JP5070937B2 - Boost chopper circuit, step-down chopper circuit, and DC-DC converter circuit using the same - Google Patents

Description

  The present invention relates to a step-up chopper circuit, a step-down chopper circuit, and a DC-DC converter circuit using the step-up chopper circuit.

  FIG. 10 is a configuration diagram showing a conventional chopper circuit capable of bidirectional operation, and shows a configuration similar to that described in Patent Document 1. In FIG. In FIG. 10, 29 is a reactor, 30A and 31A are semiconductor switches composed of IGBTs, 30D and 31D are diodes, and 32 is a smoothing capacitor. The chopper circuit having the configuration shown in FIG. 10 can operate in a bidirectional mode, that is, in a step-up mode and a step-down mode.

  FIG. 11 is a block diagram showing a boost mode in a conventional chopper circuit. The chopper circuit shown in FIG. 11 shows a circuit in which an input DC power supply 34 is connected between circuit terminals 33A and 33B and a load 36 is connected between circuit terminals 35A and 35B in FIG. In FIG. 11, the semiconductor switch 30A is turned on / off based on a duty ratio determined by the voltage V of the DC power supply 34 and the voltage E between the circuit terminals 35A and 35B. That is, the semiconductor switch 30A is on / off controlled so that the voltage E between the circuit terminals 35A and 35B is constant. The current route when the semiconductor switch 30A is turned on and the current route when the semiconductor switch 30A is turned off are in a state indicated by a broken line and an alternate long and short dash line in FIG. 11, respectively. The semiconductor switch 31A is fixed in an off state in order to operate as a free wheel diode.

  FIG. 12 is a block diagram showing a step-down mode in a conventional chopper circuit. The chopper circuit shown in FIG. 12 shows a circuit in which a load 36 is connected between circuit terminals 33A and 33B and an input DC power supply 34 is connected between circuit terminals 35A and 35B in FIG. In FIG. 12, the semiconductor switch 31A is turned on / off based on a duty ratio determined by the voltage E of the DC power supply 34 and the voltage V between the circuit terminals 33A and 33B. That is, the semiconductor switch 31A is on / off controlled so that the voltage V between the circuit terminals 33A and 33B is constant. The current route when the semiconductor switch 31A is turned on and the current route when the semiconductor switch 31A is turned off are in a state indicated by a broken line and a one-dot chain line in FIG. 12, respectively. The semiconductor switch 30A is fixed in an off state in order to operate as a free wheeling diode.

  FIG. 13 is a diagram showing a switching pattern in a conventional chopper circuit. Here, FIG. 13A shows a switching pattern of the chopper circuit (boost mode) shown in FIG. 11, and FIG. 13B shows a switching pattern of the chopper circuit (step-down mode) shown in FIG. As shown in FIG. 13, a gate signal for the semiconductor switch 30A or 31A is generated based on the comparison between the command signal and the triangular wave carrier signal.

  In the boost mode, the semiconductor switch 30A is turned on / off by the gate signal shown in FIG. 13A, and the current route shown in FIG. 11 is formed as described above. When the semiconductor switch 30A is turned on, the voltage V of the DC power supply 34 is applied to the reactor 29, and the reactor current increases. Thereafter, when the semiconductor switch 30A is turned off, a voltage of (VE), which is the difference between the voltage V of the DC power supply 34 and the voltage E on the secondary side, is applied to the reactor 29, and the reactor current decreases.

  On the other hand, in the step-down mode, the semiconductor switch 31A is turned on / off by the gate signal shown in FIG. 13B, and the current route shown in FIG. 12 is formed as described above. When the semiconductor switch 31A is turned on, a voltage (EV), which is the difference between the voltage E of the DC power supply 34 and the secondary side voltage V, is applied to the reactor 29, and the reactor current increases. Thereafter, when the semiconductor switch 31A is turned off, the voltage V of the DC power supply 34 is applied to the reactor 29, and the reactor current decreases.

  Here, the amplitude Δi of the ripple current of the reactor 29 in the boost mode is expressed by the following equation.

(Equation 1)
Δi = V / (L · fs) × (1−V / E)
L is the inductance value of the reactor 29, and fs is the switching frequency of the semiconductor switch 30A.
Similarly, the amplitude Δi of the ripple current of reactor 29 in the step-down mode is expressed by the following equation.

