CN216625578U

CN216625578U - Medical microwave magnetron high-voltage driving circuit

Info

Publication number: CN216625578U
Application number: CN202123174291.0U
Authority: CN
Inventors: 张豪; 杜振磊; 梁帅帅; 李飞; 李高亚; 王世兵; 孙良俊
Original assignee: Nanjing Eco Microwave System Co ltd
Current assignee: Nanjing Yigao Medical Technology Co ltd
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2022-05-27
Anticipated expiration: 2031-12-17

Abstract

The utility model relates to a medical microwave magnetron high-voltage driving circuit, belonging to the technical field of medical instruments. The high-voltage driving circuit comprises a driving transformer, a half-bridge converter, a boosting transformer, a voltage-multiplying rectifying circuit and a sampling module. The novel holistic circuit scheme of this implementation for match the medical microwave magnetron of drive, satisfy its high voltage, undercurrent, miniwatt's demand, improve the efficiency of circuit, further improved the efficiency of magnetron.

Description

Medical microwave magnetron high-voltage driving circuit

Technical Field

The utility model relates to the technical field of medical instruments, in particular to a medical microwave magnetron high-voltage driving circuit.

Background

Magnetrons are important components of medical microwave therapy or physiotherapy equipment, and can convert electric energy in the form of direct current or pulsed high voltage into microwave energy. The work efficiency and stability are two of the most important issues in magnetron applications, and the achievement of the highest efficiency and the best stability is the goal of researchers in various fields, and the magnetron can work stably in a wide range of working voltages, and the total efficiency of the magnetron depends on the product of the electron efficiency and the circuit efficiencyη=η _e η _cFig. 1 is a diagram showing the relationship between the total efficiency of the magnetron and the electron efficiency and the circuit efficiency, and an optimal impedance can be found from the diagram, so that the total efficiency of the magnetron reaches the maximum. The electronic efficiency has been determined in the purchase customization process, and in actual use, the overall efficiency of the magnetron can only be improved by designing a high-efficiency circuit with the best match.

Fig. 2 is a schematic diagram of a high-voltage driving circuit of a conventional magnetron, the circuit is composed of a transformer T1, four rectifying high-voltage diodes D1, D2, D3, D4 and a capacitor, and the circuit has large heat generation due to large distributed capacitance of the transformer in the using process, so that the circuit loss is increased, the efficiency of the circuit is reduced, the efficiency of the magnetron is reduced, and the performance of the transformer is reduced due to overhigh temperature and even the transformer is damaged.

The magnetron can be divided into two types of pulse magnetron and continuous wave magnetron due to different working states, the continuous wave magnetron with the power of less than 300W is mainly used for medical microwave treatment and physical therapy, and in order to flexibly meet the practical application requirements of the magnetron, an optimized circuit needs to be improved, and the circuit efficiency is improved.

Disclosure of Invention

The utility model aims to provide a medical microwave magnetron high-voltage driving circuit which is used for matching and driving a medical microwave magnetron and meeting the requirements of high voltage, low current and low power of the medical microwave magnetron.

In order to achieve the above purpose, according to the technical scheme provided by the utility model, the medical microwave magnetron high-voltage driving circuit comprises a driving transformer, a half-bridge converter, a boosting transformer, a voltage doubling rectifying circuit and a sampling module, wherein the circuit modules are sequentially connected.

The driving transformer adopts a transformer T2 with double secondary windings, has equal amplitude and adjustable pulse width, and drives the bases of Q2 and Q3 by pulse signals with the phase difference of 180 degrees;

the half-bridge converter comprises a bridge consisting of Q2 and Q3 driven by two secondary coils of a transformer T2 respectively, a basic topological circuit diagram of the half-bridge converter is formed by connecting a diagonal line of the bridge with a primary coil of the transformer T4, and two groups of C30/R23 and C31/R25 in the circuit are used for absorbing switching pulse spikes of Q2 and Q3;

the primary winding of the step-up transformer T4 adopts a 1-slot high-voltage winding, the secondary winding adopts a 4-slot high-voltage winding, the primary coil is connected with the end of the half-bridge converter, and the secondary coil is connected with the input end of the voltage-doubling rectifying circuit;

the voltage doubling rectifying circuit adopts a voltage doubling rectifying circuit, so that the winding of a secondary coil of the transformer T4 is reduced by half;

the sampling module comprises voltage protection sampling of a mutual inductor T3, current sampling regulation output power of a sampling resistor R27 and a high-voltage protection sampling resistor R28.

Compared with the prior art, the utility model has the following beneficial effects:

1. the circuit of the utility model adopts the same reverse double secondary coil driving transformer, amplifies the small pulse signal sent by the singlechip, alternately inputs the small pulse signal into the half-bridge converter to form an alternating current signal with higher quality, lays a foundation for the secondary boosting and voltage-multiplying rectification of the back-end circuit, and has simple structure and high cost performance of the power supply topology circuit.

2. The circuit of the utility model adopts the transformer T4 wound by secondary sub-slots and is matched with the voltage doubling rectifying circuit of the secondary of the transformer T4, so that the winding of the secondary coil of the T4 is reduced by half, and simultaneously, the voltage doubling rectifying circuit is adopted, so that the design of the common full-bridge rectifying circuit is simplified, the using amount of diodes is reduced by half, the capacitors with low cost are used for replacing, and the circuit cost is reduced.

3. The circuit of the utility model adopts the transformer T4 wound by secondary sub-slots, and the design scheme ensures that the distributed capacitance of the transformer is reduced, the loss is reduced and the efficiency of the transformer is improved.

