JPH11299003A - Insulating-type dc-dc converter, and electric system for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize size reduction, weight reduction, cost reduction and efficiency improvement for the automotive apparatus of an electric vehicle by a method, wherein a normal use and emergency use charger is composed of a single-current bidirectional insulating-type DC-DC power converter. SOLUTION: Switching circuits, which are composed of series circuits of semiconductor switches and saturable reactors and diodes connected in anti- parallel to the series circuits are connected between a main battery 4 and the primary winding 143P of an insulating transformer 143 and between a secondary winding 143S of the insulating transformer and an auxiliary battery 10 respectively. The ON/OFF of the switching circuits are controlled so as to supply a power from the main battery 4 to the auxiliary battery 10 side or from the auxiliary battery 10 to the main battery 4 side for charging the respective batteries.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated DC-DC power converter suitable for use in a charging system for an electric vehicle and an electric system for an electric vehicle provided with the power converter. .

[0002]

2. Description of the Related Art FIG. 10 shows a drive system of a typical series hybrid electric vehicle. In the figure, 1 is an engine, 2 is a generator, 3 is a converter,
Is a main power storage device for driving the vehicle, 5 is an inverter, 6 is a motor for driving the vehicle, 7 is a speed reducer, 8 is a differential gear, 9a and 9b.
Is a wheel. Reference numeral 10 denotes an auxiliary power storage device serving as a power supply for the auxiliary device 11, reference numeral 12 denotes a charger for charging the auxiliary power storage device 10 from the main power storage device 4, and reference numeral 13 denotes a charge for charging the main power storage device 4 from the auxiliary power storage device 10. It is a charger. Here, a DC-DC converter is usually used for the chargers 12 and 13. The voltage of the main power storage device 4 is about several hundred volts, whereas the auxiliary power storage device 10 corresponds to a battery of an engine vehicle, and has a voltage of 12V or 24V. For this reason, the chargers 12 and 13 are of an electrically insulating type.

In the system shown in FIG. 10, mechanical energy of the engine 1 is converted into electric energy by a generator (generator 2), and this electric energy is converted into mechanical energy again by a motor 6 via a converter 3 and an inverter 5. To drive the vehicle. This method is called a series type because the energy flows are in series. Further, in this system, the generator driven by the engine 1 outputs substantially constant power, and the difference between the generated power and the power required by the motor 6 is covered by charging and discharging from the main power storage device 4. ing.

[0004] In the system shown in FIG. 10, the generator 2 is operated by a motor by the generator 2 and the converter 3, and the engine 1 is started by the power of the main power storage device 4. Therefore, in this system, when the engine 1 is started, the electric power required for the start must remain in the main power storage device 4. Charger 13 is provided in case power of main power storage device 4 is insufficient for starting engine 1. That is, the charger 13 is operated, the DC power of the auxiliary power storage device 10 is converted, the main power storage device 4 is charged, and the engine 1 is started with this power. Then, after the engine 1 starts, the main power storage device 4 is charged by causing the generator 2 to operate as a generator.

FIG. 11 shows a typical drive system of a parallel hybrid electric vehicle. The same components as those in FIG. 10 are given the same numbers. FIG.
In 100, 100 is an engine, 102a and 102b are clutches, 103 is a generator, 101 is a converter,
04 is a transmission. The clutch 102a is connected to the engine 10
The clutch 102b is for the transmission 104 as in the case of the engine automobile. This system is called a torque assist system, and is a type of parallel system. In addition, the present system is a system in which the engine 100 can independently drive the vehicle, and the power generator 103 can also independently drive the vehicle.

When the engine is driven, the output of the engine 100 is input to the transmission 104 via the shaft of the generator 103 to drive the wheels 9a and 9b. The main power storage device 4 is charged. In the case of electric drive, the engine 100 is disconnected by the clutch 102a, and the generator 101 is driven by an electric motor by inverting the converter 101 with the power of the main power storage device 4. This operation method is the same as the series method. The engine 100 starts when the clutch 10
2b, disconnect the clutch 102a, and
03 is performed by operating the motor. This method is similar to the series method.