(Equation 2)
Δi = (E−V) / (L · fs) × V / E

  From the above equations 1 and 2, it can be seen that the magnitude of the ripple current of the reactor 29 is inversely proportional to the switching frequency fs and the inductance value L. Therefore, from the above formulas 1 and 2, in order to reduce the ripple current of the reactor 29, a method of reducing the voltage applied to the reactor 29, a method of increasing the switching frequency fs, and a method of increasing the inductance value L of the reactor 29 Can be considered.

JP 2002-369505 A

  Conventional chopper circuits and DC-DC converters including those described in Patent Document 1 have a limit in reducing the reactor ripple current by an inexpensive method without increasing loss. That is, the above three methods can be considered to reduce the ripple current of the reactor. First, the method of reducing the voltage applied to the reactor has a problem that the applied voltage is determined in a circuit. . Further, when the switching frequency fs is increased, there are problems that the switching loss in the semiconductor switch increases and the iron loss in the reactor increases. Further, when the inductance value L of the reactor is increased, there is a problem that the reactor becomes large and expensive.

  Further, in the conventional circuit configuration, the semiconductor switch is required to have a withstand voltage higher than the circuit voltage, so that the semiconductor switch is expensive.

  The present invention has been made to solve the above-described problems, and its object is to reduce the reactor ripple current without increasing the loss in a semiconductor switch or the like, and to reduce the size and cost. A step-up chopper circuit, a step-down chopper circuit, and a DC-DC converter circuit using the step-up chopper circuit can be provided.

The step-up chopper circuit according to the present invention includes a first reactor having a first terminal and a third terminal, a second reactor having a second terminal and a fourth terminal, a first terminal and a second terminal. an input DC power source connected between the terminals of the third terminal and the fourth first diode connected in series between the terminals of the load, a second diode, a connection point of the first diode and the load, And a first smoothing capacitor and a second smoothing capacitor connected in series between the connection point of the load and the second diode, a connection point of the third terminal and the first diode, and the first smoothing capacitor and the second smoothing capacitor. A first switch connected between the connection points of the two smoothing capacitors, a connection point between the first smoothing capacitor and the second smoothing capacitor, and a connection point between the second diode and the fourth terminal. Second second , A third diode connected in parallel to the first switch, and a fourth diode connected in parallel to the second switch, wherein the first switch is on and the second switch is When in the off state, a current path is formed from the input DC power source to the input DC power source via the first reactor, the first switch, the second smoothing capacitor, the second diode, and the second reactor in order, when the first switch is turned off and the second switch is turned on, the first reactor from the input DC power source, a first diode, via the first smoothing capacitor, a second switch, a second reactor sequentially Thus, a current path returning to the input DC power supply is formed.

The step-down chopper circuit according to the present invention includes a first reactor having a first terminal and a third terminal, a second reactor having a second terminal and a fourth terminal, a first terminal and a second terminal. a load connected between the terminals of the first switch connected in series between the third terminal and a fourth terminal, the input DC power source, a second switch, the first parallel-connected to the first switch 1 diode, a second diode connected in parallel to the second switch, a connection point between the first switch and the input DC power supply, and a connection point connected in series between the connection point of the input DC power supply and the second switch The first smoothing capacitor, the second smoothing capacitor, the connection point of the third terminal and the first switch, and the third diode connected between the connection point of the first smoothing capacitor and the second smoothing capacitor And the first smoothing Connection point of the capacitor and the second smoothing capacitor, and a second switch and a fourth diode connected between the connection point of the fourth terminal, comprising a first switch is turned on and the second switch When is turned off, a current path is formed from the first smoothing capacitor to the first smoothing capacitor via the first switch, the first reactor, the load, the second reactor, and the fourth diode in this order. When the first switch is off and the second switch is on, the second smoothing capacitor sequentially passes through the third diode, the first reactor, the load, the second reactor, and the second switch. Thus, a current path returning to the second smoothing capacitor is formed.

  A DC-DC converter circuit according to the present invention includes the boost chopper circuit, an error amplifier that outputs a difference voltage between an output voltage applied to a load and a reference voltage thereof, and a pulse based on the output of the error amplifier. A pulse width modulation circuit that outputs a pulse subjected to width modulation, and a control circuit that controls the operation of the first switch and the second switch based on the output of the pulse width modulation circuit.

