CN102724777A

CN102724777A - Resonant circuit of electromagnetic oven

Info

Publication number: CN102724777A
Application number: CN2012101639297A
Authority: CN
Inventors: 丁娟; 陈殊; 陈伟; 洪尧枝
Original assignee: Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Current assignee: Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Priority date: 2012-05-24
Filing date: 2012-05-24
Publication date: 2012-10-10

Abstract

The invention provides a resonant circuit of an electromagnetic oven. The resonant circuit comprises a rectification filter circuit (2), a resonant circuit (5) and a power tube (3), wherein the input end of the rectification filter circuit (2) is connected with the mains power supply; one end of the resonant circuit (5) is connected with the output end of the rectification filter circuit (2); the other end of the resonant circuit (5) is connected with the power tube (3); the resonant circuit is characterized in that the resonant circuit (5) comprises an induction coil L1 and resonant capacitors C1, C2 and C3; the induction coil L1 and the resonant capacitor C2 form a parallel circuit (4); one end of the parallel circuit (4) is connected in series with the capacitor C1; and the other end of the parallel circuit (4) is connected in series with the resonant circuit C3 which is connected in span with two ends of the C electrode and the E electrode of the power tube (3). By adopting a double back loop resonant circuit, the voltage of the C electrode of the power tube (3) is reduced effectively, thereby protecting switch components effectively.

Description

The resonant circuit of electromagnetic oven

Technical field

The present invention relates to the electromagnetic oven field, in particular for the resonant circuit of electromagnetic oven.

Background technology

Popularize along with what electromagnetic oven was used, its security reliability is had increasingly high requirement.Traditional electromagnetic oven; The scheme that its resonant circuit generally adopts inductance coil and independent resonant capacitance parallel connection to cooperate; (to call in the following text: C pole tension IGBT) is higher for the power tube of the electromagnetic oven that adopts this resonant circuit its switching device when work; The electric current that flows through IGBT is excessive, causes IGBT owing to overvoltage or overheated the damage easily.At present in order to solve this type of problem, most compressive resistances of improving IGBT etc. of adopting strengthen the methods of element design parameter, but fail fundamentally to solve the C pole tension of the IGBT when reducing resonance.

Summary of the invention

The objective of the invention is provides a kind of resonant circuit of electromagnetic oven for solving the prior art problem, can effectively reduce the C pole tension of power tube IGBT, has protected switching device, can make the switching device working stability reliable simultaneously, promotes efficient.

The present invention for the technical scheme that solution prior art problem provides is: the resonant circuit of electromagnetic oven; Comprise current rectifying and wave filtering circuit, resonant circuit, power tube; Said current rectifying and wave filtering circuit input connects civil power, and said resonant circuit one end connects the output of current rectifying and wave filtering circuit, and the other end connects power tube; Said resonant circuit comprises inductance coil L1 and resonant capacitance C1, C2 and C3; Inductance coil L1 and resonant capacitance C2 form parallel circuits, and an end of parallel circuits is connected with resonant capacitance C1, and the other end is connected with the resonant capacitance C3 of the C utmost point that is connected across power tube with E utmost point two ends.

Said resonant capacitance C1 both can pass through low frequency signal, also can pass through high-frequency signal.

Said low frequency signal is the power frequency component of 100Hz or 120Hz.

Said resonant capacitance C2 and/or C3 are can be through the electric capacity of high-frequency signal.

Said high-frequency signal is the above power frequency component of 20KHz.

The invention has the beneficial effects as follows: resonant circuit of the present invention adopts the dual loopback resonant circuit; When using the resonant capacitance of identical parameters; Equivalent capacitance value in the resonant circuit is greater than the capacitance of the single resonant tank of prior art; So electromagnetic oven is under the identical situation of power, can effectively reduce the C pole tension of power tube IGBT, thus protection switch device effectively; And the resonant tank of the present invention voltage that power tube IGBT opens when low-power is lower, can effectively reduce turn-on consumption, makes the switching device working stability reliable, promotes efficient.

Description of drawings

Fig. 1 is connected the principle schematic in the electromagnetic oven for the present invention.

Embodiment

Be described further below in conjunction with accompanying drawing and embodiment specific embodiments of the invention.

