WO2018023882A1

WO2018023882A1 - Amplitude limit control circuit, device and method

Info

Publication number: WO2018023882A1
Application number: PCT/CN2016/102563
Authority: WO
Inventors: 徐宝华; 朱斯忠; 何智; 许向东
Original assignee: 中惠创智无线供电技术有限公司
Priority date: 2016-08-04
Filing date: 2016-10-19
Publication date: 2018-02-08

Abstract

An amplitude limit control circuit, device and method. The circuit comprises a resonant coil (L1), a resonant capacitor (C1), and a voltage controlled switch (S1). The resonant coil (L1) and the resonant capacitor (C1) are connected in series. Two switching ends of the voltage controlled switch (S1) are connected to two end points of the resonant capacitor (C1) respectively. When a stable voltage needs to be provided, the voltage controlled switch (S1) is controlled to be turned on, and the resonant capacitor (C1) is shorted. The previous resonant state of the circuit is damaged, and a stable voltage or current can be provided, so that the problem that a driven resonant ring works unstably is resolved.

Description

Limiting control circuit, device and method

Technical field

This application claims the priority of the domestic application filed on August 4, 2016, the Chinese Patent Office, the application number is 201610634350.2, and the invention name is "a limit control circuit, device and method", the entire contents of which are incorporated herein by reference. In the application.

This application claims the priority of the domestic application filed on August 4, 2016, the Chinese Patent Application No. 201620841267.8, entitled "A Limit Control Circuit and Device", the entire contents of which are incorporated herein by reference. .

This application claims the priority of the domestic application filed on August 4, 2016 by the Chinese Patent Office, Application No. 201610634335.8, entitled "A Limiting Control Circuit and Method", the entire contents of which are incorporated herein by reference. .

The present application claims priority to the Chinese Patent Application, filed on Aug. 4, 2016, Serial No. No. No. No. No. No. No. No. No. No. No. No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No No

Background technique

The driven resonant ring has the dual characteristics of receiving energy and transmitting energy. In the wirelessly powered terminal, the driven resonant ring is often used as a receiving resonant ring to supply power to the terminal.

Since the driven resonant ring operates in a resonant state, the voltage and current amplitudes in the resonant ring are large and unstable. If the terminal is directly powered, large current and voltage fluctuations will occur, which will have a serious impact on the terminal. It will even burn electrical appliances. Therefore, there is a need for a circuit that controls the amplitude of the driven resonant ring voltage or current to ensure stable operation of the driven resonant ring.

Summary of the invention

In view of this, the present invention provides a limiting control circuit, apparatus and method for solving the problem of unstable operation of a driven resonant ring.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

A limiting control circuit includes:

Resonant coil, resonant capacitor and voltage controlled switch;

The resonant coil and the resonant capacitor are connected in series; two switch ends of the voltage controlled switch are respectively connected to two end points of the resonant capacitor.

Preferably, the voltage controlled switch is a MOSFET tube, and the drain and source of the MOSFET tube are two switch ends.

Preferably, the voltage controlled switch is an IGBT tube, and the collector and the emitter of the IGBT tube are two switch ends.

Preferably, the voltage control switch is a TRIAC tube, and the main electrode T1 and the main electrode T2 of the TRIAC tube are two switch ends.

Preferably, the voltage control switch is a reverse series connection of two IGBT tubes, and the two collectors after the reverse connection of the two IGBT tubes are two switch ends.

Preferably, the voltage controlled switch is in reverse series connection of two MOSFET tubes, and the two drains after the reverse connection of the two MOSFET tubes are two switch ends.

Preferably, the voltage control switch is a reverse series connection of two TRIAC tubes, and the two main electrodes T2 after the reverse connection of the two TRIAC tubes are two switch ends.

Preferably, the method further comprises:

a first capacitor; the first capacitor and the MOSFET tube form a first half-control capacitor;

One end of the first capacitor is connected to a source of the MOSFET, and the other end of the first capacitor is connected to one end of the resonant capacitor not connected to the resonant coil, and a drain of the MOSFET is A resonant coil and a connection point of the resonant capacitor are connected.

Preferably, the method further comprises:

a second capacitor; the second capacitor and the IGBT tube form a second half-control capacitor;

One end of the second capacitor is connected to the emitter of the IGBT tube, and the other end of the second capacitor is connected to one end of the resonant capacitor not connected to the resonant coil, and the collector of the IGBT tube is A resonant coil and a connection point of the resonant capacitor are connected.

