JP4546296B2 - DC / DC converter device - Google Patents

Description

This invention converts a DC voltage to boost or buck DC voltage, to a D C / DC converter apparatus.

  A conventional switched capacitor type DC / DC converter device includes m (m is an integer of 2 or more) switched capacitor transformers connected in parallel, and each transformer includes a capacitor and a plurality of switching transistors. Is done. Each switched capacitor transformer switches a switching transistor that alternately switches between charging and discharging the capacitor to a clock signal that is shifted in phase by 2π / m (rad) according to a predetermined input voltage, or a normally on or a normally off state. (See, for example, Patent Document 1).

Japanese Utility Model Publication No. 1-147785

  In such a conventional switched capacitor type DC / DC converter device, the power is transferred by alternately switching the charge and discharge of the capacitor. However, if the amount of power to be transferred is increased, the capacity of the capacitor is increased or the switch element is switched. This increases the switching frequency. The increase in the capacitor capacity has a problem that the converter device becomes large. In addition, an increase in switching frequency requires a high-speed and high-precision control circuit element corresponding to a high frequency, and a gate drive circuit with high driving power is required to drive the switch element at high speed. There is a problem of high cost of the apparatus.

This invention, which was made in order to solve the above problems, for the purpose of obtaining D C / DC converter apparatus that can increase the amount of power to shift by a simple circuit structure compact Yes.

A DC / DC converter device according to the present invention includes a capacitor and a plurality of semiconductor switching elements between a low-voltage side DC power source and a high-voltage side DC power source, and charging / discharging of the capacitor by a switching operation of the semiconductor switching element. Are switched alternately to transfer energy between the two power sources. Then, by inserting the inductor path section and discharging path and a charging path of the capacitor overlap with said capacitor and said inductor are connected in series to the charging and discharging of the capacitor, to drive the plurality of semiconductor switching element driving The period of the signal is changed according to the amount of current flowing through the inductor so as to substantially match the resonance period of the capacitor and the inductor .

In such a DC / DC converter apparatus, we use the resonance phenomenon of the capacitor and inductor placed an inductor charge path and discharge path of the capacitor. Thus, the amount of energy that can be transferred by one switching operation can be increased, and the amount of power to be transferred can be increased without increasing the capacitance of the capacitor or increasing the switching frequency of the semiconductor switching element.

Embodiment 1 FIG.
Hereinafter, D C / DC converter apparatus that by the first embodiment of the present invention (hereinafter, referred to as the converter device) to the drawings will be described.
1 is a diagram showing a main circuit configuration of a converter apparatus according to Embodiment 1 of the present invention.
As shown, one SC type (switched capacitor type) converter block 1 is connected between a low voltage side (VL side) DC power source and a high voltage side (VH side) DC power source. Smoothing capacitors CL and CH for smoothing the voltage are connected between both terminals 2 and 2a of the low voltage side DC power source and between both terminals 3 and 3a of the high voltage side DC power source. The negative terminal 2a and the negative terminal 3a of the high voltage side DC power supply are grounded.

The converter block 1 includes MOSFETs (hereinafter referred to as switches) Sw1 to Sw4 as four semiconductor switching elements, a capacitor Ce, and an inductor Lr.
The drain terminal of the switch Sw1 as the first semiconductor switching element is connected to the positive terminal 3 of the high voltage side DC power supply. The switch Sw2 as the second semiconductor switching element has a drain terminal connected to the source terminal of the switch Sw1 and a source terminal connected to the positive terminal 2 of the low-voltage DC power supply. The source terminal of the switch Sw3 as the third semiconductor switching element is connected to the negative terminal 3a of the high voltage side DC power source and the negative terminal 2a of the low voltage side DC power source. The switch Sw4 as the fourth semiconductor switching element has a source terminal connected to the drain terminal of the switch Sw3 and a drain terminal connected to the positive terminal 2 of the low-voltage side DC power supply. The capacitor Ce and the inductor Lr are connected in series, and are connected between the connection point of the switches Sw1 and Sw2 and the connection point of the switches Sw3 and Sw4.

A gate drive signal (hereinafter referred to as a gate signal) generated by a control circuit unit (not shown) is input to each of the switches Sw1 to Sw4, and an on / off operation is performed according to the voltage level of the gate signal. Note that the voltage between the terminals 2 and 2a of the low voltage side DC power supply is VL, and the voltage between the terminals 3 and 3a of the high voltage side DC power supply is VH.
By switching between simultaneous conduction of switches Sw2 and Sw3 and simultaneous conduction of switches Sw1 and Sw4, when 2VL> VH, power is transferred from the low voltage side to the high voltage side, and when 2VL <VH The power is transferred from the high voltage side to the low voltage side. The basic operation of the converter device in each case will be described below. As will be described later, the series resonance phenomenon of the inductor Lr and the capacitor Ce is used, but here, for the sake of convenience, the operation of the inductor Lr will be ignored in order to explain the basic operation of power transfer.

