phase III (switching means M2 and M3 are ON and switching means M1 and M4 are OFF), the current i is connected to the switching means M3 from the power transmission / reception element V2 as shown in FIG. 3C. Since the current flows through the capacitor Cl1, the inductor L1, the switching means M2, and the connecting capacitor Cl2, the power transmission / reception element V2 is in a state of releasing electric energy (discharge state). Thus, when the phase IV (switching means M2 and M4 are ON and switching means M1 and M3 are OFF), the power transmission / reception elements V1 and V2 are in a float state and the current i is as shown in FIG. 3 (D). However, the energy stored in the circuit is released through a loop including the switching means M2, the inductor L1, the connecting capacitor Cl1, the switching means M4, and the connecting capacitor Cl2. In the process from Phase I to Phase IV, the power transmission / reception element V1 is in a discharged state in Phase I and Phase II, and the power transmission / reception element V2 is in a charged state in Phase II and in Phase III. When the state of the switching means is controlled so that the time of phase II is longer than that of phase III, the power transmission / reception element V2 is charged, as is understood with reference to FIG. 2A. The time becomes longer than the time for discharging, and eventually, the electric energy released by the power transmitting and receiving element V1 is charged to the power transmitting and receiving element V2, and the transfer of the electric energy is achieved.

On the other hand, when transferring electrical energy from the power transmission / reception element V2 to the power transmission / reception element V1, the anode and cathode of the power transmission / reception element V1 are connected to the input / output terminal pairs ot + 1 and ot-1, respectively, and the input / output terminal pair With the anode and cathode of the power transmission / reception element V2 connected to ot + 2 and ot-2, respectively, as shown in FIG. 2B, after the switching means M3 is switched to the ON state, the time dTs The switching means M1 to M4 are controlled so that the switching means M1 is switched to the ON state after the lapse of time. Similar to the case of FIG. 3, when the switching means M1 to M4 are controlled so that the ON state and the OFF state between both ends of the switching means M1 to M4 occur at equal intervals, d sets <0.25. Any positive number that satisfies. In this case, V2> V1 is a condition for the voltage of the power transmission / reception element before the transfer of electric energy.

When the state of the switching means is controlled as shown in FIG. 2B, with reference to FIG. 4, in phase I (switching means M2 and M3 are ON, switching means M1 and M4 are OFF), As depicted in FIG. 4A, a current i flows from the power transmission / reception element V2 through the switching means M3, the coupling capacitor Cl1, the inductor L1, the switching means M2, and the connection capacitor Cl2, and thus the power transmission / reception element V2. Electric energy is released from (discharged state). At that time, the power transmission / reception element V1 is in a float state because the anode is open. Next, when the phase II (switching means M1 and M3 are ON and switching means M2 and M4 are OFF), the current i is transferred from the power transmission / reception element V2 to the switching means M3, as shown in FIG. 4 (B). The electric energy that flows through the switching means M1, the power transmission / reception element V1, and the connection capacitor Cl2 via the connection capacitor Cl1 and the inductor L1 and is released by the power transmission / reception element V2 (discharged state) is charged to the power transmission / reception element V1. Becomes (charged). Then, when the phase III (switching means M1 and M4 are ON and switching means M2 and M3 are OFF) is set, the current i is transferred from the power transmission / reception element V1 to the switching means M1 and the inductor as shown in FIG. 4C. Flowing through L1, the coupling capacitor Cl1, the switching means M4, and the connecting capacitor Cl2, the power transmission / reception element V2 is in a state of releasing electrical energy (discharged state), and the phase IV (switching means M2, M4 is ON, switching means M1, When M3 is OFF), as shown in FIG. 4D, the power transmission / reception elements V1 and V2 are in a float state, and the current i is the coupling capacitor Cl1, the inductor L1, the switching means M2, the coupling capacitor Cl2 and It flows through a loop composed of the switching means M4, and the energy stored in the circuit is released. In the process from Phase I to Phase IV, the power transmission / reception element V2 is in a discharged state in Phase I and Phase II, and the power transmission / reception element V1 is in a charged state in Phase II and in Phase III. When the state of the switching means is controlled so that the time of phase II is longer than that of phase III, the power transmission / reception element V1 is charged, as is understood with reference to FIG. 2 (B). The time becomes longer than the time for discharging, and eventually, the electric energy released by the power transmitting and receiving element V2 is charged to the power transmitting and receiving element V1, and the transfer of the electric energy is achieved.