A limiter control device, comprising the above-mentioned limiter control circuit, further comprising:

a first driving voltage supply circuit;

The first driving voltage supply circuit is configured to supply a voltage to the first half control capacitor;

The first driving voltage supply circuit includes:

Rectifier, filter capacitor, isolated switching power supply, voltage sampling circuit, comparator and driver amplifier;

The resonant coil is not connected to one end of the connection point, the rectifier, the filter capacitor, the voltage sampling circuit, the comparator, the driving amplifier and the first half-control capacitor are sequentially connected, the isolation A switching power supply is connected in parallel across the filter capacitor.

a second driving voltage supply circuit;

The second driving voltage supply circuit is configured to supply a voltage to the second half control capacitor;

The second driving voltage supply circuit includes:

The resonant coil is not connected to one end of the connection point, the rectifier, the filter capacitor, the voltage sampling circuit, the comparator, the driving amplifier, and the second half-control capacitor are sequentially connected, and the isolation A switching power supply is connected in parallel across the filter capacitor.

A limiting control method is applied to the above-mentioned limiting control circuit, and the limiting control method includes:

The voltage control switch is controlled to be turned on when it is required to provide a stable voltage.

Preferably, the controlling the voltage control switch to be turned on includes:

The voltage control switch is controlled to be turned on by inputting a high level and a low level.

The voltage control switch is controlled to be turned on by pulse width modulation.

The invention provides a limiting control circuit, device and method, the circuit comprising: a resonant coil, a resonant capacitor and a voltage controlled switch; the resonant coil and the resonant capacitor are connected in series; two switches of the voltage controlled switch The terminals are respectively connected to the two end points of the resonant capacitor. When it is desired to provide a stable voltage, the voltage-controlled switch is controlled to be turned on, and the resonant capacitor is short-circuited. The resonant state of the original circuit is destroyed, which can provide a stable voltage or current, and solves the problem that the driven resonant ring is unstable.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a circuit diagram of a limiter control circuit according to Embodiment 1 of the present invention;

2 is a circuit diagram of a limiter control circuit according to Embodiment 2 of the present invention;

3a is a schematic structural view of a three-terminal voltage control switch provided by the present invention;

FIG. 3b is a schematic structural diagram of a three-terminal voltage control switch according to the present invention; FIG.

3c is a schematic structural view of another three-terminal voltage control switch provided by the present invention;

3d is a schematic structural view of a third three-terminal voltage control switch provided by the present invention;

4a is a schematic structural view of a four-terminal voltage control switch provided by the present invention;

4b is a schematic structural view of a four-terminal voltage control switch according to the present invention;

4c is a schematic structural view of another four-terminal voltage control switch provided by the present invention;

4d is a schematic structural view of a third four-terminal voltage control switch provided by the present invention;

5 is a circuit diagram of a limiter control circuit according to Embodiment 3 of the present invention;

6 is a circuit diagram of a limiter control circuit according to Embodiment 4 of the present invention;

Figure 7 is a circuit diagram of a limiter control device provided by the present invention;

8 is a schematic structural diagram of a limiter control circuit according to Embodiment 5 of the present invention;

9 is a schematic structural diagram of a limiter control circuit according to Embodiment 6 of the present invention;

10 is a schematic structural diagram of a limiter control circuit according to Embodiment 7 of the present invention;

11 is a schematic structural diagram of a limiter control circuit according to Embodiment 8 of the present invention;

12 is a schematic structural diagram of a limiter control circuit according to Embodiment 9 of the present invention;

FIG. 13 is a schematic structural diagram of a limiter control circuit according to Embodiment 10 of the present invention.

detailed description

The technical solution in the embodiment of the present invention will be further described below with reference to the accompanying drawings in the embodiments of the present invention. The invention is described in a clear and complete manner, and it is obvious that the described embodiments are only a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Embodiments of the present invention provide a limiting control circuit, including:

Resonant coil, resonant capacitor and voltage controlled switch;

The resonant coil and the resonant capacitor are connected in series; the two switch terminals of the voltage controlled switch are respectively connected to the two end points of the resonant capacitor.

Referring to Figures 1 and 2, Figures 1 and 2 illustrate the connection relationship of the components of the limiter control circuit.