  When 2VL> VH, when the switches Sw2 and Sw3 are on, the switches Sw1 and Sw4 are off, and the currents are smoothing capacitor CL (low voltage side positive terminal 2) to switch Sw2 to inductor Lr to capacitor Ce to switch Sw3 to It flows through the path of the ground terminal 2a. As a result, the smoothing capacitor CL and the capacitor Ce on the low voltage side are connected in parallel, and the capacitor Ce is charged to VL by the inter-terminal voltage VL on the low voltage side. Next, when the switches Sw2 and Sw3 are turned off and the switches Sw1 and Sw4 are turned on, the current is changed from the smoothing capacitor CL (low voltage side positive terminal 2) to the switch Sw4 to the capacitor Ce to the inductor Lr to the switch Sw1 to the smoothing capacitor CH. Flows through the path of the ground terminals 3a and 2a. Thereby, the smoothing capacitor CL and the capacitor Ce are connected in series, and the series body is connected in parallel with the smoothing capacitor CH. Since the smoothing capacitor CL and the capacitor Ce are at the voltage VL, the voltage of the series body is 2VL. Since the terminal voltage VH on the high voltage side is smaller than 2VL, the energy shifts from the low voltage side to the high voltage side.

  In the case of 2VL <VH, when the switches Sw1 and Sw4 are on, the switches Sw2 and Sw3 are off, and the current is the smoothing capacitor CH (high voltage side positive terminal 3) to the switch Sw1 to the inductor Lr to the capacitor Ce to the switch Sw4 to It flows through the path from the smoothing capacitor CL to the ground terminals 2a and 3a. Thereby, the smoothing capacitor CL and the capacitor Ce are connected in series, and the series body is connected in parallel with the smoothing capacitor CH. Since the voltages of the smoothing capacitors CL and CH are VL and VH, the capacitor Ce is charged with the voltage VH−VL. Next, when the switches Sw1 and Sw4 are turned off and the switches Sw2 and Sw3 are turned on, the current flows through a path from the capacitor Ce to the inductor Lr to the switch Sw2 to the smoothing capacitor CL to the switch Sw3. As a result, the smoothing capacitor CL and the capacitor Ce on the low voltage side are connected in parallel. Since the voltages of the smoothing capacitor CL and the capacitor Ce are VL and VH−VL, and VL <VH−VL, the energy is high so that the voltage of the capacitor Ce is equal to the voltage VL between the terminals on the low voltage side. Transition from the voltage side to the low voltage side.

Thus, in this converter device, VH / VL operates so as to transfer power bidirectionally in a relation of approximately two.
In either direction, the simultaneous conduction of the switches Sw2 and Sw3 and the simultaneous conduction of the switches Sw1 and Sw4 are alternately switched, and the gate signals of the switches Sw2 and Sw3 and the gate signals of the switches Sw1 and Sw4 have the same shape. By switching the switching operation, the capacitor Ce is switched between charging and discharging to perform power transfer.However, since the inductor Lr is inserted in a section where the current path during charging and the current path during discharging overlap, Both current paths during discharge are paths in which the inductor Lr, the capacitor Ce, and the resistance of the path through which the current flows are connected in series. For this reason, the switching frequency of the gate signals of the switches Sw2 and Sw3 and the gate signals of the switches Sw1 and Sw4 is made to coincide with the resonance frequency at which the inductor Lr and the capacitor Ce are in a series resonance state.

  The capacitance value of the capacitor Ce is Ce, the inductance value of the inductor Lr is Lr, the resistance of the path through which the current flows, that is, the sum of the on-resistance of the switch Sw2, Sw3 or the switch Sw1, Sw4 and the resistance component of the capacitor Ce, the inductor Lr. Assuming R, the period T of the gate signal can be expressed by the following equation (1).

As described above, when the inductor Lr and the capacitor Ce are in a series resonance state, the gate signals of the switches Sw1 to Sw4 and the voltage and current waveforms of the respective parts are shown in FIG. FIG. 2A shows the case of 2VL> VH, and FIG. 2B shows the case of 2VL <VH. The current flowing from the positive terminal 2 of the low voltage side DC power supply to the converter block 1 is IL, the current flowing from the converter block 1 to the positive terminal 3 of the high voltage side DC power supply is IH, the current flowing to the capacitor Ce is Ice, and the capacitor Ce. Is Vce. Also, the direction of the current and voltage arrows shown in FIG. 2 is positive.
As shown in the figure, the switches Sw2, Sw3 and the switches Sw1, Sw4 are turned on and off at the timing when the current Ice flowing through the capacitor Ce becomes zero, and the current Ice flowing through the capacitor Ce is continuous as shown in FIG. It becomes a sinusoidal current. Further, the current IL has a current waveform in which the current Ice is converted into an absolute value in either a positive or negative direction, and the current IH has a current waveform obtained by taking out only the ON periods of the switches SW1 and Sw4 of the current IL.