FIG. 12 shows a drive system for a battery-powered electric vehicle. The same components as those in FIGS. 10 and 11 are denoted by the same reference numerals. In FIG. 12, 4
0 is a main power storage device (main battery) for driving the vehicle, 50 is an inverter, 60 is a motor for driving the vehicle, and 70 is a speed reducer.
In an electric vehicle using a battery as a power source, if the power of the battery is insufficient, traveling cannot be continued. However, even in such a situation, it is necessary to be able to move the vehicle to a safe place. For this purpose, a charger 13 is mounted, the main power storage device 40 is charged by the power of the auxiliary power storage device 10, and the vehicle travels and moves with the power.

FIG. 13 shows a circuit configuration of charger 12 of auxiliary power storage device 10 shown in FIGS. Here, the charger 12 is a typical insulated two-stone DC
-It is constituted by a DC converter. In FIG. 13, reference numeral 120 denotes an input smoothing capacitor, 121P and 121N.
Is a semiconductor switch, and 122 is a semiconductor switch 1 on the primary side.
Insulation transformer connected in series between 21P and 121N, 1
22P is its primary winding, 122S is its secondary winding, 12P
3P, 123N are both ends of the capacitor 120 and the primary winding 1
A transformer exciting current return diode connected between both ends of the secondary winding 22P, 124 and 125 are output rectifier diodes connected to both ends of the secondary winding 122S, 126 is an output smoothing reactor, and 127 is an output smoothing capacitor.

The operation of the circuit shown in FIG. 13 will be described with reference to FIG. The semiconductor switches 121P and 121N are simultaneously turned on and off as shown in FIG. In the figure, T is one cycle of on and off, Ton indicates an on period, and Toff indicates an off period. By controlling the ratio of the ON period Ton to the cycle T, the charging current for the auxiliary power storage device 10 is controlled.

FIG. 15 shows a circuit configuration of charger 13 of main power storage device 4 or 40 shown in FIGS. Also in this case, the charger 13 is constituted by a typical insulated two-stone DC-DC converter. In FIG. 15, 130 is an input smoothing capacitor, 131P, 131
N is a semiconductor switch; 132 is an insulating transformer whose primary side is connected in series between the semiconductor switches 131P and 131N;
132P is its primary winding, 132S is its secondary winding, 1
33P and 133N are transformer excitation current return diodes connected between both ends of the capacitor 130 and both ends of the primary winding 132P, 134 and 135 are output rectifier diodes connected to both ends of the secondary winding 132S, and 136 is The output smoothing reactor 137 is an output smoothing capacitor.

When the circuit configuration of FIG. 15 is compared with that of FIG. 13, if the input / output side of FIG. 13 is reversed, the circuit of FIG. 15 is obtained. Since the two circuit configurations are symmetric and substantially the same, The description of the operation is omitted. Main power storage device 4 or 40 is charged by charger 13 shown in FIG.

[0012]

As shown in FIGS. 10 and 11, in a hybrid electric vehicle in which the engine is started by the power of the main power storage device 4, the engine can be started by using the power of the auxiliary power storage device 10. As described above, the auxiliary power storage device 1
The emergency charger 13 for charging the main power storage device from 0 is provided separately from the regular charger 12 for charging the auxiliary power storage device 10 from the main power storage device 4. In addition, as shown in FIG. 12, even in the case of an electric vehicle running only with the power of the main power storage device 40, the same emergency emergency as described above is prepared in case the power of the main power storage device 40 becomes exhausted and the vehicle becomes unable to run. Charger 13 for
It has.

[0013] As described above, the electric vehicle including the hybrid electric vehicle includes the emergency charger for the main power storage device in addition to the regular charger for the auxiliary power storage device. , Weight, high price, and the like have become problems, and their solutions are desired. Therefore, the present invention improves the charging system to reduce the size, weight, and price,
Insulated DC-DC power converters that have improved efficiency,
And an electric system for an electric vehicle having the conversion device.