  A DC-DC converter circuit according to the present invention includes the step-down chopper circuit, and further includes an error amplifier that outputs a difference voltage between an output voltage applied to a load and a reference voltage thereof, and an output of the error amplifier. A pulse width modulation circuit that outputs a pulse width modulated pulse, and a control circuit that controls the operation of the first switch and the second switch based on the output of the pulse width modulation circuit. .

  According to the present invention, it is possible to reduce the ripple current of the reactor without increasing the loss in the semiconductor switch or the like, and it is possible to configure the apparatus at a small size and at low cost.

  In order to explain the present invention in more detail, it will be described with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a chopper circuit according to Embodiment 1 of the present invention. In FIG. 1, 1 is a reactor, 2A, 2B, 3A, 3B are semiconductor switches composed of IGBTs, etc., 2AD, 2BD, 3AD, 3BD are diodes connected in parallel to the semiconductor switches 2A, 2B, 3A, 3B, 4A and 4B are smoothing capacitors having a DC voltage of E / 2.

  Here, the smoothing capacitors 4A and 4B are connected in series. A circuit in which the semiconductor switches 2A and 3A are connected in series is connected to both ends of the smoothing capacitor 4A, and a connection point between the semiconductor switches 2A and 3A is connected to the terminal 1a of the reactor 1. A circuit in which the semiconductor switches 2B and 3B are connected in series is connected to both ends of the smoothing capacitor 4B, and a connection point between the semiconductor switches 2B and 3B is connected to the terminal 1b of the reactor 1. In addition, 5 has shown the neutral point. The circuit terminals 6A and 6B are connected to terminals 1c and 1d of the reactor 1, and the circuit terminals 7A and 7B are connected to terminals on both sides of the smoothing capacitors 4A and 4B connected in series, respectively.

Next, the operation of the chopper circuit having the above configuration will be described.
FIG. 2 is a block diagram showing a boost mode of the chopper circuit according to the first embodiment of the present invention. The boost chopper circuit shown in FIG. 2 shows a circuit in which an input DC power supply 8 is connected between circuit terminals 6A and 6B in FIG. 1, and a load 9 is connected between circuit terminals 7A and 7B. Reference numeral 10 denotes a reactor current, and the semiconductor switches 3A and 3B are fixed in an off state.

  That is, in the step-up chopper circuit, the terminals 1 c and 1 d of the reactor 1 are connected to both terminals of the DC power supply 8. Further, when the semiconductor switches 3A and 3B are turned off, the reactor 1, the diode 3AD, the load 9, and the diode 3BD are connected in series to the DC power supply 8. The series circuit of the smoothing capacitors 4A and 4B is connected between the connection point of the diode 3AD and the load 9 and the connection point of the load 9 and the diode 3BD. The series circuit of the semiconductor switches 2A and 2B is connected between the connection point of the terminal 1a of the reactor 1 and the diode 3AD and the connection point of the diode 3BD and the terminal 1b of the reactor 1. Further, the connection point of the semiconductor switches 2A and 2B and the connection point of the smoothing capacitors 4A and 4B are connected.

  The semiconductor switches 2A and 2B are automatically controlled by a control circuit (not shown) so as to perform switching alternately. The on-duty of the semiconductor switches 2A and 2B is also automatically controlled according to the boost rate. The on-duty of the semiconductor switches 2A and 2B is the same as that of the conventional boost chopper circuit in the steady state.

  FIG. 3 is a diagram for explaining the operation of the step-up chopper circuit shown in FIG. 2, and shows a current path when the on-duty of the semiconductor switches 2A and 2B is less than ½. Here, FIG. 3A shows a current route when the semiconductor switch 2A is in the on state and the semiconductor switch 2B is in the off state. In this case, a current path is formed from the DC power supply 8 to the DC power supply 8 via the reactor 1, the semiconductor switch 2A, the smoothing capacitor 4B, the diode 3BD, and the reactor 1 in this order. During this period, the reactor current 10 increases (increases).

  FIG. 3B shows a current route when both the semiconductor switches 2A and 2B are off. When the semiconductor switch 2A is turned off from the state shown in FIG. 3A, as shown in FIG. 3B, the reactor 1, the diode 3AD, the smoothing capacitor 4A, the smoothing capacitor 4B, the diode 3BD, the reactor are connected from the DC power supply 8. A current path is formed that returns to the DC power source 8 through 1 in sequence. In such a case, the energy accumulated in the reactor 1 is released, and the reactor current 10 drops (decreases).

