CN218570083U

CN218570083U - Novel full-bridge inverter switching circuit

Info

Publication number: CN218570083U
Application number: CN202221946844.1U
Authority: CN
Inventors: 许真剑
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-07-27
Filing date: 2022-07-27
Publication date: 2023-03-03
Anticipated expiration: 2032-07-27

Abstract

The utility model discloses a novel full-bridge inverter switch circuit, it includes: the system comprises a full-bridge inversion base circuit, a control circuit, an energy recovery circuit, a connection unit and a drive circuit; the energy recovery circuit is divided into a non-isolated recovery circuit and an isolated recovery circuit, and the driving circuit is used for driving the switching tubes in the control circuit and the full-bridge inverter basic circuit; the zero current turn-off of the control switch tube is prevented from being damaged under the condition of overload; through zero current and voltage on-off, high frequency can be obtained when the component uses the IGBT, so that two-level PFC can be used at the front end, and the cost is reduced; the front end PFC circuit can be combined to form a single-stage AC/DC conversion circuit, and compared with the existing full-bridge soft switch, the requirement on input voltage change is reduced.

Description

Novel full-bridge inverter switching circuit

Technical Field

The utility model relates to the power electronics field especially involves a novel full-bridge inverter switch circuit.

Background

The full-bridge inverter circuit and its soft switch are generally used in high-power high-frequency devices, such as: switching power supply, induction heating equipment, electric welding machine, direct current fill electric pile etc..

The current common inversion methods include: single ended flyback, single ended forward, push-pull, half bridge, full bridge, etc., and related topologies of the above circuits. The main function of the soft switch is to replace the traditional hard switch, namely a switching tube (silicon controlled rectifier, mos tube, igbt and the like), because the hard switch is easy to burn out when working at high frequency and the waste of electric energy is serious.

Soft switching means zero voltage on and zero current off. Some components are added in the circuit, and meanwhile, the switching tube is controlled by a driving signal to manufacture a zero-voltage or zero-current state, so that the switching tube is switched on and off in the state, and further, the loss of the switching tube is greatly reduced.

In the existing full-bridge inversion soft switching circuit, the highest voltage borne by a full-bridge switching tube is close to twice of the input voltage, and the cost of a high-grade voltage-resistant switching tube required to be used is higher; then, the overcurrent of a control switch tube in the soft switch circuit is the sum of the primary side current of the load inductor/transformer and the current of the energy storage capacitor, and the current loss needs to be further reduced; when the load exceeds the maximum current allowed by the design, the charging voltage of the energy storage capacitor cannot exceed the input voltage, so that the soft switching circuit fails to be changed into a hard switching circuit, and the overload protection in the conventional full-bridge inverter switching circuit cannot realize zero-current turn-off without damaging a switching tube in the soft switching circuit.

A general high-power supply product is a two-stage AC/DC conversion circuit, namely PFC + DC/DC. The switch tube and part of elements of PFC and DC/DC are combined and multiplexed to be called a single-stage AC/DC conversion circuit, so that the cost is greatly reduced. However, because there is no proper full-bridge soft switching circuit, the hard-switching single-stage AC/DC conversion circuit can only do small power.

Accordingly, there is a need for a new full bridge inverter switching circuit that addresses one or more of the above problems.

SUMMERY OF THE UTILITY MODEL

In order to solve one or more problems existing in the prior art, the utility model provides a novel full-bridge inverter switch circuit. The utility model discloses a solve the technical scheme that above-mentioned problem adopted and be: a novel full-bridge inverter switching circuit comprises: a full-bridge inverter base circuit; the control circuit is provided with a first loop circuit, and the first loop circuit at least comprises a first control switch tube, a first control diode and a first capacitor;

the energy recovery circuit is a non-isolated recovery circuit or an isolated recovery circuit, the energy recovery circuit is connected with the second control switch tube in series and is marked as an energy control circuit, and the energy control circuit is connected with the control circuit in parallel;

the energy control circuit and the control circuit are combined and recorded as a soft switching circuit, and the soft switching circuit is electrically connected to the front end or the rear end of the full-bridge inverter basic circuit;

the soft switch circuit is electrically connected with the full-bridge inverter basic circuit through the connecting unit;

the driving circuit is electrically connected with the soft switching circuit and is used for controlling a switching tube in the soft switching circuit;

the soft switch circuit is electrically connected to the rear end of the full-bridge inverter basic circuit, the soft switch circuit is electrically connected to the front end through the auxiliary diode, the soft switch circuit is electrically connected to the front end of the full-bridge inverter basic circuit, and the soft switch circuit is electrically connected to the rear end through the auxiliary diode.