Further, the voltage Vce of the capacitor Ce is a voltage that oscillates in a sine wave shape centered on the voltage VL, and the voltage shows the maximum value and the minimum value at the switching timing of each gate signal.
As shown by the waveform of the voltage Vce, the voltage Vce of the capacitor Ce changes from VL + ΔV to VL−ΔV at the time of energy transfer. If the resonance phenomenon is not used, energy is transferred only by the amount of charge of (2VL−VH), whereas in this embodiment, energy can be transferred with a larger amount of charge than (2VL−VH).

  In this way, in this embodiment, since the series resonance phenomenon of the inductor Lr and the capacitor Ce is used, the current Ice flowing through the capacitor Ce can be made a continuous sinusoidal current, and the capacitor Ce used per switching The amount of stored energy can be increased. Therefore, it is possible to increase the amount of power transferred with a small and simple circuit configuration without increasing the capacitor capacity and increasing the switching frequency.

Next, using a converter device having the circuit configuration shown in FIG. 1 and having no inductor Lr as a comparative example, a characteristic comparison is made between the example (with inductor Lr) and the comparative example (without inductor Lr) in this embodiment. The results are shown in FIG.
FIG. 3A shows the relationship between the capacitance value Ce of the capacitor Ce and the amount of power transferred per switching from the low voltage side to the high voltage side. The calculation conditions are as shown in FIG. As shown in b), VL / VH = 144V / 284V, capacitor Ce charging and discharging path resistance value R was 40 mΩ, inductor Lr inductance value Lr was 1 μH, and the maximum drive frequency was 100 kHz.
In addition, the driving frequency (the frequency of the gate signal) of the embodiment using the series resonance phenomenon of the inductor Lr and the capacitor Ce (with the inductor Lr) is premised on switching at a timing when the current Ice flowing through the capacitor Ce becomes zero. , Based on the formula (1), whichever is smaller.

  The drive frequency of the comparative example (without the inductor Lr) is obtained based on the time constant, and is the smaller one of the following.

  As shown in FIG. 3, the embodiment according to the present invention (with inductor Lr) shifts a large amount of power with a small capacitor capacity as compared with the comparative example (without inductor Lr).

  In the above embodiment, the inductor Lr is connected in series with the capacitor Ce and connected between the connection point of the switches Sw1 and Sw2 and the connection point of the switches Sw3 and Sw4, but the connection point of the switches Sw1 and Sw2 Further, only the capacitor Ce may be connected between the connection points of the switches Sw3 and Sw4, and the inductor Lr may be inserted between the low voltage side positive terminal 2 and the connection points of the switches Sw1 and Sw2. Also in this case, since the inductor Lr is inserted in the section where the current path during charging and the current path during discharging overlap, the series resonance phenomenon of the inductor Lr and the capacitor Ce can be used as in the above embodiment. A similar effect can be obtained.

Embodiment 2. FIG.
In the first embodiment, when an inductor Lr manufactured using a small magnetic body for miniaturization and allowing a certain amount of magnetic saturation of the magnetic body is used, the inductor Lr depends on the flowing current level (transition power level). The inductance value changes. FIG. 4A shows the relationship between the amount of transition power depending on the amount of current flowing through the inductor Lr and the inductance value / current value of the inductor Lr. As shown in the figure, the inductance value decreases as the amount of electric power (current amount) increases.
For this reason, in this embodiment, the drive frequency is made variable, and the drive frequency is set to substantially coincide with the resonance frequency that changes in accordance with the change in the inductance value. Here, as shown in FIG. 4B, the transition power region is divided into four, and the drive frequency is changed for each region. 11 is a resonance frequency that varies depending on the amount of power transferred, and 12 is a drive frequency (set frequency) that is switched according to the resonance frequency 11. For example, a storage unit (not shown) is provided, and four types of clock signals having different frequencies are stored in the storage unit in advance, a DC current value on the low voltage side is detected, and a clock is generated from the storage unit according to the current value. The signal is called, and the gate signal of each switch Sw1 to Sw4 is generated by using the signal.

  As described above, in this embodiment, the drive frequency is variable, and the drive frequency is set so as to substantially match the resonance frequency even when the resonance frequency changes. Therefore, a small magnetic body is allowed to allow some magnetic saturation. The inductor Lr can be used, and the circuit configuration can be made inexpensive and small.

Embodiment 3 FIG.
In the first embodiment, the SC converter block 1 connected between the low voltage side (VL side) DC power source and the high voltage side (VH side) DC power source is composed of four switches Sw1 to Sw4 and a capacitor Ce. In the third embodiment, the converter block 1 is composed of diodes Di1 and Di2 as first and second diodes, and a switch (MOSFET) Sw3a as first and second semiconductor switching elements. , Sw4a, capacitor Ce and inductor Lr.
FIG. 5 is a diagram showing a main circuit configuration of a converter device according to Embodiment 3 of the present invention.
As shown in the figure, similar switches Sw3a and Sw4a are used instead of the switches Sw3 and Sw4 shown in the first embodiment. Also, instead of the switches Sw1 and Sw2 shown in the first embodiment, the diode Di1 whose cathode terminal is connected to the positive terminal 3 on the high voltage side, the cathode terminal is connected to the anode terminal of the diode Di1, and the anode terminal is the switch A diode Di2 connected to Sw4a is used. Further, only the capacitor Ce is connected between the connection point of the diodes Di1 and Di2 and the connection point of the switches Sw3a and Sw4a, and the connection point of the diode Di2 and the switch Sw4a is connected to the positive terminal 2 on the low voltage side via the inductor Lr. Connecting.
Note that the position of the inductor Lr only needs to be connected in series with the capacitor Ce when the capacitor Ce is charged and discharged, and therefore may be the same position as that of the first embodiment (FIG. 1).

