阅读说明：本技术 高频感应加热串联谐振软开关逆变控制方法 (High-frequency induction heating series resonance soft switch inversion control method ) 是由 于占东 付莹 邢星 于震 张鹏 于 2019-10-30 设计创作，主要内容包括：一种高频感应加热串联谐振软开关逆变控制方法,属于软开关逆变控制技术领域。本发明针对现有感应加热逆变领域采用移相谐振方波实现软开关的逆变控制,其硬开关造成的发热存在于同一开关管模块中,散热难度大的问题。软开关逆变控制方法采用与逆变电源主回路频率相同的三角波获得对开关器件的驱动脉冲；以二分之一三角波幅值作为基准,结合设定的调整幅值选定两个基准幅值；使三角波幅值与其中一个基准幅值的比较结果作为一个桥臂上两个开关器件的触发电平,使三角波幅值与其中另一个基准幅值的比较结果作为另一个桥臂上两个开关器件的触发电平；每个桥臂上两个开关器件的逻辑相反。本发明用于实现感应加热串联谐振软开关的逆变。(A high-frequency induction heating series resonance soft switch inversion control method belongs to the technical field of soft switch inversion control. The invention aims at the problems that in the existing induction heating inversion field, inversion control of a soft switch is realized by adopting phase-shifting resonance square waves, heating caused by hard switching of the soft switch exists in the same switch tube module, and the heat dissipation difficulty is high. The soft switching inversion control method adopts triangular waves with the same frequency as the main loop of the inversion power supply to obtain driving pulses for a switching device; selecting two reference amplitudes by taking the amplitude of the half triangular wave as a reference and combining with a set adjustment amplitude; enabling the comparison result of the triangular wave amplitude and one of the reference amplitudes to serve as the trigger levels of the two switching devices on one bridge arm, and enabling the comparison result of the triangular wave amplitude and the other reference amplitude to serve as the trigger levels of the two switching devices on the other bridge arm; the logic of the two switching devices on each bridge arm is opposite. The invention is used for realizing inversion of the induction heating series resonance soft switch.)

1. A high-frequency induction heating series resonance soft switching inversion control method is characterized in that an inversion power supply main loop controlled by the inversion control method comprises a single-phase full-bridge type inversion circuit, the single-phase full-bridge type inversion circuit comprises two bridge arms, and each bridge arm comprises two switching devices; the main loop of the inverter works in an inductive resonance state;

the soft switching inversion control method adopts triangular waves with the same frequency as the main loop of the inversion power supply to obtain driving pulses for a switching device; selecting two reference amplitudes by taking the amplitude of the half triangular wave as a reference and combining with a set adjustment amplitude; the comparison result of the triangular wave amplitude and one of the reference amplitudes is used as the trigger level of two switching devices on one bridge arm, and the comparison result of the triangular wave amplitude and the other reference amplitude is used as the trigger level of two switching devices on the other bridge arm, so that the soft switching control of four switching devices in the main loop of the inverter power supply is realized; the logic of the two switching devices on each bridge arm is opposite.

2. The high-frequency induction heating series resonance soft-switching inverter control method according to claim 1,

setting two switching devices on one bridge arm as VT1 and VT2, and setting two switching devices on the other bridge arm as VT3 and VT 4; the trigger levels comprise level signals triggering VT1, VT2, VT3 and VT 4;

setting one-half triangular wave amplitude value as T₀If the amplitude is adjusted to be delta, the amplitude of the triangular wave is greater than T₀+ Δ, VT1 is high, VT2 is low; the amplitude of the triangular wave is lower than T₀+ Δ, VT1 is low, VT2 is high; setting dead time τ between VT1 and VT2₀；

The amplitude of the triangular wave is greater than T₀At- Δ, VT4 is high and VT3 is low; the amplitude of the triangular wave is lower than T₀At- Δ, VT4 is low and VT3 is high; setting dead time τ between VT3 and VT4₀；

The high level corresponds to the turn-on of the corresponding switching device and the low level corresponds to the turn-off of the corresponding switching device.

3. The high-frequency induction heating series resonance soft-switching inverter control method according to claim 2,

the method for calculating the output power of the main loop of the inverter power supply in the control method comprises the following steps:

when the main loop of the inverter works in an inductive resonance state, the fundamental frequency component U of the output voltage is inverted_AB0Leading load current I_ABPhase β/2, where β is the phase difference between VT1 and VT 3; then the output voltage U is inverted_ABThe fourier expression of (a) is:

in the formula of U_dThe direct current voltage of the main loop of the inverter power supply is used, and omega is the angular frequency of the inverter fundamental wave;

U_ABfundamental component U of (t)_AB0(t) is:

U_AB0(t) effective value U_AB0Comprises the following steps:

let the fundamental current phase shift angle phi₁Comprises the following steps:

in the formula₀The phase angle between the load current and the inverted output voltage square wave;

then the load current I_ABEffective value I of fundamental component of (t)_AB0Comprises the following steps:

wherein Z is the equivalent impedance of the load;

the output power P of the main loop of the inverter is:

4. the high-frequency induction heating series resonance soft-switching inversion control method according to claim 3, wherein when the phase difference β between VT1 and VT3 is 0, the maximum value P of the output power P of the main loop of the inversion power supply is_mComprises the following steps:

5. the high-frequency induction heating series resonance soft-switching inversion control method according to claim 4, wherein a per unit value of active power of a main loop of the inverter power supply

6. the high-frequency induction heating series resonance soft-switching inverter control method according to claim 5, wherein when phi is₀When the content is equal to 0, the content,

Technical Field

The invention relates to a high-frequency induction heating series resonance soft switch inversion control method, and belongs to the technical field of soft switch inversion control.

