JP3370522B2 - Boost type bridge inverter circuit and control method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-up bridge inverter circuit suitable for generating a high-voltage or large-capacity output from a DC input power source having a relatively low voltage, and a control method for limiting the DC input voltage.

[0002]

2. Description of the Related Art Conventionally, when a relatively high-capacity high voltage is generated by using a 24V or 48V battery power source as an input, or when a large-capacity power conversion is performed in a facility that can obtain only 100V or 200V AC, it is low. Switching current increases with voltage, power loss of semiconductor devices,
The power loss of the transformer increases and the efficiency of the inverter decreases.

Particularly when a high voltage is generated, the number of turns of the transformer is increased and the efficiency is reduced. Therefore, in FIG.
As shown in, the booster circuit BS is provided in the preceding stage of the inverter INV.
T is connected and the voltage of the DC input power supply E is boosted to about twice, and then four times the power supply voltage, for example, 200 V for a 48V power supply.
In a 100 V power source for V and AC, power conversion is performed by a bridge inverter INV including switching elements Q1 to Q4 such as FETs or IGBTs having a withstand voltage of 500 V and anti-parallel diodes D1 to D4 anti-parallel connected to these.

[0004]

However, in such a conventional step-up bridge inverter, a power converter such as a step-up circuit is separately required, so that the size is large and the cost is high, which is economical. Not. In particular, there is a drawback that the control circuit has two systems and becomes complicated.

The present invention has been made in view of such conventional problems, and solves the above problems by providing a bridge type inverter device having a self-boosting function with a simple configuration. With the goal.

[0006]

According to a first aspect of the present invention, in order to solve the above-mentioned problems, a step-up bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up bridge inverter, In a circuit that includes a resonance capacitor and operates a step-up bridge inverter to resonate the resonance inductor and the resonance capacitor to supply power to a load, the step-up bridge inverter is
First arm A1 to fourth arm A each including a switching element and an anti-parallel diode anti-parallel to the switching element
4 is connected to a bridge and is located above and below the first
The first boost inductor is connected between the connection point T3 between the arm A1 and the third arm A3 and the positive electrode of the DC input power supply, and the second arm A2 and the fourth arm A4 located above and below are connected. A second step-up inductor is connected between the connection point T4 and the positive electrode of the DC input power supply, and the connection point T1 between the first arm A1 and the second arm A2 located on the left and right, and the connection point T1 located on the left and right. An energy bank capacitor is connected between the connection point T2 between the third arm A3 and the fourth arm A4,
The configuration is such that a boosted AC output is taken out between the connection point T3 and the connection point T4, and the energy bank capacitor is boosted and charged by the first and second boost inductors, the switching element, and the antiparallel diode. A step-up bridge inverter circuit characterized by the above.

In order to solve the above-mentioned problems, the invention according to claim 2 is provided with a step-up half-bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the boost half-bridge inverter, and a resonance capacitor. A circuit for supplying electric power to a load by causing the resonance inductor and the resonance capacitor to resonate by operating the step-up half-bridge inverter, wherein the step-up half-bridge inverter is a switching element and an antiparallel antiparallel circuit. A first arm A1 and a second arm A2 each including a diode, and a third arm A3 and a fourth arm A4 each including an energy bank capacitor are connected to a bridge, and are positioned vertically. Between the connection point T3 between the first arm A1 and the third arm A3 and the positive electrode of the DC input power supply A voltage inductor is connected, the connection point T4 between the second arm A2 and the fourth arm A4 located above and below and the negative electrode of the DC input power supply are connected, and the voltage is boosted from between the connection point T3 and the connection point T4. The present invention provides a step-up bridge inverter circuit, which is configured to take out an AC output and is characterized in that a step-up inductor, a switching element, and an antiparallel diode step-up charge an energy bank capacitor.

In order to solve the above-mentioned problems, the invention according to claim 3 is the same as the invention according to claim 1 or 2, wherein a boost inductor, a first arm A1 and a second arm A2 are provided. The present invention provides a step-up bridge inverter circuit characterized in that a commutation diode is connected in series with a connection point T1.

In order to solve the above-mentioned problems, a fourth aspect of the present invention is the invention according to any one of the first to third aspects, in which the boost inductor and the connection point T3 and / or
Alternatively, the present invention provides a step-up bridge inverter circuit in which a separating diode is connected in series between the connecting point T4.