  FIG. 3C shows a current route when the semiconductor switch 2A is in an off state and the semiconductor switch 2B is in an on state. When the semiconductor switch 2B is turned on from the state shown in FIG. 3B, as shown in FIG. 3C, the reactor 1, the diode 3AD, the smoothing capacitor 4A, the semiconductor switch 2B, and the reactor 1 are sequentially supplied from the DC power supply 8. A current path is formed that returns to the DC power source 8 via the current path. And the reactor current 10 rises during this period.

  By repeating the above operation, the smoothing capacitors 4A and 4B can be boosted. Here, FIG. 4 is a diagram showing a switching pattern of the boost chopper circuit shown in FIG. 2, and waveforms of respective parts when the above operation is performed are shown in FIG. When the on-duty is less than 1/2, the semiconductor switches 2A and 2B are alternately switched as shown in FIG. 4A, and are not turned on at the same time. Reactor current 10 rises during a period in which either one of semiconductor switches 2A and 2B is on, and falls during a period in which both semiconductor switches 2A and 2B are off. Note that the terminal voltage applied to the reactor 1 is (VE / 2) / 2 when either one of the semiconductor switches 2A and 2B is on, and when both the semiconductor switches 2A and 2B are off. The reset voltage is (VE) / 2.

  On the other hand, FIG. 4B shows the waveform of each part when the on-duty exceeds 1/2. In FIG. 4B, the reactor current 10 rises during a period in which both of the semiconductor switches 2A and 2B are turned on simultaneously, and falls during a period in which either one of the semiconductor switches 2A and 2B is turned off. The terminal voltage applied to the reactor 1 becomes V / 2 during a period in which both of the semiconductor switches 2A and 2B are on. Further, a reset voltage is applied at (V−E / 2) / 2 during a period in which either one of the semiconductor switches 2A and 2B is in an OFF state.

  Note that when the on-duty of the semiconductor switches 2A and 2B is ½, theoretically no ripple current flows and a complete DC current is obtained.

  In the step-up chopper circuit having the above-described configuration, the ripple current of the reactor 1 can be reduced without increasing the losses in the semiconductor switches 2A and 2B, and the configuration can be made small and inexpensive.

  That is, the boost chopper circuit operates so as to boost with the potential difference between the voltage V of the DC power supply 8 and the voltage E / 2 of the smoothing capacitors 4A and 4B, so that the voltage applied to the reactor 1 can be kept low. As a result, the ripple current of the reactor 1 can be reduced. Further, by alternately switching the semiconductor switches 2A and 2B, the ripple frequency of the reactor 1 becomes twice the switching frequency of the semiconductor switches 2A and 2B. For this reason, the inductance value of the reactor 1 can be made small and the small and cheap reactor 1 can be employ | adopted.

  The semiconductor switches 2A and 2B only have a voltage of E / 2. For this reason, it is possible to use a semiconductor switch having a lower withstand voltage than the conventional one. Further, since the semiconductor switches 2A and 2B are alternately switched, the switching frequency can be kept low, and further, the switching loss can be kept low because the switching is performed at the voltage E / 2.

  Here, the amplitude Δi of the ripple current of the reactor 1 in the boost chopper circuit having the above-described configuration is expressed by the following equation.

(Equation 3)
Δi = (E−V) · (2V−E) / E × 1 / (2 · L · fs)
L is the inductance value of the reactor 1, and fs is the switching frequency of the semiconductor switches 2A and 2B. Here, based on the parameter example of Table 1 below, when the ripple currents of the conventional method and the present method are compared, the ripple current Δi = 133.3 [A] of the conventional method is compared with the ripple current of the present method. Δi = 33.3 [A]. That is, in the boost chopper circuit having the above configuration, the ripple current can be reduced to about ¼ of the conventional method.

(Table 1)
Example of parameters related to ripple current Δi

Next, the operation in the step-down mode of the chopper circuit shown in FIG. 1 will be described.
FIG. 5 is a block diagram showing the step-down mode of the chopper circuit according to the first embodiment of the present invention. The step-down chopper circuit shown in FIG. 5 has a load 9 connected between circuit terminals 6A and 6B in FIG. 1, and an input DC power supply 8 (not shown in FIG. 5) connected between circuit terminals 7A and 7B. Is shown. The semiconductor switches 2A and 2B are fixed in the off state.