Background

Induction heating, also known as electromagnetic induction heating, uses the principle of electromagnetic induction to generate current inside a material to be heated, and relies on the energy of eddy currents to achieve the purpose of heating, and is an advanced heating technology. The induction heating has the advantages of high heating efficiency, high speed, good controllability, easy realization of mechanization and automation and the like, so that the induction heating is widely applied to the hot processing technologies of smelting, welding, heat treatment, hot forging, epitaxial processing and the like in the industrial fields of metallurgy, machinery, electronics and the like, and has shown more and more extensive application prospects.

At present, in the field of induction heating inversion, phase-shift resonance square waves are mostly adopted to realize inversion control of soft switches, and in the method, under the condition that the power regulation process of a system is detuned, when large current is generated and hard turn-off is carried out, the heating caused by hard switches is generally born by switch tubes of the same module on the same bridge arm, so that the defect of high heat dissipation difficulty exists, and further the reliability of the system can be influenced.

Disclosure of Invention

The invention provides a high-frequency induction heating series resonance soft switch inversion control method, aiming at the problems that in the existing induction heating inversion field, phase-shift resonance square waves are adopted to realize inversion control of a soft switch, heating caused by hard switching of the soft switch exists in the same switch tube module, and the heat dissipation difficulty is high.

The invention relates to a high-frequency induction heating series resonance soft switching inversion control method.A main circuit of an inversion power supply controlled by the inversion control method comprises a single-phase full-bridge inverter circuit, wherein the single-phase full-bridge inverter circuit comprises two bridge arms, and each bridge arm comprises two switching devices; the main loop of the inverter works in an inductive resonance state;

the soft switching inversion control method adopts triangular waves with the same frequency as the main loop of the inversion power supply to obtain driving pulses for a switching device; selecting two reference amplitudes by taking the amplitude of the half triangular wave as a reference and combining with a set adjustment amplitude; the comparison result of the triangular wave amplitude and one of the reference amplitudes is used as the trigger level of two switching devices on one bridge arm, and the comparison result of the triangular wave amplitude and the other reference amplitude is used as the trigger level of two switching devices on the other bridge arm, so that the soft switching control of four switching devices in the main loop of the inverter power supply is realized; the logic of the two switching devices on each bridge arm is opposite.

According to the high-frequency induction heating series resonance soft switching inversion control method, two switching devices on one bridge arm are set to be VT1 and VT2, and two switching devices on the other bridge arm are set to be VT3 and VT 4; the trigger levels comprise level signals triggering VT1, VT2, VT3 and VT 4;

setting one-half triangular wave amplitude value as T₀If the amplitude is adjusted to be delta, the amplitude of the triangular wave is greater than T₀+ Δ, VT1 is high, VT2 is low; the amplitude of the triangular wave is lower than T₀+ Δ, VT1 is low, VT2 is high; setting dead time τ between VT1 and VT2₀；

The amplitude of the triangular wave is greater than T₀At- Δ, VT4 is high and VT3 is low; the amplitude of the triangular wave is lower than T₀At- Δ, VT4 is low and VT3 is high; setting dead time τ between VT3 and VT4₀；

The high level corresponds to the turn-on of the corresponding switching device and the low level corresponds to the turn-off of the corresponding switching device. According to the high-frequency induction heating series resonance soft switch inversion control method, the output power calculation method of the main loop of the inversion power supply in the control method comprises the following steps:

when the main loop of the inverter works in an inductive resonance state, the fundamental frequency component U of the output voltage is inverted_AB0Leading load current I_ABPhase β/2, where β is the phase difference between VT1 and VT 3; then the output voltage U is inverted_ABThe fourier expression of (a) is:

in the formula of U_dThe direct current voltage of the main loop of the inverter power supply is used, and omega is the angular frequency of the inverter fundamental wave;

U_ABfundamental component U of (t)_AB0(t) is:

U_AB0(t) effective value U_AB0Comprises the following steps:

let the fundamental current phase shift angle phi₁Comprises the following steps:

in the formula₀The phase angle between the load current and the inverted output voltage square wave;

then the load current I_ABEffective value I of fundamental component of (t)_AB0Comprises the following steps:

wherein Z is the equivalent impedance of the load;

the output power P of the main loop of the inverter is:

according to the high-frequency induction heating series resonance soft switching inversion control method, when the phase difference beta of VT1 and VT3 is 0, the maximum value P of the output power P of the main loop of the inversion power supply is_mComprises the following steps:

according to the high-frequency induction heating series resonance soft switch inversion control method, the per unit value of the active power of the main loop of the inversion power supply

Comprises the following steps:

according to the high-frequency induction heating series resonance soft switching inversion control method of the invention, when phi₀When the content is equal to 0, the content,

the invention has the beneficial effects that: the invention realizes the inversion of the induction heating series resonance soft switch by a pulse generation and control method different from the common phase-shifting resonance square wave inversion. When the inversion main loop works in a series resonance state, the method can obtain the same control effect as the traditional method; when the power adjusting process of the system is detuned and large current is generated to be turned off hard, the heating caused by the hard switch is jointly born by the two modules where the switch tube is located, and the heat dissipation effect is better.

Drawings

FIG. 1 is a schematic diagram of a driving pulse signal generation process of the high-frequency induction heating series resonance soft-switching inversion control method according to the present invention;

fig. 2 is a schematic circuit structure diagram of the main circuit of the inverter power supply;

FIG. 3 is a graph of the relationship between the per unit value of the active power of the main loop of the inverter and the angle beta;

fig. 4 is a timing chart of inverter circuit control in a conventional phase shift control method.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.