In order to solve the above-mentioned problems, a fifth aspect of the present invention includes a step-up bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up bridge inverter, and a resonance capacitor, The step-up bridge inverter includes a first arm A1 to a fourth arm each including a switching element and an antiparallel diode antiparallel thereto.
Of the first arm A1 and the third arm A3 which are formed by connecting the arm A4 of the first arm A3 to the bridge and are connected to the bridge.
And a positive electrode of the DC input power source, the first boost inductor is connected between the second arm A2 and the fourth arm A4, which are located above and below, and the positive electrode of the DC input power source. 2 boost inductors are connected to connect the first arm A1 and the second arm
An energy bank capacitor is connected between the connection point T1 with the arm A2 and the connection point T2 with the third arm A3 and the fourth arm A4, and the voltage is boosted from between the connection point T3 and the connection point T4. In the control method that takes out the AC output and operates the step-up bridge inverter to resonate the resonance inductor and the resonance capacitor to supply the boosted electric power to the load, the DC input by turning the switching element on and off. From power supply to first and second
Of a boosted bridge inverter circuit, in which magnetic energy is stored in a boosted inductor, and the energy bank capacitor is boosted and charged by this magnetic energy and the voltage of a DC input power source, and a boosted AC output is supplied. It provides a control method of.

In order to solve the above-mentioned problems, the invention according to claim 6 comprises a step-up half-bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up half-bridge inverter, and a resonance capacitor. The step-up half-bridge inverter includes a first arm A1 and a second arm A2 each having a switching element and an anti-parallel diode anti-parallel thereto, and a third arm A3 and an third arm A3 each having an energy bank capacitor. 4 arm A4 is connected to the bridge, and the first
Connecting point T3 between the arm A1 and the third arm A3 and the positive electrode of the DC input power source are connected to the connecting point T3 between the first arm A1 and the third arm A3 through the boost inductor, and the negative electrode of the DC input power source is connected. To the third arm A3 and the fourth arm A
4 is connected to the connection point T2 with the connection point 4 and the boosted AC output is taken out from between the connection points T3 and T4.
In the control method of operating the step-up bridge inverter to resonate the resonance inductor and the resonance capacitor to supply the boosted power to the load, the switching element is turned on and off to transfer the magnetic energy from the DC input power supply to the boost inductor. A method of controlling a step-up bridge inverter circuit characterized by storing and then boosting and charging an energy bank capacitor with this magnetic energy and the voltage of a DC input power supply, and supplying a boosted AC output. Is.

In order to solve the above-mentioned problems, the invention according to claim 7 is the invention according to claim 5 or 6, wherein the current flowing through the antiparallel diode is connected to the boost inductor and the connection point T3 and / or The present invention provides a method for controlling a step-up bridge inverter circuit, which is characterized in that it flows through a commutation diode connected in series with a connection point T4.

In order to solve the above-mentioned problems, the invention according to claim 8 is the invention according to any one of claims 5 to 7, wherein boosting charging, which is an input voltage of a bridge inverter or a half-bridge inverter, is performed. The voltage of the energy bank capacitor is detected, the photo coupler is turned on / off by the output signal of the first error amplifier by comparing it with the first reference voltage, and the light receiving circuit of this photo coupler is connected to the input terminal of the first comparator. The voltage of a predetermined sawtooth wave is input to the other input terminal of the first comparator, the output signal of the first comparator is input to one input terminal of the AND circuit, and The output voltage is detected and compared with the second reference voltage, and the output signal of the error amplifier is input to the input terminal of the second comparator. The output signal of the gate circuit is input to the other input terminal of the AND circuit, the output signal of the AND circuit is input to one input terminal of the gate circuit, and the other input terminal of the gate circuit is connected from the flip-flop circuit to the gate circuit. The pulse signal that determines the polarity of is input, the semiconductor switch is turned on and off by the output signal from the gate circuit, and during the constant period, the first comparator outputs the output signal with a substantially constant maximum pulse width, which causes fluctuations in the output voltage. On the other hand, the pulse width is modulated by the output signal of the second comparator,
A method for controlling a step-up bridge inverter circuit, wherein the first comparator outputs an output signal having a small pulse width and controls so as to reduce the pulse width when the load is short-circuited or lightly loaded. Is.