Thus, in the above converter, only by changing the ON / OFF switching phase of the switching means on the power transmission / reception element V1 side and the power transmission / reception element V2 side, the electric energy from the power transmission / reception element V1 to the power transmission / reception element V2. And vice versa, as described in connection with FIG. 7, of the circuit from the power transfer element to which the electrical energy is transferred to the two sets of input / output terminal pairs of the converter. The configuration is simplified. Further, in the above configuration, in the phase II, the power transmission / reception element V1 and the power transmission / reception element V2 are simultaneously charged or discharged by the converter, but the power transmission / reception element V1 side and the power transmission / reception element V2 side. The switching means M2 and M4 of the above are connected at both positive and negative poles via the connecting capacitors Cl1 and Cl2, and the power transmission / reception element V1 and the power transmission / reception element V2 are electrically separated, so-called insulation. Since it is a type converter, when connecting the power transmission / reception element V1 and the power transmission / reception element V2 to the converter, it is necessary to devise a circuit so that the power transmission / reception element V1 and the power transmission / reception element V2 can be electrically connected. It should be understood that is gone. Further, in realizing an isolated converter, in the present invention, since a transformer or a bridge circuit of a switching means is not used, the number of circuit elements in the circuit is small, and the size of the circuit can be reduced.

The second and third embodiments of the bidirectional DC-DC converter according to the present invention In the converter shown in FIG. 1, the circuit (capacitor C1, switching means M1, M2) on the power transmission / reception element V1 side and the power transmission / reception element The circuit on the V2 side (capacitor C2, switching means M3, M4) is connected to the inductor (L1) via a pair of connecting capacitors (Cl1, Cl2), and the transfer of electric energy is performed on the transfer source side of the electric energy. After switching the switching means (M1 or M3) on the positive side to the ON state, the switching means on the positive side on the transfer destination side of the electric energy is switched to ON when dTs elapses, and the power transmission / reception element V1 side and the power transmission / reception element This is achieved by controlling the switching means on the V2 side. Therefore, in a circuit operation similar to this, in the converter, three or more circuits consisting of an input / output terminal pair connected to a power transmission / reception element, a capacitor, and two switching means connected in series are provided, and these are provided. The circuit can also be realized in a configuration in which the inductor is connected via a pair of connecting capacitors. Therefore, in the present invention, as illustrated in FIGS. 5 and 6, a circuit including three or more sets of input / output terminal pairs, a capacitor, and two switching means connected in series is connected to the inductor in a pair. A configuration connected via a capacitor is provided.

Thus, with reference to FIG. 5, in the second embodiment of the bidirectional DC-DC converter of the present invention, in addition to the configuration of the converter of FIG. 1, the anode and cathode of the power transmission / reception element V3 are further connected. Input / output terminal pairs ot + 3 (positive electrode side), ot-3 (negative electrode side), capacitors C3 connected by input / output terminal pair ot + 3, ot-3, and input / output terminal pair ot + 3, ot-3 Including a circuit consisting of two switching means M5 and M6 connected in series, the switching means M2 and M4 and the switching means M6 are connected via the connecting capacitor Cl3 and the inductor L2 on the positive electrode side thereof. It has a configuration in which it is connected via a connecting capacitor Cl4 on the negative electrode side thereof. Although not shown, the inductor L2 may be inserted in series with the connecting capacitor Cl4 at the connection line on the negative electrode side between the switching means M2 and M4 and the switching means M6, and may be inserted in series with the switching means M2 and M4. It may be inserted in series with the connecting capacitor Cl3 and the connecting capacitor Cl4 at both the positive electrode side and the negative electrode side connecting lines with the switching means M6. In such a configuration, the power transmission / reception element V3, the capacitor C3, the switching means M5, M6, the connecting capacitors Cl3, Cl4, and the inductor L2 may be the same as the corresponding circuit elements in the case of FIG. 1, respectively. ..