  That is, in the step-down chopper circuit, the terminals 1 c and 1 d of the reactor 1 are connected to both terminals of the load 9. Further, when the semiconductor switches 2A and 2B are turned off, the reactor 1, the semiconductor switch 3A, the DC power supply 8, and the semiconductor switch 3B are connected in series to the load 9. The series circuit of the smoothing capacitors 4A and 4B is connected between the connection point of the semiconductor switch 3A and the DC power supply 8 and the connection point of the DC power supply 8 and the semiconductor switch 3B. The series circuit of the diodes 2AD and 2BD is connected between the connection point of the terminal 1a of the reactor 1 and the semiconductor switch 3A and the connection point of the semiconductor switch 3B and the terminal 1b of the reactor 1. Furthermore, the connection point of the diodes 2AD and 2BD and the connection point of the smoothing capacitors 4A and 4B are connected.

  The semiconductor switches 3A and 3B are automatically controlled by a control circuit (not shown) so as to perform switching alternately. The on-duty of the semiconductor switches 3A and 3B is also automatically controlled according to the step-down rate. The on-duty of the semiconductor switches 3A and 3B is the same as that of the conventional step-down chopper circuit in a steady state.

  FIG. 6 is a diagram for explaining the operation of the step-down chopper circuit shown in FIG. 5, and shows a current path when the on-duty of the semiconductor switches 3A and 3B exceeds 1/2. Here, FIG. 6A shows a current route when the semiconductor switch 3A is in an OFF state and the semiconductor switch 3B is in an ON state. In this case, a current path is formed from the smoothing capacitor 4B to the smoothing capacitor 4B via the diode 2AD, the reactor 1, the load 9, the reactor 1, and the semiconductor switch 3B in this order. During this period, the reactor current 10 decreases (decreases).

  FIG. 6B shows a current route when both the semiconductor switches 3A and 3B are in the ON state. When the semiconductor switch 3A is turned on from the state shown in FIG. 6A, the current flows from the smoothing capacitor 4A to the semiconductor switch 3A, the reactor 1, the load 9, the reactor 1, and the semiconductor switch as shown in FIG. 6B. 3B and the flow of the smoothing capacitor 4B, the reactor current 10 rises (increases).

  FIG. 6C shows a current route when the semiconductor switch 3A is on and the semiconductor switch 3B is off. When the semiconductor switch 3B is turned off from the state shown in FIG. 6B, as shown in FIG. 6C, the semiconductor switch 3A, the reactor 1, the load 9, the reactor 1, and the diode 2BD are sequentially passed from the smoothing capacitor 4A. Thus, a current path returning to the smoothing capacitor 4A is formed. In such a case, the energy accumulated in the reactor 1 is released, and the reactor current 10 drops.

  By repeating the above operation, the step-down mode can be operated. FIG. 7 is a diagram showing a switching pattern of the step-down chopper circuit shown in FIG. 5, and waveforms of respective parts when the above operation is performed are shown in FIG. When the on-duty exceeds 1/2, the reactor current 10 rises during a period in which both the semiconductor switches 3A and 3B are turned on simultaneously, and falls during a period in which either one of the semiconductor switches 3A and 3B is turned off. To do. Note that the terminal voltage applied to the reactor 1 becomes (EV) / 2 during a period in which both the semiconductor switches 3A and 3B are on. Further, a reset voltage is applied at (E / 2−V) / 2 during a period in which either one of the semiconductor switches 3A and 3B is in an OFF state.

  On the other hand, FIG. 7A shows the waveform of each part when the on-duty is less than 1/2. When the on-duty is less than 1/2, the semiconductor switches 3A and 3B are alternately switched as shown in FIG. 7A, and are not simultaneously turned on. Reactor current 10 rises during a period in which either one of semiconductor switches 3A and 3B is on, and falls during a period in which both semiconductor switches 3A and 3B are off. Here, the terminal voltage applied to the reactor 1 is (E / 2−V) / 2 during a period when one of the semiconductor switches 3A and 3B is on, and both the semiconductor switches 3A and 3B are off. The reset voltage during the period is V / 2.

  Note that when the on-duty of the semiconductor switches 3A and 3B is ½, theoretically no ripple current flows and a complete DC current is obtained.