Next, the operation will be described.
By switching the switching frequency of the gate signal of the switch Sw3a and the gate signal of the switch Sw4a to the resonance frequency at which the inductor Lr and the capacitor Ce are in a series resonance state, and alternately switching the switch Sw3a and the switch Sw4a, 2VL> VH At this time, power is transferred from the low voltage side to the high voltage side. Here, only energy transfer from the low voltage side to the high voltage side is performed, and the same current and voltage waveforms shown in FIG. 2A of the first embodiment are obtained.
The diode Di1 is turned on by the electromotive voltage of the inductor Lr and the voltage of the capacitor Ce while the switch Sw4a is turned on and the current flows toward the high-voltage side positive terminal 3. While the switch Sw3a is turned on and a current flows from the low voltage side positive terminal 2, the diode Di2 is turned on by an electromotive voltage of the inductor Lr and a voltage difference between the low voltage side positive terminal 2 and the capacitor Ce voltage. Both diodes Di1 and Di2 are automatically turned off when the current direction is reversed.

  Also in this embodiment, since the series resonance phenomenon of the inductor Lr and the capacitor Ce is used, the current Ice flowing through the capacitor Ce can be changed to a continuous sinusoidal current, and the amount of energy stored in the capacitor Ce used per switching. Can be increased. For this reason, it is possible to increase the amount of power transferred with a small and simple circuit configuration without increasing the capacitor capacity or increasing the switching frequency. Further, since the plurality of semiconductor switching elements are two switches Sw3a and Sw4a, the gate drive circuit can be simplified.

Embodiment 4 FIG.
In the first embodiment, the SC converter block 1 connected between the low voltage side (VL side) DC power source and the high voltage side (VH side) DC power source is composed of four switches Sw1 to Sw4 and a capacitor Ce. In the fourth embodiment, the converter block 1 is composed of switches (MOSFETs) Sw1a and Sw2a as first and second semiconductor switching elements, and a diode Di3 as first and second diodes. , Di4, capacitor Ce and inductor Lr.
FIG. 6 is a diagram showing a main circuit configuration of a converter device according to Embodiment 4 of the present invention.
As shown in the figure, similar switches Sw1a and Sw2a are used instead of the switches Sw1 and Sw2 shown in the first embodiment. Further, instead of the switches Sw3 and Sw4 shown in the first embodiment, the diode Di3 whose anode terminal is connected to the ground terminals 2a and 3a, the anode terminal is connected to the cathode terminal of the diode Di3, and the cathode terminal is the switch Sw2a. And a diode Di4 connected to. Further, only the capacitor Ce is connected between the connection point of the diodes Di3 and Di4 and the connection point of the switches Sw1a and Sw2a. Connecting.
In this case as well, the position of the inductor Lr only needs to be connected in series with the capacitor Ce when the capacitor Ce is charged / discharged, and therefore may be the same position as in the first embodiment (FIG. 1).

Next, the operation will be described.
By switching the switching frequency of the gate signal of the switch Sw1a and the gate signal of the switch Sw2a to the resonance frequency at which the inductor Lr and the capacitor Ce are in a series resonance state, and switching the switch Sw1a and the switch Sw2a alternately, 2VL <VH At this time, power is transferred from the high voltage side to the low voltage side. Here, only energy transfer from the high voltage side to the low voltage side is performed, and the same current and voltage waveforms shown in FIG. 2B of the first embodiment are obtained.
The diode Di3 is turned on by the electromotive voltage of the inductor Lr and the voltage of the capacitor Ce while the switch Sw2a is turned on and current flows from the capacitor Ce to the low-voltage side positive terminal 2. While the switch Sw1a is turned on and a current flows from the high-voltage side positive terminal 3 to the low-voltage side, the diode Di4 generates the voltage generated by the inductor Lr and the capacitor Ce voltage superimposed on the low-voltage side positive terminal 2 and the high voltage. The differential voltage with respect to the side terminal 3 is turned on. Both diodes are automatically turned off when the current direction is reversed.

  Also in this embodiment, since the series resonance phenomenon of the inductor Lr and the capacitor Ce is used, the current Ice flowing through the capacitor Ce can be changed to a continuous sinusoidal current, and the amount of energy stored in the capacitor Ce used per switching. Can be increased. For this reason, it is possible to increase the amount of power transferred with a small and simple circuit configuration without increasing the capacitor capacity or increasing the switching frequency. Further, since the plurality of semiconductor switching elements are two switches Sw1a and Sw2a, the gate drive circuit can be simplified.