In Fig. 1, L1 represents a resonant coil, C1 represents a resonant capacitor, voltage-controlled switch S1 is a three-terminal voltage-controlled switch, and an arrow represents a magnetic field. The resonant coil L1 and the resonant capacitor C1 are connected in series to form a driven resonant ring, and the two switching ends of the voltage controlled switch S1 are respectively connected to the two end points of the resonant capacitor C1.

The limiter control circuit has three output terminals: A, B, C, where C is the common end of the slave resonant ring; the circuit has two output combinations: AB or AC, and the AB output is from both ends of the series driven ring. The output is output from the non-common terminal; the AC output is output from both ends of the resonant coil L1, and the output terminal includes a common terminal C.

In Fig. 2, L1 represents a resonant coil, C1 represents a resonant capacitor, voltage-controlled switch S1 is a four-terminal voltage-controlled switch, and an arrow represents a magnetic field. The resonant coil L1 and the resonant capacitor C1 are connected in series to form a driven resonant ring, and the two switching ends of the voltage controlled switch S1 are respectively connected to the two end points of the resonant capacitor C1.

The limiter control circuit has three outputs: A, B, and C, where C is the common end of the slave resonant ring. The circuit has two output combinations: AB or AC. The AB output is output from both ends of the driven resonant ring, that is, from the non-common terminal. The AC output is output from both ends of the resonant coil L1, and the output terminal includes a common terminal C. .

The working process is: when the voltage control switch S1 is turned on, the resonant capacitor C1 is short-circuited, and the resonant state of the driven resonant ring is destroyed, the amplitude of the resonant ring is controlled within a certain range, and a stable voltage or current can be output. . When the voltage control switch S1 is turned off, the resonant capacitor C1 is not short-circuited and does not destroy the resonance state.

The limiter control circuit provided by the invention controls the voltage control switch to be turned on when the stable voltage needs to be supplied, and the resonant capacitor is short-circuited. The resonance state of the original circuit is destroyed and can provide stable The voltage or current solves the problem of unstable operation of the driven resonant ring.

Optionally, in another embodiment of the present invention, the voltage control switch may select different voltage control switches according to specific conditions. The voltage control switch can be an IGBT tube, the collector and the emitter of the IGBT tube are two switch ends; the voltage control switch can be a MOSFET tube, the drain and source of the MOSFET tube are two switch ends; the voltage control switch can be a TRIAC tube, The main electrode T1 and the main electrode T2 of the TRIAC tube are two switch ends; the voltage control switch can be reversely connected in series for two IGBT tubes, and the two collectors after the reverse connection of the two IGBT tubes are two switch ends; The switch can be reversely connected in series for two MOSFET tubes. The two drains of the two MOSFET tubes in reverse series are two switch terminals; the voltage control switch can be reverse series connected for two TRIAC tubes, and the two TRIAC tubes are connected in series after reverse connection. The two main electrodes T2 are two switch terminals.

Among them, an IGBT (Insulated Gate Bipolar Transistor) and an insulated gate bipolar transistor are composite full-voltage-driven power semiconductor devices composed of a BJT (bipolar transistor) and a MOS (insulated gate field effect transistor). MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), a metal-oxide semiconductor field effect transistor, is a field effect transistor that can be widely used in analog circuits and digital circuits. The triac TRIAC tube is essentially a bidirectional thyristor. It is developed on the basis of a common thyristor. It can replace not only two thyristors connected in parallel with reverse polarity, but also a single trigger circuit.

It should be noted that the collector of the IGBT tube is also referred to as a drain, the emitter of the IGBT tube is also referred to as a source, and the gate of the IGBT tube is also referred to as a gate.

In order to enable those skilled in the art to more clearly understand the voltage control switch of the present invention, please refer to FIG. 1, FIG. 2, FIG. 3a, FIG. 3b, FIG. 3c, FIG. 3d, FIG. 4a, FIG. 4b, FIG. 4d. Among them, the voltage control switch in Fig. 3a is a three-terminal voltage control switch, and the voltage control switch in Fig. 4a is a four-terminal voltage control switch.

In Fig. 3a, the voltage control switch S1 has three ends of 1, 2, and 3, wherein the two ends are the two switch ends, and the one end is the control end. The IGBT tube in Figure 3b has three poles, namely collector C, emitter E and gate G. The MOSFET of Figure 3c also has three poles, namely drain D, gate G and source S. The three poles of the TRIAC tube in Figure 3d are the main electrode T1, the main electrode T2 and the gate G, respectively.