[0014]

The conventional charger has no power controller in the output side circuit, and operates in a single quadrant in which the power is unidirectional. Therefore, the insulated DC-DC power converter of the present invention has been made with a focus on realizing a two-quadrant operation charger by providing a power control function on the output side of the conventional charger. is there.
That is, in the isolated DC-DC power converter of the present invention,
A series circuit of a semiconductor switch and a saturable reactor is connected in anti-parallel with the rectifier diode of the output circuit of the conventional charger, and a saturable reactor is connected in series to the semiconductor switch of the input circuit of the conventional charger. By connecting a diode to the series circuit in anti-parallel and having a rectification function, a two-quadrant operation type charger with current bidirectionality is realized. This makes it possible to realize a regular and emergency charger with a single insulated DC-DC power converter. By mounting this power conversion device on an electric vehicle, it is possible to reduce the size, weight, and cost of on-vehicle equipment.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a first embodiment of the present invention,
This corresponds to an embodiment of the invention described in claims 1, 4, and 5. The same components as those in FIG. 13 are denoted by the same reference numerals. In FIG. 1, reference numeral 14 denotes an insulated DC-DC power converter of the present invention, and reference numeral 14a denotes a first input terminal connected to a positive electrode of a main power storage device 4 as a first DC power supply;
4b is a second input terminal connected to the negative electrode of the main power storage device 4, and 14c is an auxiliary power storage device 10 as a second DC power supply.
The third input terminal 14d connected to the positive electrode of the power storage device 10 is a fourth input terminal connected to the negative electrode of the auxiliary power storage device 10.

Reference numeral 140 denotes a smoothing capacitor connected between the input terminals 14a and 14b. Reference numeral 143 denotes an insulating transformer having a primary winding 143P and a secondary winding 143S. Between the input terminals 14a and 14b and both ends of the primary winding 143P, a semiconductor switch 121P and a saturable reactor 142RP are connected. A series circuit, a series circuit of the semiconductor switch 121N and the saturable reactor 142RN is connected. Further, rectifier diodes 141P and 141N are connected in anti-parallel to these series circuits, respectively, and these anti-parallel circuits constitute first and second switch circuits.

As shown in FIG. 13, rectifier diodes 124 and 125 are provided at both ends of the secondary winding 143S of the insulating transformer 143.
Is connected. In this embodiment, a series circuit of the semiconductor switch 144P and the saturable reactor 145RP, the semiconductor switch 144N and the saturable reactor 14
A series circuit with 5RN is connected, and these antiparallel circuits form third and fourth switch circuits. 146 is a smoothing reactor on the auxiliary power storage device 10 side, and 147 is a smoothing capacitor. Here, the polarity of the windings 143P and 143S of the insulating transformer 143 is the same at each end with a dot.

In this embodiment, the semiconductor switches 121P, 121P constituting the first to fourth switch circuits
When N, 144P, and 144N are constituted by FETs as shown in FIG. 1, a parasitic diode exists in the FET element. The parasitic diode present in the semiconductor switch has the same polarity as the anti-parallel diode. That is, the parasitic diode is connected to the diode 141 connected in anti-parallel.
P, 141N, 124, and 125 are connected in parallel.

On the other hand, the diode 141 connected in anti-parallel
P, 141N, 124, and 125 are selected from their frequency characteristics in consideration of the switching frequency of the semiconductor switch circuit. The frequency characteristics of the parasitic diode in the FET are the diodes 141P, 141N,
Generally, the switching performance is worse than 124 and 125, and the switching performance of the switch circuit in which the parasitic diode is connected in parallel with the anti-parallel diode is limited by the frequency characteristics of the parasitic diode. That is, it is necessary to electrically disconnect the parasitic diode because it is accompanied by a restriction of a high frequency, an increase in switching loss, and an increase in electromagnetic noise. Saturable reactor 1 shown in FIG.
42RP, 142RN, 145RP, and 145RN are elements inserted for this function.

Next, the operation of the semiconductor switch circuit in FIG. 1 will be described with reference to FIG. FIG. 2A shows the semiconductor switch 121P and its peripheral circuits in FIG. 1 again. In FIG. 2A, 121Pd indicated by a broken line is a diode parasitic in the semiconductor switch 121P.

In FIG. 2B, the semiconductor switch 121P is turned on (not shown, but the semiconductor switch 121N is also turned on).
This is the operation of each unit when it is performed. When the semiconductor switch 121P (and 121N) is turned on at the time T1, FIG.
The voltage is applied to the saturable reactor 142RP in the direction of the dot in FIG. At the same time, a saturable reactor 1 (not shown)
42RN is similarly added. Saturable reactor 142R
The magnitude of the voltage applied to P (142RN) is の of voltage Vb of main power storage device 4, and is saturated at time T2. When the saturable reactor 142RP (142RN) is saturated, the load current I flows through the semiconductor switch 121P (121N) until the off time T3. Here, times T1 to T3 in FIG. 2B correspond to Ton shown in FIG.