Embodiment 5 FIG.
In the first to fourth embodiments, one SC converter block 1 is connected between the low voltage side (VL side) DC power source and the high voltage side (VH side) DC power source. In this embodiment, A plurality of such SC converter blocks are connected in parallel.
FIG. 7 is a diagram showing a main circuit configuration of a converter device according to Embodiment 4 of the present invention.
As shown in the figure, four SC cells 1a to 1d comprising SC converter blocks similar to the converter block 1 shown in the first embodiment are connected to a low voltage side (VL side) DC power source and a high voltage side ( VH side) Connect in parallel with the DC power supply. Similarly to the first embodiment, smoothing capacitors CL and CH for smoothing the voltage are connected between the low voltage side terminals 2 and 2a and between the high voltage side terminals 3 and 3a. The voltage side negative terminal 2a and the high voltage side negative terminal 3a are grounded.

The reference clock signal for driving each of the SC cells 1a to 1d is shifted by 2π / 4 (rad). In this way, by shifting the reference clock signal by 2π / 4 (rad), the gate signals of the switches Sw1 to Sw4 constituting the 1a to 1d are also shifted by 2π / 4 between the SC cells 1a to 1d. Further, the frequency of the clock signal is made to coincide with the resonance frequency at which the inductor Lr and the capacitor Ce are in a series resonance state, and the switching frequency of the switch in each of the SC cells 1a to 1d is made to coincide with the resonance frequency. The operations in the cells 1a to 1d are the same as those in the first embodiment.
As a result, four times the amount of power can be transferred in the four SC cells 1a to 1d, and the ripple current of the smoothing capacitors CL and CH can be reduced. Since the capacitance values (size) of the smoothing capacitors CL and CH are determined depending on the magnitude of the ripple current value, the capacitance (size) of the smoothing capacitors CL and CH can be reduced by reducing the ripple current.

In this embodiment, four SC cells 1a to 1d are used. However, other plural (n) cells may be used, and the reference clock signal is similarly shifted by 2π / n (rad). Operate. In this case, the larger the number of SC cells, the greater the effect of reducing the ripple current of the smoothing capacitors CL and CH, and the size of the smoothing capacitors CL and CH can be reduced.
Moreover, although the said Embodiment 1 was applied to each SC cell 1a-1d, you may apply the said Embodiments 2-4.

Embodiment 6 FIG.
In the above-described first to fifth embodiments, the converter device in which VH / VL shifts power in the relationship of approximately 2 between the low voltage side (VL side) DC power source and the high voltage side (VH side) DC power source is shown. However, in this embodiment, a case where the voltage ratio is 4 where VH is about 4VL will be described.
FIG. 8 shows a main circuit configuration of the converter apparatus according to the sixth embodiment of the present invention.
As shown in the figure, an SC converter device 10 is connected between a low voltage side (VL side) DC power source and a high voltage side (VH side) DC power source. Smoothing capacitors CL and CH for smoothing the voltage are connected between the low voltage side terminals 2 and 2a and between the high voltage side terminals 3 and 3a. The low voltage side negative terminal 2a and the high voltage side negative terminal 3a is grounded.
As shown in the figure, the converter device 10 includes four switches Sw100, Sw203, Sw303, Sw404, a capacitor Ce3, and an inductor Lr3 in the same configuration as the converter block 1 of the first embodiment. Among these element configurations, the three switches Sw202, Sw302, Sw402, the capacitor Ce2 and the unit similar to the unit composed of the three switches Sw203, Sw303, Sw404, the capacitor Ce3, and the inductor Lr3 An inductor Lr2 and three switches Sw201, Sw301, Sw401, a capacitor Ce1, and an inductor Lr1 are provided.

  In FIG. 8, the source terminal of the switch Sw201 is connected to the positive terminal 2 on the low voltage side, the source terminal of the switch Sw202 is connected to the drain terminal of the switch Sw201, and the source terminal of the switch Sw203 is connected to the drain terminal of the switch Sw202. However, like the converter device 10a shown in FIG. 9, the source terminals of the switches Sw201 to Sw203 may be connected to the low-voltage side positive terminal 2, and the same operation described later can be obtained.

Each of the switches Sw100, Sw201 to 203, Sw301 to 303, and Sw401 to 403 receives a gate signal generated by a control circuit unit (not shown), and performs an on / off operation according to the voltage level of the gate signal.
FIG. 10 shows the gate signal of each switch and the voltage and current waveforms of each part. Note that VL, VH, IL, and IH are voltages and currents for the same parts as in the first embodiment, and currents that flow through the capacitors Ce1 to Ce3 and voltages of the capacitors Ce1 to Ce3 are also shown. Further, the directions of the current and voltage arrows shown in FIG. 8 are positive.
By alternately switching the simultaneous conduction of the switches Sw201 to 203 and Sw301 to 303 and the simultaneous conduction of the switches Sw100 and Sw401 to 403, when 4VL> VH, the power is transferred from the low voltage side to the high voltage side. In the case of <VH, power is transferred from the high voltage side to the low voltage side. The operation of the converter device in each case will be described below with reference to FIGS. 10 (a) and 10 (b).