Even in the circuit configuration of FIG. 5, in the switching means M5 and M6, the states between the two terminals are predetermined in opposite phases as shown in FIGS. 2 (A) and 2 (B), respectively. It is controlled so as to be switched between the conduction state (ON state) and the cutoff state (OFF state) in the cycle Ts of. When the power transmission / reception element V3 serves as a transfer source of electric energy and supplies electric energy to the power transmission / reception element V1 or the power transmission / reception element V2 (V3> V1 or V2 is a condition), the switching means M5 The switching means M1 or M6 are controlled so that the switching means M1 or M3 is switched to the ON state when the time dTs elapses and the time of Phase II is longer than the time of Phase III after switching to the ON state. To. Then, the electric energy released by the power transmission / reception element V3 is charged to the power transmission / reception element V1 or the power transmission / reception element V2 in the same manner as those described in FIGS. On the other hand, when the power transmission / reception element V3 serves as a transfer destination of electric energy and receives electric energy from the power transmission / reception element V1 or the power transmission / reception element V2 (V3 <V1 or V2 is a condition), the switching means M5. Is switched to the ON state when the time dTs elapses after the switching means M1 or M3 is switched to the ON state, and the switching means M1 to M6 are controlled so that the time of Phase II becomes longer than the time of Phase III. To. Then, the electric energy released by the power transmission / reception element V1 or the power transmission / reception element V2 is charged to the power transmission / reception element V3 in the same manner as those described in FIGS. That is, it is possible to transfer electrical energy from any of the power transmission / reception elements V1 to V3 to any of the power transmission / reception elements V1 to V3 simply by changing the ON / OFF switching phase of the switching means M1 to M6. Become. Further, by adjusting the context of the switching timing between the conduction state and the cutoff state in the switching means M1 to M6 and the length relationship of each phase as described above, from any one power source or circuit element. It is also possible to transfer electrical energy to multiple other power sources or circuit elements at the same time. Thus, for example, as described in connection with FIG. 7, when the converter is used as a cell balancer for a row of cells connected in series, each cell is the nearest terminal of the three sets of input / output terminal pairs. It suffices if the circuit is configured so that it can be connected in pairs, and the circuit configuration is simplified.

Further, referring to FIG. 6, in the third embodiment of the bidirectional DC-DC converter of the present invention, in addition to the configuration of FIG. 5, the anode and the cathode of the power transmission / reception element V4 are further connected to each other. Output terminal pair ot + 4 (positive electrode side), ot-4 (negative electrode side), input / output terminal pair ot + 4, ot-4 connected capacitor C4, input / output terminal pair ot + 4, ot-4 A circuit including switching means M7 and M8 connected in series is included, and the switching means M8 of the circuit is a connecting capacitor on the positive electrode side of the switching means M6 of the circuit on the power transmission / reception element V3 side. It has a configuration in which Cl5 and the inductor L3 are connected via a connecting capacitor Cl6 on the negative electrode side thereof. That is, the converter of the third embodiment has a configuration in which two converters having the configuration shown in FIG. 1 are connected via an inductor and a pair of connecting capacitors. Although not shown, the inductor L3 may be inserted in series with the connecting capacitor Cl6 at the connection line on the negative electrode side between the switching means M6 and the switching means M8, and the switching means M6 and the switching means M8 It may be inserted in series with the connecting capacitor Cl5 and the connecting capacitor Cl6 at both the positive electrode side and the negative electrode side connecting wires. Even in such a configuration, the power transmission / reception element V4, the capacitor C4, the switching means M7, M8, the connecting capacitors Cl5, Cl6, and the inductor L3 are the same as the corresponding circuit elements in the case of FIG. 1, respectively. Good.

Also in the circuit configuration of FIG. 6, in the switching means M7 and M8, the states between the two terminals are predetermined in opposite phases as shown in FIGS. 2 (A) and 2 (B), respectively. It is controlled so as to be switched between the conduction state (ON state) and the cutoff state (OFF state) in the cycle Ts of. Then, when the power transmission / reception element V4 serves as a transfer source of electric energy, after the switching means M7 is switched to the ON state, the switching means M1, M3 or M5 is switched to the ON state when the time dTs elapses. The switching means M1 to M8 were controlled so that the time of phase II was longer than the time of phase III, and then the power transmission / reception element V4 was released in the same manner as that described in FIGS. The electric energy will be charged to the power transmission / reception element V1, V2 or V3. On the other hand, when the power transmission / reception element V4 serves as a transfer destination of electric energy, the switching means M1, M3, or M5 is switched to the ON state, and then the switching means M7 is switched to the ON state when the time dTs elapses. The switching means M1 to M8 are controlled so that the time of II is longer than the time of phase III, and the power transmission / reception elements V1, V2, or V3 are released in the same manner as those described in FIGS. The generated electric energy will be charged to the power transmission / reception element V4. That is, it is possible to transfer electrical energy from any of the power transmission / reception elements V1 to V4 to any of the power transmission / reception elements V1 to V4 simply by changing the ON / OFF switching phase of the switching means M1 to M8. Become. Further, by adjusting the context of the switching timing between the conduction state and the cutoff state in the switching means M1 to M8 and the length relationship of each phase as described above, from any one power source or circuit element. It is also possible to transfer electrical energy to multiple other power sources or circuit elements at the same time. Thus, for example, as described in connection with FIG. 7, when the converter is used as a cell balancer for a row of cells connected in series, each cell is the nearest terminal of the four sets of input / output terminal pairs. It suffices if the circuit is configured so that it can be connected in pairs, and the circuit configuration is simplified.