FIG. 2C is a diagram showing the operation when a current flows in the direction of the thick arrow in FIG. 2A. Time T4
When a current flows through the diode 141P,
A voltage drop Vd occurs at both ends of 41P. This voltage V
d is the parasitic diode 121Pd and the saturable reactor 1
Joins the series circuit with the 42RP. Therefore, the voltage of the saturable reactor 142RP has a value obtained by subtracting the voltage drop of the parasitic diode 121Pd from the voltage Vd. The voltage drop of the parasitic diode 121Pd is
Since the voltage drop is substantially the same as the voltage drop Vd of 1P, the voltage of the saturable reactor 142RP becomes substantially zero. Therefore, the period Tof from time T4 to time T5 shown in FIG.
At f, the saturable reactor 142RP does not saturate and has a large impedance.
The current of 42RP, that is, the current of the semiconductor switch 121P becomes substantially zero, and the load current flows to the diode 141P.

Next, the operation of the circuit shown in FIG. 1 will be described. First, at the time of normal charging in which the auxiliary power storage device 10 is charged from the main power storage device 4, the semiconductor switches 144P and 144N are turned off, and the semiconductor switches 121P and 121N are turned on and off. In this case, the semiconductor switches 144P and 144N are off, and the saturable reactors 142RP and 142R
Since N, 145RP, and 145RN hardly affect the circuit operation, the circuit is substantially the same as that of FIG. 13, and the control and operation of the semiconductor switches 121P and 121N are also the same. Therefore, the operation of the entire circuit is the same as that of FIG.

Next, at the time of emergency charging for charging main power storage device 4 from auxiliary power storage device 10, semiconductor switch 121 is used.
P, 121N are turned off, and the semiconductor switches 144P, 14P are turned off.
4N is turned on / off. The circuit in this case has the circuit configuration of an insulated boost DC-DC converter. The circuit configuration at this time is shown in FIG. 3, the same components as those in FIG. 1 are given the same numbers. Semiconductor switch 1
Since 44P is used as a diode, it is indicated by a diode symbol in FIG. The semiconductor switch 144N is turned on and off to charge the low-voltage side auxiliary power storage device 10 to the high-voltage side main power storage device 4 via the insulating transformer 143.

FIG. 4 shows the operation in this case. In this operation, as shown in FIG. 4, the semiconductor switch 144P is turned off and the semiconductor switch 144N is turned on at the same time, and the semiconductor switch 144P is turned on and the semiconductor switch 144P is turned on at the same time.
Turn off 4N. In FIG. 4, T is one cycle of ON and OFF, and Ton is the ON period of the semiconductor switch 144N,
Toff indicates an off period of the semiconductor switch 144N. The charging current is controlled by controlling the ratio of the ON period Ton to the cycle T.

As described above, in the present embodiment, the conventional FIG.
3, both functions of the regular and emergency chargers 12 and 13 shown in FIG. 15 are combined with the insulated DC-DC power converter 1 shown in FIG.
4 can be realized by bidirectional two-quadrant operation of current. Comparing the number of semiconductor switches in that case, as described above, the number of both of FIGS. 13 and 15 remains the same, that is, four, and the number of insulating transformers is further reduced by half. When viewed as a charger, the device can be made smaller, lighter, less expensive, and more efficient.

FIG. 5 shows a second embodiment of the present invention, and corresponds to the second embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals. In FIG. 5, 142SP, 142SN, 145S
P and 145SN are circuit changeover switches. During normal charging, the circuit changeover switches 142SP, 142SN, 14
5SP and 145SN are all connected to the contact a side. As a result, the diodes 141P and 141N and the semiconductor switches 144P and 144N are disconnected from the circuit, and the circuit configuration is the same as that in FIG. The control is performed by the on / off control of the semiconductor switches 121P and 121N as in FIG. Further, since the semiconductor switches 144P and 144N are separated from the circuit, the above-mentioned problem due to these parasitic diodes does not occur.