When the voltage control switch S1 is an IGBT tube, the corresponding relationship of the pin position is: 1-G, 2-C, 3-E; when the voltage control switch S1 is a MOSFET tube, the corresponding relationship of the pin position is: 1-G, 2- D, 3-S; when the voltage control switch When S1 is a TRIAC tube, the corresponding relationship of the feet is: 1-G, 2-T2, 3-T1.

In Fig. 4a, the voltage control switch S1 has four ends of 1, 2, 3 and 4, wherein 2 and 3 are two switch terminals, and 1, 4 are two control terminals, wherein 4 terminals are used for grounding. The voltage-controlled switch S1 has two IGBT tubes in reverse series or two MOSFET tubes in reverse series or two TRIAC tubes in reverse series.

Specifically, when the voltage control switch S1 is in reverse series connection of two IGBT tubes, referring to FIG. 4b, the corresponding relationship of the pins is: 1-G, 2-C, 3-C, 4-E, when the voltage control switch S1 is When the two MOSFET tubes are connected in series in reverse, referring to FIG. 4c, the corresponding positions of the pins are: 1-G, 2-D, 3-D, 4-S. When the voltage control switch S1 is in reverse series connection of two TRIAC tubes, Referring to FIG. 4d, the correspondence between the feet is: 1-G, 2-T2, 3-T2, 4-T1.

It should be noted that, whether it is a three-terminal voltage control switch or a four-terminal voltage control switch, the control terminal 1 is used to control the on/off of the voltage control switch.

In this embodiment, the voltage control switch S1 is an IGBT tube or a MOSFET tube or a TRIAC tube, or the voltage control switch is two IGBT tubes in reverse series or two MOSFET tubes in reverse series or two TRIAC tubes in reverse series. There are many ways to choose, and you can choose according to different situations.

Optionally, in another embodiment of the present invention, when the voltage control switch S1 is a MOSFET, the limiting control circuit further includes:

One end of the first capacitor is connected to the source of the MOSFET, the other end of the first capacitor is connected to one end of the resonant capacitor to which the resonant coil is not connected, and the drain of the MOSFET is connected to the connection point of the resonant coil and the resonant capacitor.

When the voltage control switch S1 is an IGBT tube, the limiting control circuit further includes: a second capacitor; the second capacitor and the IGBT tube form a second half control capacitor;

One end of the second capacitor is connected to the emitter of the IGBT tube, and the other end of the second capacitor is connected to one end of the resonant capacitor to which the resonant coil is not connected, and the collector of the IGBT tube is connected to the connection point of the resonant coil and the resonant capacitor.

Optionally, in another embodiment of the present invention, when the voltage control switch S1 is a MOSFET, a limiting control device is provided. In addition to the limiting control circuit including the MOSFET, the method further includes:

a first driving voltage supply circuit;

a first driving voltage supply circuit for supplying a voltage to the first half control capacitor;

The first driving voltage supply circuit includes:

One end of the non-connecting point of the resonant coil, the rectifier, the filter capacitor, the voltage sampling circuit, the comparator, the driving amplifier and the first half-control capacitor are sequentially connected, and the isolating switching power supply is connected in parallel at both ends of the filter capacitor.

Optionally, in another embodiment of the present invention, when the voltage control switch S1 is an IGBT tube, a limiting control device is provided. In addition to the limiting control circuit including the IGBT tube, the method further includes:

a second driving voltage supply circuit;

a second driving voltage supply circuit for supplying a voltage to the second half control capacitor;

The second driving voltage supply circuit includes:

One end of the non-connecting point of the resonant coil, the rectifier, the filter capacitor, the voltage sampling circuit, the comparator, the driving amplifier and the second half-control capacitor are sequentially connected, and the isolating switching power supply is connected in parallel at both ends of the filter capacitor.

It should be noted that when the voltage control switch S1 is an IGBT tube or a MOSFET tube, the voltage control switch may also be referred to as a switch tube.

Referring now to Figures 5, 6, and 7, a circuit diagram and a limiter control device for a limiter control circuit when the voltage control switch is a MOSFET or an IGBT tube will be described.

Referring to FIG. 5, FIG. 5 shows a case where the resonant coil and the resonant capacitor are connected in series, and the switching transistor is a MOSFET.