Further, the isolated recovery circuit is provided with a transformer, a second loop circuit is arranged at the input end of the transformer, the second loop circuit at least comprises an input winding, an eleventh capacitor and an eleventh diode of the transformer, an eleventh resistor is connected in parallel to the eleventh capacitor and is marked as a third loop circuit, a fourth loop circuit is arranged at the output end of the transformer, the fourth loop circuit at least comprises an output winding, a twenty-first diode and a twenty-first capacitor of the transformer, and the fourth loop circuit is electrically connected with a load or a control power supply;

when the energy recovery circuit is the isolated recovery circuit, the second control switch tube is connected in series with the second loop circuit.

Furthermore, the non-isolated recovery circuit is provided with a first inductor, the first inductor is connected in series with the second control switch tube, the first inductor is connected in series with the second diode, the second control switch tube is connected in parallel with the second diode, and the second control switch tube, the second diode and the first capacitor form a fifth loop.

Further, the input end can be an alternating current input, and an LC low-pass filter circuit can be electrically connected into the input end.

Furthermore, the input end is a three-phase alternating current input, and three single phases form a three-phase AC/DC conversion circuit.

Further, the input end can be a three-phase input, and a three-phase LC low-pass filter circuit can be electrically connected in the input end.

Further, the three single-phase inputs are connected in parallel with each other through capacitors.

Further, when the energy recovery circuit is an isolated recovery circuit, the input end may be a three-phase alternating current input, the auxiliary diode is connected in parallel with the auxiliary capacitor to form a sixth loop, the sixth loop is connected in series with the auxiliary inductor, and the auxiliary inductor is electrically connected to the input end.

The utility model discloses the beneficial value who gains is: the utility model discloses a be in the same place full-bridge contravariant basic circuit, control circuit, energy recuperation circuit, drive circuit and inside other loop electricity connection, realized reducing the withstand voltage grade of full-bridge switch tube, and then reduce cost, if: when the three-phase PFC outputs 800V, a voltage-resistant switching tube can be used in 1200V grade; the overcurrent of a switching tube in the soft switching circuit is the primary side current of the load inductor/transformer, so that the overcurrent output by the energy storage capacitor is reduced, and the current loss is further reduced; the zero current turn-off function of a control switch in the soft switching circuit cannot be damaged due to overload; the full-bridge switching tube is switched on and off at zero current and voltage, so that high frequency can be obtained when the IGBT is used, and a PFC circuit with two levels can be used at the front end, so that the cost is reduced; compared with the existing full-bridge soft switch, the requirement on the change of the input voltage is reduced, the technical scheme is free of requirement, the requirement of a front-end circuit is further reduced, and a switching tube in the soft switching circuit can normally work within the change range from 0 to Vd (input voltage maximum). The utility model discloses a practical value has greatly improved above.

Drawings

FIG. 1 is a schematic diagram of an isolated recovery circuit according to the present invention;

FIG. 2 is a schematic diagram of an application of the non-isolated recovery circuit of the present invention;

FIG. 3 is a schematic diagram of an application of the three-phase input and isolated recovery circuit of the present invention;

FIG. 4 is a schematic diagram of the application of the three-phase PFC input circuit and the isolated recovery circuit of the present invention;

FIG. 5 is a schematic diagram of the application of the three-phase PFC input circuit and the non-isolated recovery circuit of the present invention;

FIG. 6 is a schematic diagram of an application of the three-phase input and non-isolated recovery circuit of the present invention;

FIG. 7 is a timing diagram of waveforms associated with the use of the schematic diagram of FIG. 1.

[ reference numerals ]

10. Energy recovery circuit

20. A connection unit.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The invention may be embodied in many other forms without departing from the spirit or essential characteristics thereof, and it should be understood that the invention is not limited to the embodiments disclosed herein.