  In the step-down chopper circuit having the above-described configuration, the ripple current of the reactor 1 can be reduced without increasing the losses in the semiconductor switches 3A and 3B, and the configuration can be made small and inexpensive.

  That is, the step-down chopper circuit operates so as to step down the voltage E / 2 of the smoothing capacitors 4A and 4B to the potential difference between the voltage E / 2 and the output voltage V. Therefore, the voltage applied to the reactor 1 is lowered. As a result, the ripple current of the reactor 1 can be reduced. Further, by alternately switching the semiconductor switches 3A and 3B, the ripple frequency of the reactor 1 becomes twice the switching frequency of the semiconductor switches 3A and 3B. For this reason, the inductance value of the reactor 1 can be made small and the small and cheap reactor 1 can be employ | adopted.

  Note that only a voltage of E / 2 is applied to the semiconductor switches 3A and 3B. For this reason, it is possible to use a semiconductor switch having a lower withstand voltage than the conventional one. In addition, since the semiconductor switches 3A and 3B are alternately switched, the switching frequency can be kept low, and further, the switching is performed at a voltage of E / 2, so that the switching loss can be kept low.

  Here, the amplitude Δi of the ripple current of the reactor 1 in the step-down chopper circuit configured as described above is expressed by the following equation.

(Equation 4)
Δi = (E−V) · (2V−E) / E × 1 / (2 · L · fs)
L is the inductance value of the reactor 1, and fs is the switching frequency of the semiconductor switches 3A and 3B. Here, as in the step-up mode, the ripple current Δi = 133.3 [A] in the conventional method is compared between the conventional method and the present method based on the parameter example in Table 1 above. On the other hand, the ripple current Δi of this method is 33.3 [A]. That is, in the step-down chopper circuit having the above configuration, the ripple current can be reduced to about ¼ of the conventional method.

Embodiment 2. FIG.
FIG. 8 is a block diagram showing a DC-DC converter circuit according to Embodiment 2 of the present invention, and shows a control device related to the boost mode of the bidirectional chopper circuit shown in FIG. In FIG. 8, 11 is a voltage detector for detecting the voltage of the input DC power supply 8, 12 is a current detector for detecting the reactor current 10, 13 is a voltage detector for detecting the voltage of the smoothing capacitor 4A, and 14 is the smoothing capacitor 4B. Is a voltage detector for detecting the voltage of The detection signals from the voltage detectors 11, 13, 14 and the current detector 12 are sent to the controller 15.

  The controller 15 includes an error amplifier (not shown). This error amplifier receives a reference voltage of an output voltage to be applied to the load 9 and an output voltage applied to the load 9, and outputs a difference voltage (error voltage) between these two input voltages. Further, the controller 15 gives an output signal (command value) appropriately automatically controlled based on the output of the error amplifier and the reactor current 10 to the pulse width modulation circuit 16. The pulse width modulation circuit 16 outputs a pulse subjected to pulse width modulation based on the output signal from the controller 15, and appropriately controls the switch operation of the semiconductor switch 2A by a control circuit (not shown).

  The pulse width modulation circuit 16 operates the semiconductor switch 2A by comparing, for example, a carrier generator 17 for generating a triangular wave carrier and a triangular wave carrier from the carrier generator 17 with an output signal from the controller 15. And a comparator 18 that outputs a pulse to the control circuit.

  On the other hand, the output signal from the controller 15 is also supplied to the pulse width modulation circuit 19. The pulse width modulation circuit 19 outputs a pulse width modulated pulse based on the output signal from the controller 15 and appropriately controls the switch operation of the semiconductor switch 2B by a control circuit (not shown). The pulse width modulation circuit 19 compares the triangular wave carrier from the carrier generator 20 with the output signal from the controller 15 and operates the semiconductor switch 2B, for example. And a comparator 21 for outputting a pulse to the control circuit.

  Note that the phase difference of each carrier of the triangular wave carrier generators 17 and 20 has a configuration that can be freely selected. For example, a phase difference of 180 degrees is optimal for reducing the ripple current of the reactor 1. It becomes a parameter. Further, the maximum and minimum values of the triangular wave carriers of the carrier generators 17 and 20 and the frequency are made equal (within a predetermined error range) to shift the phase. By comparing with the value, the configuration of the pulse width modulation circuits 16 and 19 can be simplified.