Wherein, L1 is a resonant coil, C1 is a resonant capacitor, L1 and C1 are connected in series to form a driven resonant ring, and the first capacitor C2 is connected in series with the MOSFET 101 to form a first half-controlled capacitor, and the first half-controlled capacitor is connected in parallel with the resonant capacitor C1. At the same time, it is connected in series with the resonant coil L1, A and B are output terminals, and arrows indicate magnetic fields. When the gate of the MOSFET 101 is at a high level, the MOSFET 101 is turned on, since the internal resistance of the MOSFET 101 is small, close to 0, at this time, the capacitor C2 is connected in parallel with the resonant capacitor C1, and the driven resonant ring is optimal. The resonance state is destroyed, the amplitude is reduced or even completely stopped; when the gate When it is low, the MOSFET 101 is turned off, and since the MOSFET 101 is open, the capacitor C2 is inactive.

Referring to Fig. 6, Fig. 6 shows a case where the resonant coil and the resonant capacitor are connected in series, and the voltage controlled switch is an IGBT tube.

Wherein, L1 is a resonant coil, C1 is a resonant capacitor, L1 and C1 are connected in series to form a driven resonant ring, and a second capacitor C3 is connected in series with the IGBT tube 102 to form a second half-controlled capacitor, and the second half-controlled capacitor is connected in parallel with the resonant capacitor C1. In series with the resonant coil L1, A and B are output terminals, and arrows indicate magnetic fields. The specific working process is the same as that of FIG. 1 and will not be described here.

The circuit diagram of the limiter control device is shown in Fig. 7. Specifically, the resonant capacitor C1 and the resonant coil L1 are connected in series to form a driven resonant ring, 103 is a rectifier, C4 is a filter capacitor, 104 is an isolated switching power supply, resistors R1 and R2 are connected in series to form a voltage sampling circuit, 105 is a comparator, 106 is The driver amplifier, capacitor C2 and MOSFET 101 form the first half-control capacitor, Vd represents the output voltage, Vreg is the reference voltage, R3 is the current limiting resistor, and R4 is the discharge resistor.

The circuit diagram of the driven resonant ring and the first half-controlled capacitor has been described in the above embodiments. Please refer to the above embodiment, and details are not described herein again. Both MOSFET and IGBT transistors are voltage-controlled devices that require a suitable drive voltage for their gates to function properly. The working process of each module in Figure 7 is:

The output end of the driven resonant ring is filtered by the rectifier 103 and filtered by the filter capacitor C4 to obtain a high voltage direct current. The isolated switching power supply 104 is input to a switching power supply, and the high voltage direct current is voltage-converted to obtain the DC voltage required for the gate of the MOSFET. Generally, between 10V and 18V, the DC high voltage is subjected to voltage sampling by a voltage sampling circuit composed of R1 and R2, and then sent to the comparator 105 for voltage comparison. If the detected voltage exceeds the set voltage, the comparator 105 outputs a high level. The high level is then amplified by the driver amplifier 106, and then sent to the gate of the MOSFET through the resistor R3. At this time, the MOSFET is turned on, the first half control capacitor is effective, and the complete resonance of the slave resonant ring is destroyed. Can provide a stable voltage or current.

Among them, the current limiting resistor R3 and the discharging resistor R4 protect the MOSFET.

It should be noted that, in FIG. 5, FIG. 6 and FIG. 7, the first half-control capacitor is composed of the first capacitor and the MOSFET tube, and the second half-control capacitor is composed of the second capacitor and the IGBT tube, and the MOSFET tube and the IGBT tube are in operation. One end must be connected to "ground", which is the lowest potential reference point of a circuit, not the real ground. The choice of "ground" is to facilitate the effective operation of the MOSFET and IGBT tubes. In the series of driven resonant rings, there is only one resonant coil L1 and resonant capacitor C1. At the public midpoint, select this midpoint as the "ground".

The limiting control circuit provided in this embodiment controls the MOSFET tube or the IGBT tube to be turned on when a stable voltage or current is required to be supplied, thereby controlling the conduction of the first half-controlled capacitor or the second half-controlled capacitor, the resonant coil and the resonant capacitor. The resonant state is destroyed, and a stable voltage or current can be provided, which solves the problem that the driven resonant ring is unstable. In addition, by setting the driving voltage supply circuit, the first half-control capacitor or the second half-control capacitor can be supplied with a suitable voltage, and the driven resonant ring can be controlled by the first half-controlled capacitor or the second half-controlled capacitor being turned on and off. The state of resonance.