[0014]

FIG. 1 is a diagram for explaining a first embodiment of the present invention, in which a switching element of a bridge inverter circuit having a step-up function is PWM-controlled so that the DC voltage of the inverter circuit is reduced. PWM that boosts the voltage between the input terminals above the voltage of the DC input power supply and at the same time supplies power to the load side in the same way as a normal inverter circuit
1 shows a controlled series resonant converter.

In FIG. 1, E is a DC input power source including a battery or a rectifier for rectifying commercial AC power, and Q.
1 to Q4 are switching elements formed of power semiconductor elements such as FETs or IGBTs, and D1 to D4 are diodes connected in antiparallel to the respective switching elements.
In the case of ET, since the body diode of the FET is usually used, it can be omitted. This bridge inverter configuration is obtained by connecting the first to fourth arms A1 to A4 to the bridge with each antiparallel connection circuit of the diodes D1 to D4 corresponding to the switching elements Q1 to Q4 as one arm.

Between the DC terminals of the bridge configuration, that is, the connection point T1 between the upper first arm A1 and the second arm A2
And a connection point T2 between the lower third arm A3 and the fourth arm A4, a large-capacity energy bank capacitor C1 such as an electrolytic capacitor is connected as an energy bank. Between the connection point T3 between the arm A1 and the third arm A3 and the connection point T4 between the second arm A2 and the fourth arm A4, that is, between the AC terminals, the resonance inductor LO, the series resonance capacitor CO, and Voltage transformer TF,
A rectifier circuit BD, a smoothing capacitor CS, and a load RL are connected.

Next, the step-up inductor L1 and / or the step-up inductor L2, which is a feature of the present invention, is connected to the positive electrode of the DC input power source E and the connection point T which is an AC terminal in a bridge configuration.
3 and T4, which are respectively connected to form a bridge inverter circuit integrated with a boosting function.

The switching elements Q1 to Q4 are normally PWM-controlled by a control circuit CC such as a switching regulator control IC so as to keep the output voltage constant. Here, the switching element Q of the upper arms A1 and A2
1 and Q2 normally operate in the same ON period as the ON periods of the switching elements Q3 and Q4 of the lower arms A3 and A4, and have a frequency substantially equal to the resonance frequency mainly determined by the resonance inductor LO and the parallel resonance capacitor CO. Take action.

The switching elements Q1 to Q4 perform switching operation with a pair of Q1 and Q4 and Q2 and Q3 as shown in FIG. 3, similarly to a normal bridge inverter. For example, when switching elements Q2 and Q3 are on, these switching elements are turned on with substantially the same pulse width,
The off operation is performed, and the energy of the energy bank capacitor C1 is supplied to the load side, and the energy is stored in the boost inductor L1 from the DC input power source E. Then, if energy of the boost inductor L1 and energy is also accumulated in the boost inductor L2 during a period in which all the switching elements Q1 to Q4 are off, the energy is stored in the energy bank capacitor C through the separating diodes D5 and D6.
It is released to 1 to charge it.

Similarly, when the switching elements Q1 and Q4 are on, the energy of the energy bank capacitor C1 is supplied to the load side, and the energy is stored in the boost inductor L2 from the DC input power source E. Then, when all the switching elements Q1 to Q4 are off, the energy of the boost inductor L2 and the energy stored in the boost inductor L1 are stored in the energy bank capacitor C1 through the separating diodes D5 and D6. It is released and charges it. In this way, the energy bank capacitor C1 acts as an energy bank, and its DC voltage is converted into AC and supplied to the load side. This AC voltage is supplied to the primary winding of the transformer TF through the resonance inductance LO and the parallel resonance capacitor CO, and the AC voltage generated in the secondary winding is rectified by the rectifier circuit B.
It is converted into direct current by D and the smoothing capacitor CS and supplied to the load RL. That is, the switching elements Q1 to Q
4 is PWM-controlled so as to keep the output voltage of the converter circuit constant, as in a normal bridge inverter circuit.

FIG. 2 is an equivalent circuit of FIG. The inverter circuit of FIG. 1 includes boost inductors L1 and L2, boost switching elements Q3 ′ and Q4 ′, and a commutation diode D.
It is considered to be equivalent to a combination of two booster circuits 1'and D2 'and a bridge inverter.