  FIG. 9 is a diagram showing another configuration of the DC-DC converter circuit according to Embodiment 2 of the present invention, and shows a control device related to the step-down mode of the bidirectional chopper circuit shown in FIG. In FIG. 9, the voltage detector 11 is connected so as to detect the voltage of the load 9. The detection signals from the voltage detectors 11, 13, 14 and the current detector 12 are sent to the controller 22.

  The controller 22 includes an error amplifier (not shown). This error amplifier receives a reference voltage of an output voltage to be applied to the load 9 and an output voltage applied to the load 9, and outputs a difference voltage (error voltage) between these two input voltages. Further, the controller 22 gives an output signal (command value) appropriately automatically controlled based on the output of the error amplifier and the reactor current 10 to the pulse width modulation circuit 23. The pulse width modulation circuit 23 outputs a pulse width modulated pulse based on the output signal from the controller 22, and appropriately controls the switch operation of the semiconductor switch 3A by a control circuit (not shown).

  The pulse width modulation circuit 23 operates the semiconductor switch 3A by comparing, for example, a carrier generator 24 for generating a triangular wave carrier and a triangular wave carrier from the carrier generator 24 with an output signal from the controller 22. And a comparator 25 for outputting a pulse to the control circuit.

  On the other hand, the output signal from the controller 22 is also supplied to the pulse width modulation circuit 26. The pulse width modulation circuit 26 outputs a pulse-modulated pulse based on the output signal from the controller 22, and appropriately controls the switch operation of the semiconductor switch 3B by a control circuit (not shown). The pulse width modulation circuit 26 operates the semiconductor switch 3B by comparing, for example, a carrier generator 27 for generating a triangular wave carrier and a triangular wave carrier from the carrier generator 27 with an output signal from the controller 22. And a comparator 28 for outputting a pulse to the control circuit.

  The phase difference between the carriers of the triangular wave carrier generators 24 and 27 can be freely selected. For example, a 180 ° phase difference is optimal for reducing the ripple current of the reactor 1. It becomes a parameter. Further, the maximum and minimum values of the triangular wave carriers of the carrier generators 24 and 27 and the frequency are made equal (within a predetermined error range) to shift the phase. By comparing with the value, the configuration of the pulse width modulation circuits 23 and 26 can be simplified.

It is a block diagram which shows the chopper circuit in Embodiment 1 of this invention. It is a block diagram which shows the pressure | voltage rise mode of the chopper circuit in Embodiment 1 of this invention. FIG. 3 is a diagram for explaining the operation of the boost chopper circuit shown in FIG. 2. It is a figure which shows the switching pattern of the step-up chopper circuit shown in FIG. It is a block diagram which shows the pressure | voltage fall mode of the chopper circuit in Embodiment 1 of this invention. FIG. 6 is a diagram for explaining the operation of the step-down chopper circuit shown in FIG. 5. FIG. 6 is a diagram showing a switching pattern of the step-down chopper circuit shown in FIG. 5. It is a block diagram which shows the DC-DC converter circuit in Embodiment 2 of this invention. It is a figure which shows the other structure of the DC-DC converter circuit in Embodiment 2 of this invention. It is a block diagram which shows the conventional chopper circuit. It is a block diagram which shows the pressure | voltage rise mode in the conventional chopper circuit. It is a block diagram which shows the pressure | voltage fall mode in the conventional chopper circuit. It is a figure which shows the switching pattern in the conventional chopper circuit.

Explanation of symbols

1 Reactor 1a, 1b, 1c, 1d Terminal 2A, 2B, 3A, 3B Semiconductor switch 2AD, 2BD, 3AD, 3BD Diode 4A, 4B Smoothing capacitor 5 Neutral point 6A, 6B, 7A, 7B Circuit terminal 8 DC power supply 9 Load DESCRIPTION OF SYMBOLS 10 Reactor current 11, 13, 14 Voltage detector 12 Current detector 15, 22 Controller 16, 19, 23, 26 Pulse width modulation circuit 17, 20, 24, 27 Carrier generator 18, 21, 25, 28 Comparator 29 Reactor 30A, 31A Semiconductor switch 30D, 31D Diode 32 Smoothing capacitor 33A, 33B, 35A, 35B Circuit terminal 34 DC power supply 36 Load

Claims (6)