In another embodiment of the present invention, a limiting control method is provided, which is applied to the above-mentioned limiting control circuit, and the limiting control method includes:

When the stable voltage needs to be supplied, the control voltage control switch is turned on.

Specifically, the control voltage control switch is turned on, and specifically includes: controlling the voltage control switch to be turned on by adopting an input high and low level mode or a pulse width modulation manner.

It should be noted that when the control terminal 1 inputs a high level, the two switch terminals are turned on, the on-resistance is zero or close to zero, the resonant capacitor is short-circuited, the original resonance state is changed, and the amplitude is decreased. When the control terminal 1 is low level, the two switch terminals are short-circuited, and the open circuit resistance is infinite. The resonant capacitor is effective, restores the original resonant state, and the amplitude rises.

In order to understand the solution more clearly by those skilled in the art, the working principle of the limiter control circuit will now be described. Reference is made to Figures 8, 9, 10, 11, 12 and 13.

In Fig. 8, L1 denotes a resonance coil, C1 denotes a resonance capacitor, and resonance coil L1 and resonance capacitor C1 constitute a driven resonance ring. S1 represents the voltage control switch. At this time, the voltage control switch S1 is a three-terminal voltage control switch, 103 represents a rectifier, which is used to convert alternating current into direct current, C4 is a filter capacitor, and 107 represents a direct current DC2DC power supply or a switching power supply SMPS, which is used for voltage The control switch S1 provides a driving voltage, the resistors R1 and R2 constitute a voltage sampling circuit, and 108 represents a voltage comparator or a pulse width modulation PWM generator for providing a high-low level or PWM signal for the voltage-controlled switch S1, and Q1 and Q2 constitute a driving amplifier. 106, R3 is a current limiting resistor, R4 is a discharging resistor, and Vd is an output voltage.

In this embodiment, the AB output terminal is used. In the alternating magnetic field, the AB output terminal outputs alternating current, which is rectified by the rectifier 103 and filtered by the filter capacitor C4 to obtain a DC voltage. When the DC voltage reaches a certain value, at this time, if the voltage is 108, the voltage is 108. The comparator, the voltage comparator 108 outputs a high level, is amplified by the driver amplifier 106, and is output to the control terminal of the voltage control switch S1, at which time the voltage control is turned on. When S1 is turned on, the resonant capacitor C1 is short-circuited, the original resonant state is changed, the amplitude of the two ends of AB decreases, and the voltage across the smoothing capacitor C4 also decreases. When falling to a specified value, the voltage comparator 108 is inverted, and the output is inverted. Low level, the voltage control switch S1 is turned off, the original resonance state is restored, and the cycle is performed to maintain the voltage on the filter capacitor C4 at a specified value.

When 108 is a PWM generator, the duty ratio of the PWM signal is proportional to the voltage at the input terminal. As the voltage on the filter capacitor C4 rises, the duty ratio of the PWM signal increases, and the on-time of the voltage-controlled switch S1. Increasing, the time of the deceleration of the slave resonant ring is prolonged, and the voltage on the filter capacitor C4 is decreased. As the voltage of the filter capacitor C4 decreases, the duty ratio of the PWM signal output by the PWM generator 108 decreases, and the slave resonant ring stops vibrating. The time is shortened, the voltage on the filter capacitor C4 rises, and the cycle is such that the voltage on C4 is maintained at the specified value.

In Fig. 9, the resistors R1, R2 and R5 constitute a voltage sampling circuit, and the voltage control switch S1 is a four-terminal voltage control switch. In Fig. 10, the rectifier 103 employs full-wave rectification. In Figure 11, the rectifier 103 is full-wave rectified, and the voltage-controlled switch S1 is a four-terminal voltage-controlled switch. In Figure 12, the output is the A-C output and the rectifier 103 is full-wave rectified. In Fig. 13, the rectifier 103 is full-wave rectified, and the voltage control switch S1 is a four-terminal voltage control switch. For the working process of the remaining components and the respective components, please refer to the description in FIG. 8 , and details are not described herein again. It should be noted that the circuit diagrams of FIG. 8 to FIG. 13 are slightly different, but the working principles can be referred to each other.