As shown in fig. 1-6, the utility model discloses a novel full-bridge inverter switch circuit, include: a full-bridge inverter base circuit; the control circuit is provided with a first loop circuit, and the first loop circuit at least comprises a first control switch tube V0, a first control diode D01 and a first capacitor C0;

the energy recovery circuit 10 is a non-isolated recovery circuit or an isolated recovery circuit, the energy recovery circuit 10 is connected with a second control switch tube Q0 in series and is marked as an energy control circuit, and the energy control circuit is connected with the control circuit in parallel;

the soft switching circuit comprises a connecting unit 20, wherein the connecting unit 20 is a lead or a connecting inductor L0, and the soft switching circuit is electrically connected with a full-bridge inverter basic circuit through the connecting unit 20;

the driving circuit is electrically connected with the soft switching circuit and is used for controlling switching tubes in the soft switching circuit, and the driving circuit controls 6 switching tubes (matched in time sequence) to be V0, Q0, V1, V2, V3 and V4;

soft switch circuit electricity is when full-bridge contravariant basic circuit rear end, soft switch circuit passes through auxiliary diode D and front end electric connection, soft switch circuit electric connection is when full-bridge contravariant basic circuit front end (not given in the picture), soft switch circuit passes through auxiliary diode D and rear end electric connection.

It should be noted that the full bridge inverter base circuit is a conventional circuit, and an inductor L may be disposed therein or a transformer B1 may be disposed to be connected to the output.

Specifically, as shown in fig. 1, the isolated recovery circuit is provided with a transformer B2, an input end of the transformer B2 is provided with a second loop circuit, the second loop circuit at least comprises an input winding 1-2 of the transformer, an eleventh capacitor C11 and an eleventh diode D11, the eleventh capacitor C11 is connected in parallel with an eleventh resistor R11 and is denoted as a third loop circuit, an output end of the transformer is provided with a fourth loop circuit, the fourth loop circuit at least comprises an output winding 3-4 of the transformer, a twenty-first diode D21 and a twenty-first capacitor C21, and the fourth loop circuit is electrically connected with a load or a control power supply;

when the energy recovery circuit 10 is the isolated recovery circuit, the second control switch Q0 is connected in series with the second loop circuit.

Specifically, as shown in fig. 2, the non-isolated recovery circuit is provided with a first inductor L01, the first inductor L01 is connected in series with a second control switch tube Q0, the first inductor L01 is connected in series with a second diode D02, the second control switch tube Q0 is connected in parallel with the second diode D02, and the second control switch tube Q0, the second diode D02 and a first capacitor C01 form a fifth loop.

Because the inverter can work in the range of input voltage (0-Vd), the novel full-bridge inverter switching circuit can realize high-power single-stage AC/DC conversion.

Specifically, as shown in fig. 3, when the energy recovery circuit 10 is an isolated recovery circuit, the input end may be an AC input, the input end is connected to an LC low-pass filter circuit (Lr-Cr), and under the cooperation of a control signal, a single-stage AC/DC conversion circuit is formed, and the PFC and the DC/DC are combined; in fig. 3, L and C belong to auxiliary components, and are intended to slow down the rising and falling speeds of the primary voltage and current of the load transformer B1, and further reduce the influence of the secondary reflected voltage on the quality of the PFC, but L and C increase the stress of the on-off of the switching tube, so the values of L and C must be small or directly removed, which needs to be determined according to the influence of the secondary reflected voltage. When the input end is three-phase alternating current input, three circuits shown in the figure 3 can be connected in parallel to form a single-stage three-phase AD/DC conversion circuit.

Specifically, as shown in fig. 4 and 5, the energy recovery circuit 10 is an isolated or non-isolated recovery circuit, the input end of the energy recovery circuit may be a three-phase power supply, and the input end of the energy recovery circuit is electrically connected to three LC low-pass filters (Lr-Cr), and then is electrically connected to the main circuit to form a single-stage three-phase AC/DC conversion circuit, i.e., a three-phase single-switch PFC and a full-bridge DC/DC converter.

Specifically, as shown in fig. 6, when the energy recovery circuit 10 is a non-isolated recovery circuit, the input end may be an AC input, and the input end is electrically connected to an LC low-pass filter circuit (Lr-Cr), and then electrically connected to the main circuit, and under the coordination of the control signal, a single-stage AC/DC circuit is formed, and the PFC and the DC/DC circuit are combined; when the input end is three-phase alternating current input, three circuits shown in the figure 6 can be connected in parallel to form a three-phase AD/DC conversion circuit.

It should be noted that, as shown in fig. 3 and 4, the input end may be a three-phase ac input, the auxiliary diode D is connected in parallel with the auxiliary capacitor C to form a sixth loop, the sixth loop is connected in series with the auxiliary inductor L, and the auxiliary inductor L is electrically connected to the input end.