Inverters in the circuit of FIG. 1 also serve as components with dashes. That is, the boosting switching elements Q3 'and Q4' are also used by the switching elements Q3 and Q4 of the lower arms A3 and A4. Also, the commutation diode D
The antiparallel diodes D1 and D2 of the switching elements Q1 and Q2 of the upper arms A1 and A2 also serve as 1'and D2 '.

In the circuit of FIG. 1, the inverter circuit simultaneously performs the boosting operation. When the switching element Q3 of the lower arm A3 is turned on, the exciting current flows from the DC input power source E through the step-up inductor L1, the separating diode D5 and the switching element Q3, and the step-up inductor L3.
1 stores magnetic energy.

Next, when the switching element Q3 is turned off, the magnetic energy of the boost inductor L1 is changed to the diode D.
The energy bank capacitor C1 is charged via 5, 5 and D1. After the switching element Q3 is turned off, the switching element Q4 is turned on this time, and an exciting current flows from the DC input power source E through the boost inductor L2, the separating diode D6 and the switching element Q4, and the boost inductor L
2 stores magnetic energy. When the switching element Q4 is turned off, the magnetic energy charges the energy bank capacitor C1 via the diodes D6 and D2.

In such an inverter, the duty cycle of each switching element is less than 50% at the maximum, and therefore, by integrating the booster circuit with the inverter as in this circuit, the duty cycle of each switching element is 50%. %, The energy stored in the boost inductor L1 or L2 can be discharged for a long time.

Explaining the boosting action with the equivalent circuit shown in FIG. 2, the voltage applied to the boosting inductor L1 or L2 during the ON period of the switching element Q3 ′ or Q4 ′, that is, the voltage of the DC input power source E is VI, and the boosting operation is performed. Output voltage of circuit section, that is, energy bank capacitor C1
Let VO be the voltage across the switching element Q3 '.
Alternatively, the voltage applied to the boost inductor L1 or L2 during the off period of Q4 'is (VO-VI). Therefore,
When the inductance of the step-up inductor L1 or L2 is L, when the current flowing through the step-up inductor L1 or L2 is continuous, in the steady state, the ON period TON and the OFF period TOF are set.
Since the amount of change in the current flowing through the boosting inductor L1 or L2 of F is equal, VI.multidot.TON / L = (VO-VI) .multidot.TOF
F / L, and the output voltage VO becomes VO = (TON
+ TOFF) VI / TOFF.

Assuming that the duty cycle of the switching element Q3 'or Q4' is approximately 50%, VO = (0.
5 + 0.5) VI / 0.5 = 2VI, so that when the current is in a steady state, the output voltage VO is equal to the power supply voltage V
The voltage is boosted to almost twice as high as I. This means that if the duty cycle of the inverter is almost 50%,
It is shown that the DC input voltage applied between the DC input terminals T1 and T2 of the inverter circuit becomes about twice the power supply voltage VI.

Next, in FIG. 1, tentatively, the boosting inductors L1 and L2 are shared and only one, for example, L1 is connected, and the anode of the separating diode D6 is connected to the connection point between the boosting inductor L1 and the separating diode D5. in case of,
Since the power on both sides of the bridge inverter must be supplied by one boost inductor L1, it becomes difficult to secure the time for discharging the stored energy, and the input voltage of the inverter becomes several times the power supply voltage, and at the same time, Since the power supply current increases, it is generally not preferable for a power supply using a commercial power supply as an input source.

For example, if the duty cycle of the switching element Q3 ′ or Q4 ′ described in FIG. 2 is 45%, the duty cycle of the current supplied to the single boost inductor L1 is 90%, VO
= (0.9 + 0.1) VI / 0.1 = 10VI,
When the input is AC100V, the output voltage is 1000V
Therefore, it is not practical when the commercial AC voltage is used without being stepped down. However, as in the case of portable electronic devices, it can be seen that it may be suitable when a storage battery or a battery is used as a DC input power source with a low DC input voltage.

FIG. 4 is a diagram for explaining the second embodiment of the present invention. In such a booster type inverter circuit, the voltage across the energy bank capacitor C1 may be considerably higher than the rated load when the load is short-circuited or opened. Therefore, it is necessary to suppress an increase in the inverter input voltage when the load is short-circuited or opened, and this embodiment includes a control circuit to which a voltage limiting function for the inverter input voltage is added. The main circuit is the same as that in FIG. 1, so description thereof will be omitted.