4. This novel circuit of implementation adopts three sampling module for in time detect circuit output state, the output is too high or cross low timely regulation, and protection circuit can not destroy because of exporting too high, crosses low not satisfying the output demand, thereby ensures that circuit output is stable, has further ensured the stability of magnetron.

5. The novel integrated circuit scheme is designed for matching and driving the medical microwave magnetron, meets the requirements of high voltage, low current and low power, improves the efficiency of the circuit, and further improves the efficiency of the magnetron.

Drawings

FIG. 1 is a graph illustrating the efficiency curve of a magnetron.

Fig. 2 is a schematic diagram of a conventional magnetron high voltage driving circuit.

FIG. 3 is a high voltage circuit diagram of the present invention.

Fig. 4 is a circuit flow diagram of a half-bridge converter of the present invention.

Fig. 5 is a schematic diagram of the transformer T4 of the present invention.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 3, the medical microwave magnetron high-voltage driving circuit includes a driving transformer T2, a half-bridge converter 1, a step-up transformer T4, a voltage-doubling rectifying circuit 2, a transformer T3 of a sampling module, a sampling resistor R27, and a sampling resistor R28.

the half-bridge converter 1 comprises a bridge formed by Q2 and Q3 driven by two secondary coils of a transformer T2 respectively, a basic topological circuit diagram of the half-bridge converter is formed by connecting a diagonal line of the bridge with a primary coil of the transformer T4, and two groups of C30/R23 and C31/R25 in the circuit are used for absorbing switching pulse spikes of Q2 and Q3; the half-bridge converter 1 forms isolation protection with a high-voltage circuit part through the transformer T2, the transformer T3 and the transformer T4, prevents the mutual interference of a 220V circuit part and a boosted circuit, and prevents the circuit from generating harm to operators in debugging and using processes.

Sending a PWM signal from a special chip to a driving transformer T2 through CN4, acting on a primary side of a transformer T2, inducing two complementary driving signals at a secondary side, when the current of a coil of the transformer N1 flows from a 7 end to a 6 end, a voltage signal is mutually induced by the coil of a secondary N2 of the transformer T2, the coil 1 end of the N2 is positive voltage, the coil 2 end of the N2 is negative voltage, the coil of the secondary N3 of the transformer T2 is mutually induced by a voltage signal, the coil 5 end of the N3 is positive voltage, the coil 4 end of the N3 is negative voltage, at the moment, Q2 is turned off, Q3 is turned on, and the current sequentially passes through C32, T4, T3 and Q3 to form a loop to PGND; when the coil current of the transformer N1 flows from the 6 terminal to the 7 terminal, Q2 is turned on, Q3 is turned off, and the current is looped to PGND through Q2, T3, T4 and C33 in sequence, so that a required alternating voltage signal can be obtained at the coil N1 of the transformer T4, and the circuit flow diagram of the half-bridge converter is shown in FIG. 4.

The primary winding of the step-up transformer T4 adopts a 1-slot high-voltage winding, the secondary winding adopts a 4-slot high-voltage winding, the primary coil is connected with the end of the half-bridge converter, the secondary coil is connected with the input end of the voltage-doubling rectifying circuit, and the schematic diagram and the framework winding of the transformer T4 are shown in FIG. 5;

the voltage doubling rectifying circuit adopts a voltage doubling rectifying circuit, so that the secondary coil winding of the transformer T4 is reduced by half;

the sampling module comprises voltage protection sampling of a transformer T3, current sampling regulation output power of a sampling resistor R27 and a high-voltage protection sampling resistor R28.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention. The protection scope of the patent of the utility model is subject to the appended claims.

Claims

1. A medical microwave magnetron high-voltage driving circuit is characterized in that: the device comprises a driving transformer, a half-bridge converter, a boosting transformer, a voltage-doubling rectifying circuit and a sampling module; the driving transformer with double secondary windings is used to amplify the small pulse signal from the single-chip microcomputer, and the small pulse signal is alternately input to the half-bridge converter to form AC signal with high quality, and input to the step-up transformer with secondary winding and the voltage doubling rectifying circuit with double voltage doubling.

2. The medical microwave magnetron high-voltage driving circuit according to claim 1, characterized in that: the driving transformer adopts a transformer T2 with double secondary windings, and has bases for driving Q2 and Q3 by pulse signals with equal amplitude, adjustable pulse width and 180-degree phase difference.

3. The medical microwave magnetron high-voltage driving circuit according to claim 1, characterized in that: the half-bridge converter comprises a bridge formed by Q2 and Q3 driven by two secondary coils of a transformer T2 respectively, a basic topological circuit diagram of the half-bridge converter is formed by connecting a diagonal line of the bridge with a primary coil of the transformer T4, and two groups of C30/R23 and C31/R25 in the circuit are used for absorbing switching pulse spikes of Q2 and Q3.

4. The medical microwave magnetron high-voltage driving circuit according to claim 1, characterized in that: the primary winding of the step-up transformer T4 adopts a 1-slot high-voltage winding, the secondary winding adopts a 4-slot high-voltage winding, the primary coil is connected with the end of the half-bridge converter, and the secondary coil is connected with the input end of the voltage-doubling rectifying circuit.

5. The medical microwave magnetron high-voltage driving circuit according to claim 1, characterized in that: the voltage-doubling rectifying circuit adopts a voltage-doubling rectifying circuit, so that the winding of a secondary coil of the transformer T4 is reduced by half.

6. The medical microwave magnetron high-voltage driving circuit according to claim 1, characterized in that: the sampling module comprises voltage protection sampling of a transformer T3, current sampling regulation output power of a sampling resistor R27 and a high-voltage protection sampling resistor R28.