It should be noted that the "ground" is set for the effective operation of the voltage control switch S1, that is, the three ends of the three-terminal voltage control switch are grounded, and the four ends of the four-terminal voltage control switch are grounded, one end is grounded The voltages are: 10-18VDC for the IGBT tube, 5-10VDC for the MOSFET, and 1-5VDC for the TRIAC tube. In order to be able to achieve the above voltage, in Figures 8 to 13, the places where the ground terminal symbols are drawn are grounded.

It should be noted that the foregoing embodiments are written in a progressive relationship, and the foregoing embodiments may be referred to each other.

The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the broadest of the principles and novel features disclosed herein. range.

Claims

A limiter control circuit, comprising:

Resonant coil, resonant capacitor and voltage controlled switch;

The resonant coil and the resonant capacitor are connected in series; two switch ends of the voltage controlled switch are respectively connected to two end points of the resonant capacitor.
The limiter control circuit of claim 1 wherein said voltage controlled switch is a MOSFET transistor, said drain and source of said MOSFET being substantially two switch terminals.
The limiter control circuit according to claim 1, wherein the voltage control switch is an IGBT tube, and the collector and the emitter of the IGBT tube are two switch terminals.
The limiter control circuit according to claim 1, wherein the voltage control switch is a TRIAC tube, and the main electrode T1 and the main electrode T2 of the TRIAC tube are two switch terminals.
The limiter control circuit according to claim 1, wherein the voltage control switch is a reverse series connection of two IGBT tubes, and the two collectors after the reverse connection of the two IGBT tubes are two switch ends. .
The limiter control circuit according to claim 1, wherein the voltage-controlled switch has two MOSFET tubes connected in reverse series, and the two drains after the reverse connection of the two MOSFET tubes are two switch terminals.
The limiter control circuit according to claim 1, wherein the voltage control switch has two TRIAC tubes connected in reverse series, and the two main electrodes T2 after the two TRIAC tubes are connected in series are two switches. end.
The limiter control circuit of claim 2, further comprising:

a first capacitor; the first capacitor and the MOSFET tube form a first half-control capacitor;

One end of the first capacitor is connected to a source of the MOSFET, and the other end of the first capacitor is connected to one end of the resonant capacitor not connected to the resonant coil, and a drain of the MOSFET is A resonant coil and a connection point of the resonant capacitor are connected.
The limiter control circuit of claim 3, further comprising:

a second capacitor; the second capacitor and the IGBT tube form a second half-control capacitor;

One end of the second capacitor is connected to an emitter of the IGBT tube, and the second capacitor The other end is connected to one end of the resonant capacitor to which the resonant coil is not connected, and the collector of the IGBT transistor is connected to a connection point of the resonant coil and the resonant capacitor.
A limiter control device, comprising the limiter control circuit of claim 8, further comprising:

a first driving voltage supply circuit;

The first driving voltage supply circuit is configured to supply a voltage to the first half control capacitor;

The first driving voltage supply circuit includes:

Rectifier, filter capacitor, isolated switching power supply, voltage sampling circuit, comparator and driver amplifier;

The resonant coil is not connected to one end of the connection point, the rectifier, the filter capacitor, the voltage sampling circuit, the comparator, the driving amplifier and the first half-control capacitor are sequentially connected, the isolation A switching power supply is connected in parallel across the filter capacitor.
A limiter control device, comprising the limiter control circuit of claim 9, further comprising:

a second driving voltage supply circuit;

The second driving voltage supply circuit is configured to supply a voltage to the second half control capacitor;

The second driving voltage supply circuit includes:

Rectifier, filter capacitor, isolated switching power supply, voltage sampling circuit, comparator and driver amplifier;

The resonant coil is not connected to one end of the connection point, the rectifier, the filter capacitor, the voltage sampling circuit, the comparator, the driving amplifier, and the second half-control capacitor are sequentially connected, and the isolation A switching power supply is connected in parallel across the filter capacitor.
A limiting control method, which is applied to the limiting control circuit according to any one of claims 1 to 9, wherein the limiting control method comprises:

The voltage control switch is controlled to be turned on when it is required to provide a stable voltage.
The limiting control method according to claim 12, wherein the controlling the voltage control switch to be turned on comprises:

The voltage control switch is controlled to be turned on by inputting a high level and a low level.
The limiter control method according to claim 12, wherein said control station The voltage control switch is turned on, and specifically includes:

The voltage control switch is controlled to be turned on by pulse width modulation.