As shown in fig. 1, the full-bridge alternating-current direction is switched by the timing sequence coordination of 6 switching tubes V0, Q0, V1, V2, V3, and V4, and the on-off of the four switching tubes V1, V2, V3, and V4 are performed under the condition that the input is cut off by V0, so that the switching loss is 0; moreover, since V0 is also soft switching on and off, the switching loss of the whole circuit is further reduced, and a smaller switching tube can be selected. Therefore, although a switch tube is added to the main circuit, the cost of the main circuit is still lower than that of a full-bridge circuit with hard switches, the circuit can be operated at higher frequency through extremely low switching loss, the size of a magnetic core and the number of turns of a load inductor/transformer can be further reduced, and the cost is saved.

As shown in fig. 1, when V0 is turned on, since the V0 to V4 switching tubes have inter-electrode capacitance, the freewheeling diodes thereof have reverse recovery current, and the load inductor or the transformer has distributed capacitance. If they are all bigger, V0 has bigger direct current at the moment of opening, increasing the switching loss. Therefore, the V0 zero voltage can be turned on only by connecting the inductor L0 in series. And L0 has few turns, so that the distributed capacitance can be ignored.

If the capacitance between the poles of the switching tube is very small, the reverse recovery of the freewheeling diode is instantaneous and ultrafast, and the load inductance or the distributed capacitance of the transformer is also small. L0 can be made very small and can even be eliminated, which reduces the stress experienced when V0 is turned off, as the case may be. When V0 is switched on, the current of a load inductor or a transformer is zero, and the induced electromotive force generated by the load inductor or the transformer and preventing the current from suddenly increasing is equal to Vd, so that V0 obtains zero voltage conduction.

As shown in fig. 1 and 5, Q0 is turned on immediately after the switching tube V0 is turned on. And the flyback switching power supply composed of the Q0, the transformer B2 and the like feeds back the electric quantity stored in the C0 to a load or a control power supply. The energy output by B2 is only related to the capacity of C0 and is not related to the conduction time of V0, and the energy can be independently used as a power supply of some circuit after voltage stabilization. After Q0 is conducted, C0 is discharged through the primary winding of B2 and Q0, and Q0 is turned off after C0 is discharged. When the switch tube V0 is turned off, the capacitor C0 is discharged, and the voltage is zero. Therefore, in the turn-off process of the switching tube V0, the borne current is transferred to charge the C0, and the zero-current turn-off is realized.

It is also noted that Q0 may also be turned on a little bit before V0. That is, Q0 is turned on within a few hundred microseconds before V0 is turned on. Thus, B2 can absorb the through current generated by the inter-switching-transistor capacitance, the freewheeling diode reverse current, the distributed capacitance, and the like, and is more beneficial to the conduction of V0. L0 may be reduced or even eliminated. But this slightly reduces the PWM duty cycle of V0. Although only a few hundred nanoseconds, there is a certain effect when the frequency is high and the PWM period is small. So whether Q0 is turned on earlier than V0, as the case may be.

In the working process, the highest voltage born by the main circuit switching tubes V0-V4 is Vd. The cutoff voltage of V0 is equal to Vd plus the voltage generated by the power-off of inductor L0. The inductance of L0 is much smaller than the load inductance, so the resulting voltage is not large, and the cutoff voltage of V0 can be considered to be substantially equal to Vd. And the current flowing through V0 is equal to the current in the load inductor or the primary side of the transformer.

The output power is regulated by PWM on/off V0. The switching of the full bridges V1 to V4 is fixed from this time to the next time t. When the load is large, after V0 is turned off, hundreds of nanoseconds are formed, the energy of a load coil or a transformer can be completely released, the primary side current becomes 0, the full bridges V1-V4 can perform zero-current and zero-voltage switching, the switching is performed for hundreds of nanoseconds, and then V0 can be turned on again after the zero-current and zero-voltage switching is completed. When the load is not large, the energy of the load coil or the transformer is released for a long time, but V0 is closed early under light load, the conduction time Ton is small, the closing time Toff is large, and the load coil or the transformer has enough time to release the energy. Therefore, the on-time Ton of V0 can be adjusted between 0 and (t-1 uS), that is, when the full-bridge frequency reaches 100K, the circuit still obtains a higher duty ratio of 80%.

In a power supply product with a three-phase 380ACV input, the front end of the full bridge circuit is a three-phase PFC, and the three-phase PFC has two-level output and three-level output. The two-level voltage is high, and a MOSFET having a withstand voltage of 650V or less, which is the best overall performance, cannot be used, and the IBGT has a large switching loss and cannot obtain a high operating frequency. In order to obtain high frequency by the rear-end full-bridge DC/DC, the front end adopts three-level PFC, but the circuit control of the three-level PFC is complicated, the rear-end full-bridge DC/DC adopts MOSFET switches to be connected in series, the control is also complicated, and moreover, the cost of the three-level PFC is higher than that of the two-level PFC. In the full-bridge soft switching circuit of the technical scheme, the four switching tubes of the full bridge are switched on and off at zero current and zero voltage, high frequency can be obtained by using the IGBT, and therefore the front end can use the two-level PFC, and the cost is reduced.