In FIG. 5, at the time of emergency charging, the circuit changeover switches 142SP, 142SN, 145SP,
145SN are all connected to the contact b side. This allows
Semiconductor switches 121P, 121N, diode 12
4, 125 are disconnected from the circuit, and the circuit configuration is the same as that of the circuit for emergency charging in FIG. 1 (FIG. 3).
It becomes a C-DC converter. Therefore, the semiconductor switch 1
The main power storage device 4 is charged by turning on and off 44P and 144N. At this time, since the semiconductor switches 121P and 121N are disconnected from the circuit, the above-mentioned problem due to these parasitic diodes does not occur.

FIG. 6 shows a third embodiment of the present invention, which corresponds to another embodiment of the present invention. FIG. 6 shows only the secondary side of the insulating transformer 143, and the primary side is the same as FIG. In FIG.
A circuit switch 148 shares the circuit switches 145SP and 145SN of FIG. Here, the semiconductor switches 144P, 144 connected in series
N constitutes third and fourth switch circuits, respectively.

In FIG. 6, during normal charging, the semiconductor switches 144P and 144N are cut off from the circuit by connecting the circuit changeover switch 148 to the contact a side.
The circuit configuration is the same as that in normal charging in FIG. Also,
At the time of emergency charging, by connecting the circuit changeover switch 148 to the contact b side, the diodes 124 and 125 are disconnected from the circuit, and the circuit configuration becomes the same as that at the time of emergency charging in FIG. In this embodiment, since the semiconductor switches 144P and 144N are disconnected from the circuit during normal charging, the above-described problem due to these parasitic diodes does not occur.

FIG. 7 shows an embodiment of the invention described in claim 6, in which the insulated DC-DC power converter described in claims 1 to 5 is applied to a series hybrid electric vehicle. The same components as those in FIG. 10 are denoted by the same reference numerals, and the normal and emergency charger 1 in FIG.
In this configuration, DC power supplies 2 and 13 are replaced by the DC-DC power converter 14 shown in FIG.

FIG. 8 is also an embodiment of the invention described in claim 6, in which the insulated DC-DC power conversion device described in claims 1 to 5 is applied to a parallel hybrid electric vehicle. That is, the regular and emergency chargers 12 and 13 in FIG. 11 are replaced with the DC-DC power converter 14 in FIG.
The configuration is replaced by

FIG. 9 also shows an embodiment of the invention as set forth in claim 6, wherein the insulated DC-DC power converter according to claims 1 to 5 runs on only the power of the main power storage device 40. It is applied to That is, the regular and emergency chargers 12 and 13 in FIG.
This is a configuration in which the DC power conversion device 14 is replaced.

The operation of the DC-DC power converter 14 in the above-described embodiment of FIGS. 7 to 9 has been described with reference to FIGS.

In each of the above embodiments, the case where the power storage device is a chemical secondary battery has been described. However, other power storage devices such as a physical battery such as an electric double layer capacitor, a solar battery, a fuel cell, and the like. Of course, the present invention can be applied to a DC power supply having a voltage fluctuation. Although the description of the filter circuit other than the smoothing capacitor on the input side of the main power storage device is omitted, an appropriate filter circuit may be further connected as necessary. Furthermore, it goes without saying that the isolated DC-DC power converter according to the present invention can be applied not only to a charging system in an electric vehicle, but also to a current bidirectional DC-DC power conversion system between two power storage devices or a DC power supply. .

[0036]

As described above, according to the present invention, a two-way charging system between the first and second DC power sources, such as two power storage devices, is integrated to form an electrically insulated DC-DC power converter. Therefore, the following effects are obtained. (1) A compact, lightweight, and low-cost charger can be realized. (2) It can be applied to various charging systems including electric vehicles.

Further, when the insulated DC-DC power converter of the present invention is applied to an electric vehicle, the following effects are expected. (1) It is possible to reduce the size, weight, and cost of the charger. (2) Even if the power of the main power storage device is insufficient, the power of the auxiliary power storage device can start the engine or run in an emergency,
An electric vehicle with high running reliability can be realized. (3) The present invention can be applied to various power storage devices such as a chemical secondary battery having a large voltage fluctuation, an electric double layer capacitor, a solar cell, and a fuel cell, and a DC power supply. (4) It can greatly contribute to the spread and development of electric vehicles.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an insulated DC-DC power converter according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the switch circuit of FIG. 1;

FIG. 3 is a diagram showing a circuit configuration at the time of emergency charging in the embodiment of FIG. 1;

FIG. 4 is an operation explanatory diagram of FIG. 1;

FIG. 5 is a circuit configuration diagram of an insulated DC-DC power converter according to a second embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of an insulated DC-DC power converter according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a drive system for a series hybrid electric vehicle as a fourth embodiment of the present invention.