The voltage across the energy bank capacitor C1 which is the inverter input voltage is detected by the voltage dividing resistor R1 and the voltage detecting resistor R2. The error amplifier AP1 compares the detected voltage with the reference voltage of the reference voltage source E1,
The error voltage is given to the photocoupler P through the resistor R3. In the steady state, the detection voltage of the voltage across the energy bank capacitor C1 is lower than the reference voltage of the reference voltage source E1, so the photocoupler P does not turn on. Therefore, one input terminal of the first comparator CM1 has a resistor A high level input voltage is provided through R4. Comparator C
M1 compares its high level input voltage with a sawtooth wave generated by a control circuit (not shown), and outputs a first pulse signal having a substantially constant maximum pulse width in a steady state.

On the other hand, the output voltage detection signal of the DC-DC converter is detected by the voltage dividing resistor R5 and the voltage detecting resistor R6, and the second error amplifier AP2 outputs the output detection voltage and the reference voltage of the reference voltage source E2. By comparison, the error amplified signal is given to one input terminal of the second comparator CM2. The second comparator CM2 compares the error amplification signal with the sawtooth wave voltage and outputs a pulse width modulation signal.
This pulse width modulation signal is used for the first and second gate circuits G
It is applied to one input terminal of each of the input terminals 1 and G2, and is also applied to one input terminal of the AND circuit AD.

The AND circuit AD includes a pulse signal having a substantially constant maximum pulse width from the first comparator CM1.
AND logic is applied to the pulse width modulation signal from the second comparator CM2, and a pulse signal having a pulse width depending on the overlapping width of those signals is output to the third and fourth gate circuits G3,
The voltage is applied to one of the input terminals of G4.

A rectangular pulse is applied from the flip-flop circuit FF to the other input terminal of each of the input terminals of the gate circuits G1, G2, G3, G4. Regarding the polarity of the pulse supplied from the flip-flop circuit FF, the gate circuits G1 and G2, the gate circuits G3 and G4 have opposite polarities, and the gate circuits G1 and G3, and the gate circuits G2 and G4 have the same polarities. Gate circuits G1, G2, G3
G4 receives the pulse width modulation signal and the pulse as described above, and outputs the drive signal as shown in FIG. 3 to the switching element Q1.
To Q4 respectively.

As can be seen from the above, in the steady state, the detected voltage across the capacitor C1 is the reference voltage source E1.
Since the comparator CM1 outputs a pulse signal having a substantially constant maximum pulse width, the switching elements Q1 and Q2 are substantially PWM-controlled by the output error signal so as to keep the output constant. The switching elements Q3 and Q4 perform a switching operation with substantially equal pulse widths in synchronization with the switching elements Q2 and Q1, respectively.

Next, if the inverter input voltage exceeds the reference voltage of the reference voltage source E1 by the short circuit or the light load, the inverter input voltage exceeds the reference voltage of the set voltage, that is, the voltage across the energy bank capacitor C1, the error amplification of the error amplifier AP1. The signal increases and the photocoupler P conducts, increasing the current in the light emitting diode of the photocoupler P and turning on its light receiving transistor. As a result, a current flows from the voltage source (+ 15V) through the resistor R4 and the light receiving transistor of the photocoupler P, and the collector voltage thereof decreases. Due to this decrease in the collector voltage, the input terminal voltage to the first comparator CM1 decreases, and the pulse width of the pulse signal output from the first comparator CM1 decreases. That is, the pulse width of the pulse signal output from the first comparator CM1 is reduced so that the voltage across the energy bank capacitor C1 is maintained at the limit value. As the time width of the output pulse of the first comparator CM1 is limited, the time width of the drive signal output from the gate circuits G3 and G4 is limited as shown by the chain line to the solid line in FIG. As a result, the ON time of the switching elements Q3 and Q4 is limited, and the rise of the inverter input voltage is suppressed. The conditions for selecting the set limit voltage are a voltage equal to or higher than the inverter input voltage Vo at the rated load, and a voltage that can maintain the rated output voltage even when there is no load.