As shown in FIG. 10A, when 4VL> VH, when the switches Sw201 to 203 and Sw301 to 303 are on, the switches Sw100 and Sw401 to 403 are off. At this time, the capacitors Ce1 to Ce3 and the inductors Three series bodies (Ce1, Lr1), (Ce2, Lr2), and (Ce3, Lr3) in which Lr1 to Lr3 are connected in series are simultaneously connected in parallel between both terminals 2 and 2a of the low voltage side DC power supply. As a result, the voltages of the capacitors Ce1 to Ce3 are charged to VL + ΔV.
Next, when the switches Sw201 to 203 and Sw301 to 303 are turned off and the switches Sw100 and Sw401 to 403 are turned on, the three series-connected bodies (Ce1, Lr1), (Ce2, Lr2), (Ce3, Lr3) and the smoothing capacitor CL are connected in series, and these series-connected composite series CL- (Ce1, Lr1)-(Ce2, Lr2)-(Ce3, Lr3) are both terminals 3 of the high-voltage side DC power supply, 3a are connected in parallel. The energy shifts from the low voltage side to the high voltage side, the capacitors Ce1 to Ce3 are discharged, and the voltage becomes VL−ΔV.

As shown in FIG. 10B, when 4VL <VH, when the switches Sw201 to 203 and Sw301 to 303 are on, the switches Sw100 and Sw401 to 403 are off, and at this time, the three series bodies (Ce1, Lr1), (Ce2, Lr2), and (Ce3, Lr3) are simultaneously connected in parallel between both terminals 2 and 2a of the low voltage side DC power supply. The energy shifts from the high voltage side to the low voltage side, the capacitors Ce1 to Ce3 are discharged, and the voltage becomes VL−ΔV.
Next, when the switches Sw201 to 203 and Sw301 to 303 are turned off and the switches Sw100 and Sw401 to 403 are turned on, the three series bodies (Ce1, Lr1), (Ce2, Lr2), and (Ce3, Lr3) are smoothed. The capacitor CL is connected in series, and these series-connected composite series bodies CL- (Ce1, Lr1)-(Ce2, Lr2)-(Ce3, Lr3) are parallel between the terminals 3 and 3a of the high-voltage side DC power supply. Connected. As a result, the voltages of the capacitors Ce1 to Ce3 are charged to VL + ΔV.

  As described above, a plurality of (in this case, three) series bodies (Ce, Lr) in which a pair of capacitors Ce (Ce1 to Ce3) and inductors Lr (Lr1 to Lr3) are connected in series are provided. A first mode in which a series body (Ce, Lr) is simultaneously connected in parallel between both terminals 2 and 2a of the low voltage side DC power supply, and a plurality of series bodies (Ce, Lr) are connected to the low voltage side DC power supply (smoothing capacitor). CL) are simultaneously connected in series, and a plurality of capacitors Ce1 to Ce3 are alternately switched to the second mode in which the series connected composite series body is connected in parallel between both terminals 3 and 3a of the high voltage side DC power source. Switching between charging and discharging at the same time. The resistance component of the charge / discharge path is almost negligible. In the first mode, the resonance period Ta in which each inductor Lr and each capacitor Ce is in a series resonance state has the inductance value of each Lr as Lr, When the capacitance value of Ce is Ce, it can be expressed by the following formula (2).

  Further, in the second mode, the resonance period Tb in which each inductor Lr and each capacitor Ce is in a series resonance state is represented by the following equation (where Lr is the inductance value of each Lr and Ce is the capacitance value of Ce): It can be expressed by 3).

From the above equations (2) and (3), Ta = Tb, and the two types of gate signals used in the first and second modes are a rectangular pulse signal with a simple duty ratio of 50%, as in the first embodiment. Become.
In this way, even when voltage conversion is performed at a voltage ratio of 4, the stored energy amount of the capacitor Ce used per switching can be increased by utilizing the series resonance phenomenon of the inductor Lr and the capacitor Ce. For this reason, it is possible to increase the amount of power transferred with a small and simple circuit configuration without increasing the capacitor capacity or increasing the switching frequency.

Even if the circuit configuration shown in FIG. 1 of the first embodiment is provided in two stages, a converter device having a similar voltage ratio of 4 can be configured. In this case, it is necessary to provide a smoothing capacitor between the first stage and the second stage. However, in the configuration shown in FIGS. 8 and 9, both the low voltage side terminals 2 and 2a and the high voltage side terminals 3 are provided. Only the smoothing capacitors CL and CH connected between 3a are sufficient.
In addition, although the DC voltage conversion mode with a voltage ratio of 4 has been described, the voltage ratio may be an integer of 2 or more, and the above unit including a series body in which a capacitor Ce and an inductor Lr are connected in series and a plurality of switches is included. By further increasing the power, it is possible to transfer power at a larger voltage ratio.