As shown in Figure 1; The present invention includes current rectifying and wave filtering circuit 2, resonant circuit 5, power tube 3 (IGBT), current rectifying and wave filtering circuit 2 inputs connect civil power, and said resonant circuit 5 one ends connect current rectifying and wave filtering circuit 2; The other end connects power tube 3; Said resonant circuit 5 comprises inductance coil L1 and resonant capacitance C1, C2 and C3, and resonant capacitance C3 is connected across the two ends of the C utmost point and the E utmost point of power tube 3, and inductance coil L1 and resonant capacitance C2 form parallel circuits 4; One end of parallel circuits 4 is connected with resonant capacitance C1, and the other end is connected with resonance C3.

Said resonant capacitance C1 both can also can pass through the above high-frequency signal of 20KHz through the low frequency signal of 100Hz or 120Hz.When power tube 3 is opened, after 2 rectifications of civil power (low frequency signal of 50Hz or 60Hz) process current rectifying and wave filtering circuit, obtain the low-frequency voltage of 100Hz or 120Hz, give resonant capacitance C1 charging; When power tube 3 turn-offed, resonant capacitance C1 and inductance coil L1 resonant capacitor C 3 formed resonant circuit, and the resonant circuit operating frequency is more than 20KHz, and resonant capacitance C1 is through the above high-frequency current of 20KHz.

Said resonant capacitance C2 and/or C3 are can be through the electric capacity of the above high-frequency signal of 20KHz.When power tube 3 turn-offs, parallelly connected formation first resonant tank of inductance coil L1 with resonant capacitance C2; Resonant capacitance C1 and inductance coil L1 resonant capacitor C 3 forms second resonant circuit, and the operating frequency of resonant circuit is all more than 20KHz, so resonant capacitance C2 and C3 are through the high-frequency current more than the 20KHz.

During electromagnetic oven work, this resonant circuit can form two resonant tanks, by parallelly connected first resonant tank that forms with resonant capacitance C2 of inductance coil L1; And second resonant tank that forms by inductance coil L1, resonant capacitance C3 resonant capacitor C 1.When power tube 3 turn-offed, resonant capacitance C1, C3 participated in resonance; When power tube 3 was opened, resonant capacitance C1, C3 strobed.Owing in the circuit two resonant circuits that formed by three electric capacity and inductance coil are arranged; When using the electric capacity of identical parameters; Equivalent capacitance value in the resonant circuit is greater than the capacitance of the single resonant tank of prior art; Thereby under the identical situation of electromagnetic oven power, can effectively reduce the C pole tension of power tube 3, thereby protected switching device effectively; And the resonant tank of this invention voltage that power tube 3 is opened when low-power is lower, can effectively reduce turn-on consumption, makes the switching device working stability reliable, promotes efficient.

Claims

1. the resonant circuit of an electromagnetic oven; Comprise current rectifying and wave filtering circuit (2), resonant circuit (5), power tube (3), said current rectifying and wave filtering circuit (2) input connects civil power, and said resonant circuit (5) one ends connect the output of current rectifying and wave filtering circuit (2); The other end connects power tube (3); It is characterized in that said resonant circuit (5) comprises inductance coil L1 and resonant capacitance C1, C2 and C3, inductance coil L1 and resonant capacitance C2 form parallel circuits (4); One end of parallel circuits (4) is connected with resonant capacitance C1, and the other end is connected with the resonant capacitance C3 of the C utmost point that is connected across power tube (3) with E utmost point two ends.

2. the resonant circuit of electromagnetic oven according to claim 1 is characterized in that, said resonant capacitance C1 both can pass through low frequency signal, also can pass through high-frequency signal.

3. the resonant circuit of electromagnetic oven according to claim 2 is characterized in that, said low frequency signal is the power frequency component of 100Hz or 120Hz.

4. the resonant circuit of electromagnetic oven according to claim 1 is characterized in that said resonant capacitance C2 and/or C3 are for can be through the electric capacity of high-frequency signal.

5. according to the resonant circuit of claim 2 or 4 described electromagnetic ovens, it is characterized in that said high-frequency signal is the above power frequency component of 20KHz.