Next, in another embodiment shown in FIG. 5, when MOSFETs are used as the switching elements Q1 to Q4, commutation diodes D7 and D8 are provided in order to reduce the load on the body diodes D1 and D2 of the MOSFETs. It is provided separately. By flowing the magnetic energy stored in the boost inductor L1 or L2 to the energy bank capacitor C1 through the commutation diode D7 or D8 provided outside without using the body diode of the MOSFET or hardly using it, It reduces the load on the MOSFET.

Further, the commutation diode D7 is a MOS
By connecting the diode Q8 across the FET Q1 and the separating diode D5 and across the MOSFET Q2 and the separating diode D6, the boosting energy flows through the diodes D7 and D8. Therefore, the boosting inductor L1 or L2 is connected. Since the magnetic energy stored in the capacitor does not flow through the separating diodes D5 and D6, their power loss can be reduced. In FIG. 5, the same symbols as those shown in FIG. 1 indicate corresponding members.

Next, as another embodiment of the present invention,
As shown in FIG. 6, a half bridge inverter may be used. In this case, between the DC input power source E and the connection point T3 between the switching elements Q1 and Q2 connected to the energy bank capacitors C1 and C2 so as to form a half bridge, the boost inductor L and the separation diode D are provided.
Connect the series connection with. A step-up circuit is constituted by the switching element Q2 of the half-bridge inverter, the diode D1 antiparallel to the switching element Q1, the separation diode D, and the step-up inductor L. Since the circuit operation is considered to be almost the same as that of the bridge inverter described above, the description thereof will be omitted. Since it is a half bridge, only one boost inductor is required.

The operation of this circuit will be briefly described. It is assumed that the energy bank capacitors C1 and C2 acting as a capacitor bank are charged to a predetermined voltage. First, when the switching element Q2 is turned on, the energy of the energy bank capacitor C2 is transferred to the primary winding of the transformer TF, the resonance inductor L0, and the connection point T.
It is discharged in a closed circuit composed of 3 and the switching element Q2 and supplied to the load side. At this time, a current flows from the DC input power source E through the boost inductor L, the separation diode D, the connection point T3 and the switching element Q2, and magnetic energy is stored in the boost inductor L.

When the switching element Q2 is turned off, the magnetic energy stored in the boosting inductor L flows through the energy bank capacitors C1 and C2 and the DC input power source E through the antiparallel diode D1 which is antiparallel to the switching element Q1. The bank capacitors C1 and C2 are charged. Next, when the switching element Q1 is turned on, the energy stored in the energy bank capacitor C1 is discharged through the switching element Q1, the connection point T3, the resonance inductor L0, the primary winding of the transformer TF, and the connection point T4. Supplied to the load side. With this circuit configuration, the voltage between the connection points T1 and T2 can be easily made higher than the voltage of the DC input power source E.

Here, the energy bank capacitor C
The charging path of No. 1 is a positive electrode of the DC input power source E → step-up inductor L → separation diode D → anti-parallel diode D1 → capacitor C1 → C2 → a loop composed of the negative electrode of the DC input power source E, and the positive electrode of the DC input power source E → Step-up inductor L → separation diode D → anti-parallel diode D1 → capacitor C1 → transformer TF primary winding → resonance inductor L0
-> Switching element Q2-> two circuits of a loop composed of the negative electrode of the DC input power source E.

Further, the energy bank capacitor C2
The charging path of is the positive electrode of the DC input power supply E → the boost inductor L
→ Separation diode D → Antiparallel diode D1 → Capacitor C1 → C2 → Loop consisting of negative pole of DC input power supply E and positive pole of DC input power supply E → Boost inductor L → Separation diode D → Connection point T3 → Resonance inductor L0
→ The primary winding of the transformer TF → The capacitor C2 → The loop of two loops consisting of the negative pole of the DC input power source E. Therefore, sufficient charging energy for the energy bank capacitors C1 and C2 is ensured.

When a semiconductor device such as an IGBT, a thyristor, or a bipolar transistor that does not have a body diode is used as the switching elements Q1 to Q4, it is necessary to separately connect a diode in antiparallel with each of the switching elements Q1 to Q4. There is.

Further, as the form of the inverter circuit, a series resonance type circuit using frequency control for output control can also be applied. In this case, the frequency modulation function and the PWM function can be used together in the input voltage limiting circuit. is there.