FIG. 8 is a diagram illustrating a drive system for a parallel hybrid electric vehicle according to a fifth embodiment of the present invention.

FIG. 9 is a diagram showing a drive system of a battery-driven electric vehicle as a sixth embodiment of the present invention.

FIG. 10 is a diagram showing a drive system of a series hybrid electric vehicle as a prior art.

FIG. 11 is a diagram showing a drive system of a parallel hybrid electric vehicle as a conventional technique.

FIG. 12 is a diagram showing a driving system of a battery-driven electric vehicle as a conventional technique.

FIG. 13 is a circuit configuration diagram of a charger of the auxiliary power storage device in FIGS.

FIG. 14 is an operation explanatory diagram of FIG. 13;

15 is a circuit configuration diagram of a charger of the main power storage device in FIGS. 10 to 12. FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1,100 Engine 2,103 Generator motor 3 Converter 4 Main power storage device 5 Inverter 6 Vehicle drive motor 7 Reduction gear 8 Differential gear 9a, 9b Wheel 10 Auxiliary power storage device 11 Auxiliary device 14 Insulated DC-DC power converter 14a, 14b , 14c, 14d Input terminals 102a, 102b Clutch 104 Reducer 121P, 121N, 144P, 144N Semiconductor switch 121Pd Parasitic diode 123P, 123N, 124, 125 Diode 140, 147 Smoothing capacitor 142RP, 142RN, 145RP, 145RN Saturable reactor 142SP, 142SN, 145SP, 145SN, 1
48 Circuit changeover switch 143 Insulation transformer 143P Primary winding 143S Secondary winding 146 Smoothing reactor

Claims (11)