Although not shown, in the bidirectional DC-DC converter of the present invention, a pair of input / output terminals to which an anode and a cathode of a larger number of power transmission / reception elements are connected than in the cases of FIGS. A circuit consisting of a capacitor connected between the input / output terminal pair and two switching means connected in series between the input / output terminal pair is additionally provided via an inductor and a pair of connecting capacitors. May be connected. In that case as well, simply by changing the ON / OFF switching phase of the switching means, the power transmission / reception element connected to one of the input / output terminal pairs of the converter can be changed to the power transmission / reception element connected to another input / output terminal pair. It is possible to transfer electrical energy. Further, by adjusting the context of the switching timing between the conduction state and the cutoff state in each switching means and the length relationship of each phase as described above, a plurality of simultaneous power sources or circuit elements can be used. It is also possible to transfer electrical energy to other power sources or circuit elements. At that time, since the power transmission / reception elements are connected to each other via a connecting capacitor, their anodes or cathodes are not directly connected (they do not have equal potentials), and therefore, the transfer of electric energy is carried out. It should be understood that it is no longer necessary to devise circuits so that the power transmission and reception elements made can be electrically connected to each other, and such an isolated converter is achieved by connecting via a connecting capacitor. Therefore, it is possible to make the circuit of the converter compact, which is advantageous.

Although the above description has been made in connection with the embodiments of the present invention, many modifications and modifications can be easily made by those skilled in the art, and the present invention is limited to the embodiments exemplified above. It will be clear that it is not limited and is applied to various devices without departing from the concept of the present invention.

Claims (1)

A bidirectional DC-DC converter device
A first input / output terminal pair consisting of a positive electrode terminal and a negative electrode terminal connected to the anode and cathode of the first power supply or circuit element, respectively.
The first capacitor connected between the first input / output terminal pair and
The first and second switching means connected in series between the positive electrode terminal and the negative electrode terminal of the first input / output terminal pair are used, and both terminals are selectively electrically connected to each other. Switching means and
A second input / output terminal pair consisting of a positive electrode terminal and a negative electrode terminal connected to the anode and cathode of the second power supply or circuit element, respectively.
The second capacitor connected between the second input / output terminal pair and
A third and fourth switching means connected in series between the positive electrode terminal and the negative electrode terminal of the second input / output terminal pair are used, and both terminals are selectively electrically connected to each other. Including switching means
The second switching means and the positive electrode side terminal of the fourth switching means are connected via the first connecting capacitor, and the second switching means and the negative electrode side terminal of the fourth switching means are connected to each other. At least one first inductor is inserted in the connection line between the positive electrode side terminal and the negative electrode side terminal of the second switching means and the fourth switching means, which are connected via the second connecting capacitor. Being done
The states between both ends of the first switching means and the second switching means are switched between the conductive state and the cutoff state at predetermined cycles in opposite phases to each other.
The states between both ends of the third switching means and the fourth switching means are switched between the conductive state and the cutoff state in the predetermined cycle in opposite phases to each other.
When transferring electrical energy from the first power source or circuit element to the second power source or circuit element, the third switching means shuts off after the first switching means switches from the cutoff state to the conductive state. The time during which the first switching means and the third switching means are in the conductive state while switching from the state to the conductive state is such that the third switching means and the second switching means are in the conductive state. The state between both ends of the first to fourth switching means is controlled so as to be longer than the time of.
When transferring electrical energy from the second power source or circuit element to the first power source or circuit element, the first switching means shuts off after the third switching means switches from the cutoff state to the conductive state. The time during which the third switching means and the first switching means are in the conductive state while switching from the state to the conductive state is such that the first switching means and the fourth switching means are in the conductive state. A device in which the state between both ends of the first to fourth switching means is controlled so as to be longer than the time.

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