A first reactor having a first terminal and a third terminal;
A second reactor having a second terminal and a fourth terminal;
An input DC power source connected between said first terminal and said second terminal,
And the third terminal and the fourth first diode connected in series between the terminals of the load, a second diode,
A connection point of the first diode and the load, and a first smoothing capacitor and a second smoothing capacitor connected in series between the connection point of the load and the second diode;
A first switch connected between a connection point of the third terminal and the first diode, and a connection point of the first smoothing capacitor and the second smoothing capacitor;
Connection point of the first smoothing condenser and the second smoothing capacitor, and a second switch connected between the connection point of the second diode and the fourth terminal,
A third diode connected in parallel to the first switch;
A fourth diode connected in parallel to the second switch;
With
When the first switch is in an on state and the second switch is in an off state, the first direct current power source, the first switch, the second smoothing capacitor, the second diode, A current path is formed to return to the input DC power source via the second reactor in sequence,
When the first switch is in an off state and the second switch is in an on state, the input DC power source is connected to the first reactor, the first diode, the first smoothing capacitor, the second switch, A step-up chopper circuit characterized in that a current path is formed to return to the input DC power supply via the second reactor in sequence. A step-up chopper circuit according to claim 1, further comprising:
An error amplifier that outputs a difference voltage between an output voltage applied to a load and a reference voltage thereof;
A pulse width modulation circuit for outputting a pulse width modulated pulse based on the output of the error amplifier;
A control circuit for controlling the operation of the first switch and the second switch based on the output of the pulse width modulation circuit;
A DC-DC converter circuit comprising: The pulse width modulation circuit
A first carrier generator and a second carrier generator for generating triangular wave carriers;
A first comparator that compares the triangular wave carrier from the first carrier generator with a command value based on an output of an error amplifier and outputs a pulse for operating the first switch to a control circuit;
A second comparator that compares a triangular wave carrier from the second carrier generator with the command value and outputs a pulse for operating a second switch to the control circuit;
With
The triangular wave carrier from the first carrier generator and the triangular wave carrier from the second carrier generator have the same maximum value, minimum value, and frequency, and their phases are shifted. The DC-DC converter circuit according to claim 2. A first reactor having a first terminal and a third terminal;
A second reactor having a second terminal and a fourth terminal;
A load connected between the first terminal and the second terminal,
The third terminal and the first switch connected in series between the fourth terminal, the input DC power source, a second switch,
A first diode connected in parallel to the first switch;
A second diode connected in parallel to the second switch;
A connection point of the first switch and the input DC power supply, and a first smoothing capacitor and a second smoothing capacitor connected in series between the connection point of the input DC power supply and the second switch;
A third diode connected between a connection point of the third terminal and the first switch, and a connection point of the first smoothing capacitor and the second smoothing capacitor;
And the connection point of the first smoothing condenser and the second smoothing capacitor, and a fourth diode connected between the connection point of the second switch and the fourth terminal,
With
When the first switch is in the on state and the second switch is in the off state, the first switch, the first reactor, the load, the second reactor, the second A current path returning to the first smoothing capacitor via the four diodes sequentially is formed,
When the first switch is in the off state and the second switch is in the on state, the third diode, the first reactor, the load, the second reactor, A step-down chopper circuit characterized in that a current path is formed to return to the second smoothing capacitor via two switches in sequence. A step-down chopper circuit according to claim 4, further comprising:
An error amplifier that outputs a difference voltage between an output voltage applied to a load and a reference voltage thereof;
A pulse width modulation circuit for outputting a pulse width modulated pulse based on the output of the error amplifier;
A control circuit for controlling the operation of the first switch and the second switch based on the output of the pulse width modulation circuit;
A DC-DC converter circuit comprising: The pulse width modulation circuit
A first carrier generator and a second carrier generator for generating triangular wave carriers;
A first comparator that compares the triangular wave carrier from the first carrier generator with a command value based on an output of an error amplifier and outputs a pulse for operating the first switch to a control circuit;
A second comparator that compares a triangular wave carrier from the second carrier generator with the command value and outputs a pulse for operating a second switch to the control circuit;
With
The triangular wave carrier from the first carrier generator and the triangular wave carrier from the second carrier generator have the same maximum value, minimum value, and frequency, and their phases are shifted. The DC-DC converter circuit according to claim 5.

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