  In the first to sixth embodiments, MOSFETs are used as the semiconductor switching elements. However, similar effects can be obtained by using other semiconductor switching elements such as IGBTs.

It is a figure which shows the main circuit structure of the converter apparatus by Embodiment 1 of this invention. It is a figure explaining operation | movement of the converter apparatus by Embodiment 1 of this invention. It is a figure explaining the effect of the converter device by Embodiment 1 of this invention using a comparative example. It is a figure explaining operation | movement of the converter apparatus by Embodiment 2 of this invention. It is a figure which shows the main circuit structure of the converter apparatus by Embodiment 3 of this invention. It is a figure which shows the main circuit structure of the converter apparatus by Embodiment 4 of this invention. It is a figure which shows the main circuit structure of the converter apparatus by Embodiment 5 of this invention. It is a figure which shows the main circuit structure of the converter apparatus by Embodiment 6 of this invention. It is a figure which shows the main circuit structure of the converter apparatus by another example of Embodiment 6 of this invention. It is a figure explaining the operation | movement of the converter by Embodiment 6 of this invention.

Explanation of symbols

1 SC type (switched capacitor type) converter block,
1a to 1d SC type converter block (SC type cell),
2 Low voltage side DC power supply positive terminal, 2a Low voltage side DC power supply negative terminal (grounding terminal),
3 High voltage side DC power supply positive terminal, 3a High voltage side DC power supply negative terminal (ground terminal),
10, 10a SC converter device, 12 set frequency,
Ce, Ce1 to Ce3 capacitors, Di1, Di2 first and second diodes,
Di3, Di4 first and second diodes,
Sw1 to Sw4 Switches as first to fourth semiconductor switching elements,
Sw1a, Sw2a Switches as first and second semiconductor switching elements,
Sw3a, Sw4a Switches as first and second semiconductor switching elements,
Sw100, Sw201 to Sw203, Sw301 to Sw303, Sw401 to Sw403 Switches as semiconductor switching elements,
Lr, Lr1 to Lr3 Inductors.

Claims (9)