[Claims] A first input terminal connected to first and second input terminals;
And a second power supply connected to the third and fourth input terminals.
An insulated DC-DC power converter that performs power conversion via an insulating transformer between the DC power supply and a first input terminal connected to a positive electrode of a first DC power supply;
A first switch circuit formed by connecting a diode in anti-parallel to a series circuit of a semiconductor switch and a saturable reactor is connected between one end of a primary winding of the insulating transformer and a first DC power supply. A second input terminal connected to the negative electrode,
A second switch circuit formed by connecting a diode in anti-parallel to a series circuit of a semiconductor switch and a saturable reactor between the other end of the primary winding and a semiconductor of the first and second switch circuits; The switch has a flowing direction from the first input terminal to the second input terminal, between the first input terminal and the other end of the primary winding, and between the second input terminal and the primary winding. A diode is connected between the first input terminal and the second input terminal with a polarity from the second input terminal to the first input terminal. The diode is connected to one end of a secondary winding of the insulating transformer and a positive electrode of a second DC power supply. A third switch circuit formed by connecting a diode in anti-parallel to a series circuit of a semiconductor switch and a saturable reactor, and a third input terminal; And the point of connection with the reactor Connecting a fourth switch circuit formed by connecting a diode in anti-parallel to a series circuit of a semiconductor switch and a saturable reactor between the other end of the secondary winding and the other end of the secondary winding. Is connected to a fourth input terminal connected to the negative electrode of the second DC power supply, and the semiconductor switch of the third switch circuit has a flow direction from the third input terminal to the secondary winding and , Fourth
Wherein the semiconductor switch of the switch circuit has a flowing direction from the third input terminal to the fourth input terminal, and one end of the primary winding and one end of the secondary winding of the insulating transformer have the same polarity. Insulated DC-DC power converter. 2. A first terminal connected to first and second input terminals.
And a second power supply connected to the third and fourth input terminals.
An insulated DC-DC power converter that performs power conversion via an insulating transformer between the DC power supply and a first input terminal connected to a positive electrode of a first DC power supply;
A first switch circuit is connected between one end of the primary winding of the insulating transformer and one of a semiconductor switch and a diode in a reverse direction via a first circuit changeover switch. A second input terminal connected to the negative electrode of the first DC power supply;
A second switch circuit is connected between the other end of the primary winding and one of a semiconductor switch and a diode in a reverse direction via a second circuit changeover switch, and The semiconductor switch of the second switch circuit has a flowing direction from the first input terminal to the second input terminal, between the first input terminal and the other end of the primary winding, and a second input terminal. A diode is connected between a terminal and one end of the primary winding with a polarity going from a second input terminal to a first input terminal, and one end of a secondary winding of the insulating transformer is connected to a second end. A third switch circuit configured to connect one of a semiconductor switch and a diode in the opposite direction via a third circuit switch between a third input terminal connected to a positive electrode of the DC power supply; With the reactor connected in series, the third Between the connection point between the switch circuit and the reactor and the other end of the secondary winding, one of a semiconductor switch and a diode in the opposite direction is connected via a fourth circuit changeover switch. A fourth switch circuit is connected, the other end of the secondary winding is connected to a fourth input terminal connected to a negative electrode of a second DC power supply, and a semiconductor switch of the third switch circuit is a third switch circuit. In the direction of flow from the input terminal to the secondary winding.
Wherein the semiconductor switch of the switch circuit has a flowing direction from the third input terminal to the fourth input terminal, and one end of the primary winding and one end of the secondary winding of the insulating transformer have the same polarity. Insulated DC-DC power converter. A first input terminal connected to the first and second input terminals;
And a second power supply connected to the third and fourth input terminals.
An insulated DC-DC power converter that performs power conversion via an insulating transformer between the DC power supply and a first input terminal connected to a positive electrode of a first DC power supply;
A first switch circuit is connected between one end of the primary winding of the insulating transformer and one of a semiconductor switch and a diode in a reverse direction via a first circuit changeover switch. A second input terminal connected to the negative electrode of the first DC power supply;
A second switch circuit is connected between the other end of the primary winding and one of a semiconductor switch and a diode in a reverse direction via a second circuit changeover switch, and The semiconductor switch of the second switch circuit has a flowing direction from the first input terminal to the second input terminal, between the first input terminal and the other end of the primary winding, and a second input terminal. A diode is connected between a terminal and one end of the primary winding with a polarity from the second input terminal to the first input terminal, and a diode is connected between one end and the other end of the secondary winding of the insulating transformer. A third and a fourth switch circuit in which two semiconductor switches are connected in series, and a diode circuit in which two diodes are connected in series, are respectively connected therebetween, and a connection point of the third and fourth switch circuits is connected to the diode. One of the circuit connection points
The other end of this reactor is connected to a third input terminal connected to the positive electrode of the second DC power supply, the other end of the secondary winding, The semiconductor switch of the third and fourth switch circuits is connected to a fourth input terminal connected to the negative electrode of the second DC power supply, and has a flow direction from the third input terminal to the secondary winding. In addition, the diode of the diode circuit has a flowing direction from the secondary winding toward the third input terminal, and one end of the primary winding of the insulating transformer and one end of the secondary winding have the same polarity. An isolated DC-DC power converter. 4. The insulated DC-DC power converter according to claim 1, 2 or 3, wherein the first and second switch circuits are controlled to control the third and third input terminals from the first and second input terminals. 4. An insulated DC-DC power converter, characterized by controlling the power supplied to the input terminal side of No. 4. 5. The insulated DC-DC power converter according to claim 1, 2 or 3, wherein the third and fourth switch circuits are controlled to control the first and fourth input terminals from the first and fourth input terminals. 2. An insulated DC-DC power converter, which controls the power supplied to the input terminal side of No. 2. 6. An electric vehicle comprising a main power storage device for driving a vehicle and an auxiliary power storage device for auxiliary equipment, wherein an electric power storage device is provided between the main power storage device and the auxiliary power storage device.
An electric system for an electric vehicle to which the insulated DC-DC power converter according to 3, 4, or 5 is connected. 7. The electric system for an electric vehicle according to claim 6, wherein the main power storage device is a chemical secondary battery. 8. The electric system for an electric vehicle according to claim 6, wherein the main power storage device is an electric double layer capacitor battery. 9. The electric system for an electric vehicle according to claim 6, wherein the main power storage device is a solar cell. 10. The electric system for an electric vehicle according to claim 6, wherein the main power storage device is a fuel cell. 11. The electric system for an electric vehicle according to claim 7, 8, 9 or 10, wherein the auxiliary power storage device is an electric double layer capacitor battery.