Further, the separating diode is necessary when the inductance value of the boost inductor is small, but when the inductance value is relatively large, even if omitted, it does not adversely affect the circuit.

[0047]

As described above, the present invention provides a bridge inverter circuit integrated with a boosting function for boosting a relatively low power supply voltage and converting it into an alternating current with a simple structure. As a result, the power loss can be reduced and the cost can be reduced.

Further, since it has the function of limiting the DC input voltage of the bridge inverter, it is possible to protect the circuit components of the bridge inverter from damage even during a short circuit or a light load.

The booster-function-integrated inverter circuit according to the present invention can reduce input harmonics in the same manner as an inverter circuit including a conventional booster circuit in the preceding stage.
Improve power factor.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a first embodiment of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of the first exemplary embodiment of the present invention.

FIG. 3 is a diagram for explaining another embodiment of the present invention.

FIG. 4 is a waveform diagram for explaining an embodiment of the present invention.

FIG. 5 is a diagram for explaining another embodiment of the present invention.

FIG. 6 is a diagram for explaining another embodiment of the present invention.

FIG. 7 is a diagram for explaining a conventional example.

[Explanation of symbols]

E ... DC input power supply D1 to D4 ... Anti-parallel diode LO ... Resonant inductor TF ... trance CS: Smoothing capacitor L1, L2 ... Boost inductor CC ... Control circuit Q1-Q4 ... Switching element C1 ... Energy bank capacitor CO… Parallel resonance capacitor BD ... Rectifier circuit RL ... load D5, D6 ... Separation diode D7, D8 ... Diodes for commutation D1 ', D2' ... Commutation diode Q3 ', Q4' ... Step-up switching element G1, G2, G3, G4 ... Gate circuit A1, A2, A3, A4 ... Arms that form a bridge

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI H02M 7/5387 H02M 7/5387 Z (58) Fields investigated (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 3 / 28 H02M 3/335 H02M 7/06 H02M 7/5387

Claims (8)