A capacitor and a plurality of semiconductor switching elements are provided between the low voltage side DC power source and the high voltage side DC power source, and charging and discharging of the capacitor are alternately switched between the two power sources by the switching operation of the semiconductor switching element. In a DC / DC converter device that performs energy transfer at
Inserting an inductor in a path section where the charging path and discharging path of the capacitor overlap, and when charging and discharging the capacitor, the capacitor and the inductor are connected in series,
A DC / DC converter characterized in that a period of a drive signal for driving the plurality of semiconductor switching elements is changed in accordance with an amount of current flowing through the inductor so as to substantially coincide with a resonance period of the capacitor and the inductor. apparatus. A cell that includes the capacitor, the inductor, and the plurality of semiconductor switching elements between the low-voltage side DC power source and the high-voltage side DC power source and performs energy transfer between the two power sources, n ( n is an integer of 2 or more) connected in parallel, and driving signals for driving the semiconductor switching elements in each cell are shifted in phase by 2π / n between the cells. The DC / DC converter apparatus according to claim 1. The plurality of semiconductor switching elements are:
Both terminals are connected to the first semiconductor switching element having one terminal connected to the positive terminal of the high-voltage side DC power supply, the other terminal of the first semiconductor switching element and the positive terminal of the low-voltage side DC power supply. , A third semiconductor switching element having one terminal connected to the negative terminal of the high-voltage DC power supply and the negative terminal of the low-voltage DC power supply, the third A fourth semiconductor switching element having both terminals connected to the other terminal of the semiconductor switching element and a positive terminal of the low-voltage DC power source,
A series body in which the capacitor and the inductor are connected in series is configured, and a connection point between the first and second semiconductor switching elements and a connection point between the third and fourth semiconductor switching elements are connected in series. Connect through the body,
The simultaneous conduction of the second and third semiconductor switching elements and the simultaneous conduction of the first and fourth semiconductor switching elements are alternately performed, and charging and discharging of the capacitor are alternately switched. Item 3. The DC / DC converter device according to Item 1 or 2. The plurality of semiconductor switching elements are:
Both terminals are connected to the first semiconductor switching element having one terminal connected to the positive terminal of the high-voltage side DC power supply, the other terminal of the first semiconductor switching element and the positive terminal of the low-voltage side DC power supply. , A third semiconductor switching element having one terminal connected to the negative terminal of the high-voltage DC power supply and the negative terminal of the low-voltage DC power supply, the third A fourth semiconductor switching element having both terminals connected to the other terminal of the semiconductor switching element and a terminal on the low-voltage side DC power supply side of the second semiconductor switching element,
Connecting the connection point between the first and second semiconductor switching elements and the connection point between the third and fourth semiconductor switching elements via the capacitor;
Inserting the inductor between the positive terminal of the low-voltage DC power supply and the connection point between the second and fourth semiconductor switching elements;
The simultaneous conduction of the second and third semiconductor switching elements and the simultaneous conduction of the first and fourth semiconductor switching elements are alternately performed, and charging and discharging of the capacitor are alternately switched. Item 3. The DC / DC converter device according to Item 1 or 2. A first diode connected to the positive terminal of the high-voltage side DC power source, a cathode terminal connected to the anode terminal of the first diode, and an anode terminal connected to the positive terminal of the low-voltage side DC power source A connected second diode;
The plurality of semiconductor switching elements are:
A first semiconductor switching element having one terminal connected to the negative terminal of the high-voltage side DC power supply and the negative terminal of the low-voltage side DC power supply; the other terminal of the first semiconductor switching element; and the low voltage A second semiconductor switching element having both terminals connected to the positive electrode terminal of the side DC power supply,
A series body in which the capacitor and the inductor are connected in series is configured, and a connection point between the first and second diodes and a connection point between the first and second semiconductor switching elements are connected to the series body. Connect through
The first semiconductor switching element and the second semiconductor switching element are alternately turned on to alternately switch the charge and discharge of the capacitor, and energy is transferred from the low voltage side DC power source to the high voltage side DC power source. The DC / DC converter device according to claim 1 or 2, wherein A first diode connected to the positive terminal of the high-voltage side DC power source, a cathode terminal connected to the anode terminal of the first diode, and an anode terminal connected to the positive terminal of the low-voltage side DC power source A connected second diode;
The plurality of semiconductor switching elements are:
A first semiconductor switching element having one terminal connected to the negative terminal of the high-voltage side DC power source and the negative terminal of the low-voltage side DC power source; the other terminal of the first semiconductor switching element; and the second terminal A second semiconductor switching element having both terminals connected to the anode terminal of the diode,
A connection point between the first and second diodes and a connection point between the first and second semiconductor switching elements are connected via the capacitor;
Inserting the inductor between the positive terminal of the low-voltage side DC power source and the connection point between the second diode and the second semiconductor switching element;
The first semiconductor switching element and the second semiconductor switching element are alternately turned on to alternately switch the charge and discharge of the capacitor, and energy is transferred from the low voltage side DC power source to the high voltage side DC power source. The DC / DC converter device according to claim 1 or 2, wherein The anode terminal is connected to the negative terminal of the high voltage side DC power source and the negative terminal of the low voltage side DC power source, the anode terminal is connected to the cathode terminal of the first diode, and the cathode terminal is A second diode connected to the positive terminal of the low voltage side DC power supply,
The plurality of semiconductor switching elements are:
Both terminals are connected to the first semiconductor switching element having one terminal connected to the positive terminal of the high-voltage side DC power supply, the other terminal of the first semiconductor switching element and the positive terminal of the low-voltage side DC power supply. A second semiconductor switching element connected to
A series body in which the capacitor and the inductor are connected in series is configured, and a connection point between the first and second diodes and a connection point between the first and second semiconductor switching elements are connected to the series body. Connect through
The first semiconductor switching element and the second semiconductor switching element are alternately turned on to alternately switch charging and discharging of the capacitor, and energy is transferred from the high voltage side DC power source to the low voltage side DC power source. The DC / DC converter device according to claim 1 or 2, wherein The anode terminal is connected to the negative terminal of the high voltage side DC power source and the negative terminal of the low voltage side DC power source, the anode terminal is connected to the cathode terminal of the first diode, and the cathode terminal is A second diode connected to the positive terminal of the low voltage side DC power supply,
The plurality of semiconductor switching elements are:
Both terminals are connected to the first semiconductor switching element having one terminal connected to the positive terminal of the high-voltage side DC power supply, the other terminal of the first semiconductor switching element, and the cathode terminal of the second diode. A second semiconductor switching element connected,
A connection point between the first and second diodes and a connection point between the first and second semiconductor switching elements are connected via the capacitor;
Inserting the inductor between the positive terminal of the low-voltage side DC power source and the connection point between the second diode and the second semiconductor switching element;
The first semiconductor switching element and the second semiconductor switching element are alternately turned on to alternately switch charging and discharging of the capacitor, and energy is transferred from the high voltage side DC power source to the low voltage side DC power source. The DC / DC converter device according to claim 1 or 2, wherein A plurality of series bodies in which the capacitor and the inductor are connected in series are provided between the low-voltage side DC power source and the high-voltage side DC power source, and the plurality of series switching units are switched by the switching operation of the plurality of semiconductor switching elements. A first mode in which a body is simultaneously connected in parallel between both terminals of the low voltage side DC power supply, and the plurality of series bodies are simultaneously connected in series to the low voltage side DC power supply, and the series connected composite series body 2. The DC / DC according to claim 1, wherein switching between charging and discharging of the plurality of capacitors at the same time is performed by alternately switching between a second mode in which both are connected in parallel between both terminals of the high-voltage side DC power source. Converter device.

Images