With reference to fig. 3 and 6, the full-bridge soft switching circuit according to the present disclosure can operate in a variation range of the input voltage from 0 to Vd, and does not affect the soft switching of 5 switching transistors. Therefore, the waveform of the AC input sinusoidal voltage of the power grid is introduced, and the waveform, the feedback output voltage and the feedback input average current together control the PWM driving of V0, so that the function of PFC can be realized at the same time, and the waveform of the input current is changed along with the change of the power supply voltage. Namely, the combination of PFC and full-bridge DC/DC becomes a single-stage AC/DC conversion circuit, thereby greatly reducing the cost.

To sum up, the utility model discloses a be in the same place full-bridge contravariant basic circuit, control circuit, energy recuperation circuit, drive circuit and inside other loop electricity connection, realized reducing the withstand voltage grade of full-bridge switch tube, and then reduce cost, if: when the three-phase PFC outputs 800V, a voltage-resistant switching tube can be used in 1200V grade; the overcurrent of a switching tube in the soft switching circuit is the primary side current of the load inductor/transformer, so that the overcurrent output by the energy storage capacitor is reduced, and the current loss is further reduced; the zero current turn-off function of a control switch in the soft switching circuit cannot be damaged due to overload; the full-bridge switching tube is switched on and off at zero current and voltage, so that high frequency can be obtained when the IGBT is used, and a PFC circuit with two levels can be used at the front end, so that the cost is reduced; compared with the existing full-bridge soft switch, the requirement on the change of the input voltage is reduced, the technical scheme is free of requirement, the requirement of a front-end circuit is further reduced, and a switching tube in the soft switching circuit can normally work within the change range from 0 to Vd (input voltage maximum). The utility model discloses a practical value has greatly improved above.

The embodiments described above merely represent one or more embodiments of the present invention, which are described in detail and concrete, but cannot be understood as limitations of the present invention. It should be noted that, for those skilled in the art, without departing from the concept of the present invention, several variations and modifications can be made, which all fall within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A novel full-bridge inverter switching circuit comprises: the full-bridge inverter basic circuit is characterized by comprising a control circuit, wherein the control circuit is provided with a first loop, and the first loop at least comprises a first control switch tube, a first control diode and a first capacitor;

2. The novel full-bridge inverter switch circuit according to claim 1, wherein the isolated recovery circuit is provided with a transformer, the input end of the transformer is provided with a second loop circuit, the second loop circuit at least comprises an input winding, an eleventh capacitor and an eleventh diode of the transformer, the eleventh capacitor is connected in parallel with an eleventh resistor and is marked as a third loop circuit, the output end of the transformer is provided with a fourth loop circuit, the fourth loop circuit at least comprises an output winding, a twenty-first diode and a twenty-first capacitor of the transformer, and the fourth loop circuit is electrically connected with a load or a control power supply;

3. The novel full-bridge inverter switch circuit according to claim 1, wherein the non-isolated recovery circuit is provided with a first inductor, the first inductor is connected in series with the second control switch tube, the first inductor is connected in series with a second diode, the second control switch tube is connected in parallel with the second diode, and the second control switch tube, the second diode and the first capacitor form a fifth loop.

4. The novel full-bridge inverter switch circuit according to claim 1, wherein the input terminal is an ac input, and the LC low-pass filter circuit is electrically connected to the input terminal.

5. The novel full-bridge inverter switching circuit according to claim 4, wherein the input terminal is a three-phase AC input, and three single phases form a three-phase AC/DC conversion circuit.

6. The novel full-bridge inverter switching circuit according to claim 1, wherein the input terminal is a three-phase input, and a three-phase LC low-pass filter circuit is electrically connected to the input terminal.

7. The novel full-bridge inverter switching circuit according to claim 6, wherein three single-phase inputs are connected in parallel with each other through capacitors.

8. The novel full-bridge inverter switch circuit according to claim 1, wherein when the energy recovery circuit is an isolated recovery circuit, the input terminal is a three-phase ac input, the auxiliary diode is connected in parallel with an auxiliary capacitor to form a sixth loop, the sixth loop is connected in series with an auxiliary inductor, and the auxiliary inductor is electrically connected to the input terminal.