(57) [Claims] 1. A step-up bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up bridge inverter, and a resonance capacitor. The step-up bridge inverter is operated to operate the resonance inductor and the resonance inductor. In the circuit for supplying electric power to a load by resonating a resonance capacitor, the step-up bridge inverter includes a first arm A1 to a fourth arm A4 each including a switching element and an antiparallel diode antiparallel thereto. The first arm A1 and the third arm which are connected to the bridge and are located above and below
A first step-up inductor is connected between a connection point T3 with the arm A3 and the positive electrode of the DC input power source, and a connection point T4 with the second arm A2 and the fourth arm A4 located above and below. A second boost inductor is connected between the positive electrode of the DC input power supply and the first arm A1 located on the left and right.
And a connection point T1 between the second arm A2 and a connection point T2 between the third arm A3 and the fourth arm A4 located on the left and right, and an energy bank capacitor is connected between the connection point T1 and the second arm A2. A configuration is provided in which a boosted AC output is taken out between a point T3 and the connection point T4, and the energy bank capacitor is formed by the first and second boost inductors, the switching element, and the antiparallel diode. Step-up bridge inverter circuit characterized by step-up charging. 2. A resonance type inductor comprising a step-up half-bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up half-bridge inverter, and a resonance capacitor. In the circuit for resonating the resonance capacitor and the resonance capacitor to supply electric power to the load, the step-up half-bridge inverter includes a first arm A1 and a second arm A1 each including a switching element and an anti-parallel diode anti-parallel thereto. Arm A2 and third arm A each having an energy bank capacitor
3 and a fourth arm A4 are connected to a bridge, and between a connection point T3 between the first arm A1 and the third arm A3 located above and below and the positive electrode of the DC input power source. A connection point T4 between the second arm A2 and the fourth arm A4, which are connected to the boost inductor and are located above and below.
Is connected to the negative electrode of the DC input power source, and the connection point T3
And a connection point T4 between which the boosted AC output is taken out, wherein the energy bank capacitor is boosted and charged by the boost inductor, the switching element, and the antiparallel diode. Step-up bridge inverter circuit. 3. The step-up bridge inverter circuit according to claim 1, wherein the step-up inductor and a connection point T1 between the first arm A1 and the second arm A2 are connected to each other. Step-up bridge inverter circuit characterized by connecting commutation diodes in series. 4. The boosting bridge inverter circuit according to claim 1, wherein a separating diode is connected in series between the boosting inductor and the connection point T3 and / or the connection point T4. A boosted bridge inverter circuit characterized in that 5. A step-up bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up bridge inverter, and a resonance capacitor, wherein the step-up bridge inverter includes a switching element and an antiparallel circuit. A first arm A1 to a fourth arm A4, each of which includes an anti-parallel diode, are connected to a bridge, and a connection point T3 between the first arm A1 and the third arm A3 located above and below and A first boost inductor is connected between the positive electrode of the DC input power supply and a connection point T4 between the second arm A2 and the fourth arm A4 located above and below and the positive electrode of the DC input power supply. A second step-up inductor is connected to the connection point T1 between the first arm A1 and the second arm A2, and a connection point between the third arm A3 and the fourth arm A4. 2 is a configuration in which an energy bank capacitor is connected between the two, and a boosted AC output is taken out between the connection point T3 and the connection point T4. By operating the step-up bridge inverter, the resonance inductor and the In a control method of resonating a resonance capacitor and supplying boosted power to a load, magnetic energy is stored in the first and second boost inductors from the DC input power source by turning on and off the switching element, A method of controlling a step-up bridge inverter circuit, comprising: boosting and charging the energy bank capacitor with the magnetic energy and the voltage of the DC input power source, and supplying a boosted AC output. 6. A step-up half-bridge inverter connected to a DC input power source, a resonance inductor connected to the AC side of the step-up half-bridge inverter, and a resonance capacitor, wherein the step-up half-bridge inverter includes a switching element and an inverse thereof. A first arm A1 and a second arm A2 each having a parallel anti-parallel diode, and a third arm A3 having an energy bank capacitor, respectively.
And a fourth arm A4 are connected to a bridge, and a connection point T3 between the first arm A1 and the third arm A3 located above and below, and the positive electrode of the DC input power source are passed through a boost inductor to It is connected to a connection point T3 between the first arm A1 and the third arm A3, and the negative electrode of the DC input power source is connected to the third arm A3 and the fourth arm A4.
Is connected to a connection point T2 of the resonance inductor and the resonance capacitor by operating the step-up bridge inverter from the connection point T3 and the connection point T4. In a control method of supplying power boosted to a load by resonating with, the magnetic energy is stored in the boost inductor from the DC input power source by turning on and off the switching element, and then the magnetic energy and the DC input are stored. A method of controlling a step-up bridge inverter circuit, characterized in that the energy bank capacitor is boost-charged with a voltage of a power supply and a boosted AC output is supplied. 7. The method of controlling a boost bridge inverter circuit according to claim 5, wherein the current flowing through the antiparallel diode is supplied to the boost inductor and the connection point T3 and / or the connection point T4. A method of controlling a step-up bridge inverter circuit, characterized in that the current is passed through a commutation diode connected in series between the two. 8. The method for controlling a boosting bridge inverter circuit according to claim 5, wherein the boosting-charged energy bank capacitor is the input voltage of the bridge inverter or the half bridge inverter. The voltage is detected and compared with the first reference voltage to turn on / off the photocoupler by the output signal of the first error amplifier, and the light receiving circuit of the photocoupler is input to the input terminal of the first comparator, A voltage of a predetermined sawtooth wave is input to the other input terminal of the first comparator, the output signal of the first comparator is input to one input terminal of the AND circuit, and the output voltage to the load is detected. , The input signal of the output of the error amplifier compared to the second reference voltage is input to the input terminal of the second comparator, and the output signal of the second comparator is output. The signal is input to the other input terminal of the AND circuit, the output signal of the AND circuit is input to one input terminal of the gate circuit, and the other input terminal of the gate circuit is input from the flip-flop circuit to the polarity of the gate circuit. Inputting a pulse signal that determines the output voltage of the gate circuit, turning on and off the semiconductor switch by the output signal from the gate circuit, and during the constant time, the first comparator sends out an output signal having a substantially constant maximum pulse width, and fluctuations in the output voltage. In order to reduce the pulse width, the pulse width is modulated by the output signal of the second comparator, and when the load is short-circuited or the load is light, the first comparator outputs an output signal having a small pulse width to reduce the pulse width. A method for controlling a step-up bridge inverter circuit, which is characterized in that: