CN103904871B - The control method of high-frequency heating power switching tube protection circuit - Google Patents
The control method of high-frequency heating power switching tube protection circuit Download PDFInfo
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- CN103904871B CN103904871B CN201410114897.0A CN201410114897A CN103904871B CN 103904871 B CN103904871 B CN 103904871B CN 201410114897 A CN201410114897 A CN 201410114897A CN 103904871 B CN103904871 B CN 103904871B
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Abstract
The invention discloses the control method of a kind of high-frequency heating power switching tube protection circuit; the time of overvoltage in cycle according to resonant capacitor voltage waveform and a cycle; calculate the crest voltage of resonant capacitance, take corresponding control measure according to the size of crest voltage.The present invention, by detecting the duration of resonant capacitance overvoltage, calculates overvoltage peak value, and the size for overvoltage peak value uses different control strategies, and rate switching tube is realized protection.Circuit of the present invention is simple, resonance potential overvoltage value can be quantified, and take corresponding control strategy, and safeguard measure is safe and reliable.
Description
[technical field]
The present invention relates to Switching Power Supply, particularly relate to the control of a kind of high-frequency heating power switching tube protection circuit
Method.
[background technology]
Existing high-frequency heating power typically consists of the following components, rectification filtering part part, by the city of input
Electric rectification also filters high-frequency signal, it is provided that to the D/C voltage that rear class is correct.Switch sections, typically by an IGBT
Constitute single tube antiresonant circuit or two IGBT constitute half-bridge double-tube series resonance circuit.Resonance portion, by
Resonant capacitance and leakage transformer or stone or metal plate for standing a stove on as a precaution against fire coils connected in series or in parallel constitute.Output part, by voltage-multiplying circuit structure
Become to drive microwave oven magnetic or by magnetic induction heating load.Control part, by sampled input voltage,
Current signal, it is provided that correct PWM, PFM signal, drives IGBT work.Protection part, by defeated
The detection entering the signals such as voltage, current signal, resonant capacitor voltage realizes the protection to power switch pipe.
Fig. 1 is single tube parallel resonance high-frequency heating power power section schematic diagram.In FIG, Vin+, Vin-
For the filtered D/C voltage of AC input rectifying, T1 is applied to during electromagnetic oven be the stone or metal plate for standing a stove on as a precaution against fire coil of electromagnetic oven, should
It it is the primary coil of boosting leakage transformer when micro-wave oven.RL is load, and being applied to during electromagnetic oven is pot
Even load, be applied to during micro-wave oven be secondary high pressure winding rectification rear drive magnetron load.C1 is resonance
Electric capacity, Q1 is switching tube.Voltage after rectification flows through T1 and C1 by Q1 copped wave, shape through Vin+, Vin-
Become HF switch voltage, pass to load by T1.
C1 and T1 constitutes a shunt-resonant circuit, when Q1 turns off, C1 and T1 resonance, and complete energy and hand over
Changing, its waveform is approximately sinusoidal wave half-wave, as shown in Figure 2.
Fig. 3 is two-tube half bridge series resonance high-frequency heating power power section schematic diagram.In fig. 2, Q1,
Q2 is switching tube, and T1 is applied to during electromagnetic oven be the stone or metal plate for standing a stove on as a precaution against fire coil of electromagnetic oven, for boosting when being applied to micro-wave oven
The primary coil of leakage transformer.RL is load, and being applied to during electromagnetic oven is pot even load, is applied to microwave
It it is the magnetron load of secondary high pressure winding rectification rear drive during stove.C1 is resonant capacitance, and C2 is capacitance,
R is resonant capacitor voltage sampling resistor, obtain after the rectified filtering of ac input voltage DC input voltage vin+,
Vin-, after the temporary ripple of switching tube Q1, Q2, the voltage after copped wave, under resonant component T1, C1 effect, is formed
Resonance, passes to load through T1.
C1 and T1 constitutes series resonant tank, and the resonance potential on resonant capacitance is through capacitance, at sampling electricity
As shown in Figure 4, its waveform is approximate sine wave to the voltage waveform obtained on resistance R.
Fig. 5 is the testing circuit of the high-frequency heating power shown in Fig. 1, employs two comparators humorous to detect
Shake the voltage of electric capacity C1, and the output of two comparators is respectively connected to PWM control system, to realize power
The overvoltage of switching tube or overcurrent protection, PWM control system is including at least after PWM generator, AC input rectifying
Voltage and electricity current sample, Digital PWM loop and communication module.Communication module is used for receiving chain of command
The power instruction that plate sends, and power instruction is sent to digitize loop, digitlization loop is real by calculating
Error between the power instruction that border input power and control panel send, controls the service time Ton of PWM.Two
Individual comparator sets different voltage fiducial values respectively, and a comparator reference magnitude of voltage sets relatively low,
After this comparator is triggered by overvoltage, PWM control system reduces the service time Ton of switching tube, another
The reference voltage value of comparator sets relatively high, after this comparator is triggered, then and on-off switching tube
Pwm signal.This control method circuit is complicated, it is impossible to realize the quantization of resonant capacitor voltage, the effect of control
It is not easy to assessment.
[summary of the invention]
The technical problem to be solved in the present invention is to provide the control of a kind of high-frequency heating power switching tube protection circuit
Method, testing circuit is simple, can the overvoltage value of resonant capacitance be quantified, in order to take to control accordingly to arrange
Execute and power switch pipe is realized protection.
In order to solve above-mentioned technical problem, the technical solution used in the present invention is, a kind of high-frequency heating power is opened
Close the control method of tube protective circuit, according to overvoltage in cycle of resonant capacitor voltage waveform and a cycle
Time, calculate the crest voltage of resonant capacitance, take to control accordingly to arrange according to the size of crest voltage
Execute.
Above-described control method, the crest voltage Vpeak of resonant capacitance is obtained by following formula:
Vpeak=Vref/cos(dt/T×90°)；
Wherein, Vref is reference voltage, and dt is the time of the overvoltage in one voltage waveform of resonant capacitance,
T is the positive half period of resonant capacitor voltage waveform.
Above-described control method, high-frequency heating power is single tube parallel resonance high-frequency heating power, when humorous
Shake the crest voltage of electric capacity more than the first setting value time, reduce the service time of switching tube；When resonant capacitance
When crest voltage is more than the second setting value, the pwm control signal of on-off switching tube.
Above-described control method, the value of the cycle T of resonant capacitor voltage waveform is the shutoff of switching tube
Time.
Above-described control method, the voltage of resonant capacitance is obtained from the two ends of switching tube by sample circuit,
The voltage signal output end of sample circuit connects the first input end of comparator, and the second input of comparator terminates institute
The reference voltage stated, the output termination PWM control system of comparator；The time of overvoltage is obtained by comparator
Go out.
Above-described control method, high-frequency heating power is two-tube half bridge series resonance high-frequency heating power,
When the crest voltage of resonant capacitance is more than the first setting value, reduce the cycle of switching tube pwm control signal；
When the crest voltage of resonant capacitance is more than the second setting value, the pwm control signal of on-off switching tube.
Above-described control method, the value of the cycle T of resonant capacitor voltage waveform is switching tube PWM control
The half period of signal processed.
Above-described control method, the voltage of resonant capacitance is obtained from the two ends of resonant capacitance by sample circuit
, the voltage signal output end of sample circuit connects the first input end of comparator, the second input of comparator
Connect described reference voltage, the output termination PWM control system of comparator；The time of overvoltage is by comparing
Device draws.
The present invention, by detecting the duration of resonant capacitance overvoltage, calculates overvoltage peak value, according to mistake
The size of voltage peak uses different control strategies, and rate switching tube is realized protection.Circuit of the present invention letter
Single, resonance potential overvoltage value can be quantified, and take corresponding control strategy, safeguard measure is safe and reliable.
[accompanying drawing explanation]
The present invention is further detailed explanation with detailed description of the invention below in conjunction with the accompanying drawings.
Fig. 1 is the schematic diagram of prior art single tube parallel resonance high-frequency heating power power section circuit.
Fig. 2 is the voltage oscillogram of contactor pipe collector shown in Fig. 1.
Fig. 3 is the schematic diagram of prior art two-tube half bridge series resonance high-frequency heating power power section circuit.
Fig. 4 is the ohmically voltage oscillogram of circuit sampling shown in Fig. 3.
Fig. 5 is the schematic diagram of prior art high-frequency heating power testing circuit.
Fig. 6 is the schematic diagram of the embodiment of the present invention.
Fig. 7 is the principle of the embodiment of the present invention 1 single tube parallel resonance high-frequency heating power switching tube protection circuit
Figure.
Fig. 8 is the embodiment of the present invention 1 two-tube half bridge series resonance high-frequency heating power switching tube protection circuit
Schematic diagram.
[detailed description of the invention]
As shown in Figure 6, t1 to t4 interval is the half-wave voltage of a sine wave, and referred to as A waveform, t5 is extremely
T8 interval is the half-wave voltage of another sine wave, referred to as B waveform.A waveform is identical with the cycle of B waveform
The amplitude being T, B waveform is greater than A waveform.
Vref is for setting reference voltage.The voltage magnitude of A waveform is little, and it exceedes the part of reference voltage the most relatively
Little, the time of overage is that t2 to t3 is interval, hereinafter simply referred to as dtA.The voltage magnitude of B waveform is big,
Its part exceeding reference voltage is the biggest, and the time of overage is that t6 to t7 is interval, hereinafter simply referred to as
dtB.From the graph, it is apparent that because the amplitude of B waveform is higher than A waveform, dtB is also significantly greater than dtA.
The sinusoidal wave cycle is T, and reference voltage is Vref, and the overvoltage time is dtA and dtB, for sine wave
Crest voltage Peak_A and Peak_B of A waveform and B waveform can be calculated by following formula:
Peak_A=Vref/cos (dtA/T × 90 °) formula 1
Or PeaK_A=Vref/cos{ [(t3-t2)/2]/[t3-t1-(t3-t2)/2] formula 2
Peak_B=Vref/cos (dtB/T × 90 °) formula 3
Or PeaK_B=Vref/cos{ [(t7-t6)/2]/[t7-t5-(t7-t6)/2] formula 4
For the single tube parallel resonance high-frequency heating power circuit shown in Fig. 1, sinusoidal wave half wave cycles is for opening
Closing the turn-off time Toff of pipe, overvoltage time (t3-t2) or (t7-t6) can be drawn by comparator, therefore
Peak value Peak_A and Peak_B of overvoltage can be calculated by formula 1 or formula 2.
For half bridge series resonance high-frequency heating power circuit two-tube shown in Fig. 2, sinusoidal wave cycle T is
In the cycle of the pwm control signal of switching tube, overvoltage time (t3-t2) or (t7-t6) can be obtained by comparator
Go out, thus the peak value of overvoltage can be calculated by formula 1 or formula 2.
Obtain peak overvoltage quantized value, different relative strategies can have been used, such as shown in Fig. 1
Single tube parallel resonance high-frequency heating power circuit, when crest voltage less than switching tube maximum working voltage 85%
Time, reduce the service time Ton of switching tube, and assess within the response time of loop, whether regulation reaches mesh
, if crest voltage does not decline, then continue to reduce service time Ton, if crest voltage exceedes switch
Pipe maximum working voltage 95% time, then can directly turn off pwm control signal.
For the two-tube half bridge series resonance high-frequency heating power circuit shown in Fig. 3, equally, when overvoltage exists
Can system can be in tolerance range, such as, when overvoltage is less than the 85% of switching tube maximum working voltage, reduce
The cycle of the pwm control signal of switching tube, and assess within the response time of loop, whether overvoltage declines,
If crest voltage does not decline, then continue to reduce the cycle of the pwm control signal of switching tube, if peak value
Voltage exceedes the certain value of default, the then pwm control signal of direct on-off switching tube.
Fig. 7 shows embodiment of the present invention application on single tube parallel resonance high-frequency heating power circuit, opens
The voltage (being equal to the C1 voltage of resonant capacitance) closing pipe Q1 is delivered to by after divider resistance R1, R2 dividing potential drop
One input of comparator U1, reference voltage Vref is connected to another input of comparator, works as overvoltage
During generation, PWM control system metering PWM turn-off time Toff and the overvoltage time of comparator, calculate
Overvoltage value, produces regulation error signal according to the size of crest voltage, and error signal size determines that PWM opens
The value that the logical time reduces, when crest voltage is more than the 85% of switching tube maximum working voltage, uses and reduces
The strategy of PWM service time Ton, when crest voltage is more than switching tube maximum working voltage 95%, the most directly
The pwm control signal of on-off switching tube.Owing to above-mentioned PWM control system is typically made up of single-chip microcomputer, meter
Calculation ability is more weak, the value of 1/cos θ can be write tabular value as, and the value of 1/cos θ is drawn by look-up method.
Fig. 8 shows the present invention application at two-tube half bridge series resonance high-frequency heating power circuit, resonance electricity
The voltage of appearance C1 is by delivering to an input of comparator U1 after divider resistance R1, R2 dividing potential drop, with reference to electricity
Pressure Vref is connected to another input of comparator, when overvoltage occurs, PWM control system metering switch pipe
Cycle of pwm control signal and the overvoltage time of comparator, calculate peak voltage, as it has been described above,
Equally the cycle being to reduce pwm control signal is taked also to be off PWM according to the size of crest voltage
Control signal.
Above example circuit of the present invention is simple, resonance potential overvoltage value can be quantified, and take to control accordingly
System strategy, safe and reliable.
Claims (6)
1. the control method of a high-frequency heating power switching tube protection circuit, it is characterised in that according to resonance
The cycle T of capacitance voltage waveform and time of overvoltage in the cycle, calculate the peak electricity of resonant capacitance
Pressure Vpeak, takes corresponding control measure according to the size of crest voltage Vpeak；The peak value of resonant capacitance
Voltage Vpeak is obtained by following formula:
Vpeak=Vref/cos (dt/T × 90 °)；
Wherein, Vref is reference voltage, and dt is the time of the overvoltage in one voltage waveform of resonant capacitance.
Control method the most according to claim 1, it is characterised in that high-frequency heating power be single tube also
Connection resonant frequencies heating power supply, when the crest voltage of resonant capacitance is more than the first setting value, reduces switching tube
Service time；When the crest voltage of resonant capacitance is more than the second setting value, the PWM control of on-off switching tube
Signal processed.
Control method the most according to claim 2, it is characterised in that the week of resonant capacitor voltage waveform
The value of phase T is the turn-off time of switching tube.
Control method the most according to claim 2, it is characterised in that the voltage of resonant capacitance is by adopting
Sample circuit obtains from the two ends of switching tube, and the voltage signal output end of sample circuit connects the first input of comparator
End, the reference voltage described in the second input termination of comparator, the output termination PWM control system of comparator；
The time of overvoltage is drawn by comparator.
Control method the most according to claim 1, it is characterised in that high-frequency heating power is two-tube half
Bridge series resonance high-frequency heating power, when the crest voltage of resonant capacitance is more than the first setting value, reduction is opened
Close the cycle of pipe pwm control signal；When the crest voltage of resonant capacitance is more than the second setting value, closes and disconnect
Close the pwm control signal of pipe.
Control method the most according to claim 5, it is characterised in that the voltage of resonant capacitance is by adopting
Sample circuit obtains from the two ends of resonant capacitance, and it is first defeated that the voltage signal output end of sample circuit connects comparator
Entering end, the reference voltage described in the second input termination of comparator, the output termination PWM of comparator controls system
System；The time of overvoltage is drawn by comparator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410114897.0A CN103904871B (en) | 2014-03-25 | 2014-03-25 | The control method of high-frequency heating power switching tube protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410114897.0A CN103904871B (en) | 2014-03-25 | 2014-03-25 | The control method of high-frequency heating power switching tube protection circuit |
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| CN103904871B true CN103904871B (en) | 2016-09-07 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106572552B (en) * | 2015-10-13 | 2019-09-27 | 佛山市顺德区美的电热电器制造有限公司 | The control method and device of the service time of power switch tube in electromagnetic heating system |
| CN107920398B (en) * | 2016-10-08 | 2020-11-27 | 佛山市顺德区美的电热电器制造有限公司 | Control method and device of electromagnetic equipment and electromagnetic equipment |
| CN109818328B (en) * | 2019-03-19 | 2020-09-11 | 浪潮商用机器有限公司 | Overvoltage protection circuit of switching power supply |
| CN111193383A (en) * | 2020-01-22 | 2020-05-22 | 维沃移动通信有限公司 | Power control circuit and electronic device |
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| JP4432498B2 (en) * | 2004-01-14 | 2010-03-17 | 富士電機システムズ株式会社 | Induction heating inverter controller |
| CN201430703Y (en) * | 2009-06-23 | 2010-03-24 | 宝应县恒泰电器设备厂 | Electromagnetic heating circuit |
| FR2958491A1 (en) * | 2010-03-31 | 2011-10-07 | Fagorbrandt Sas | Inverter feeding device protecting method for induction cooking apparatus, involves forcing control signal to value to set switch in ON state when voltage value greater than maximum threshold value is detected between terminals of switch |
| CN102281658A (en) * | 2011-07-25 | 2011-12-14 | 深圳和而泰智能控制股份有限公司 | Synchronous signal acquiring circuit and control device for induction cooker and induction cooker |
| CN203166499U (en) * | 2013-03-25 | 2013-08-28 | 长沙理工大学 | IGBT overvoltage protection circuit of electromagnetic oven |
| CN103296911A (en) * | 2013-06-12 | 2013-09-11 | 肖国选 | Single pipe resonant type soft switch inversion circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101944855B (en) * | 2009-07-07 | 2012-11-28 | 深圳市鑫汇科科技有限公司 | Digital control power supply converter for kitchen range |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4432498B2 (en) * | 2004-01-14 | 2010-03-17 | 富士電機システムズ株式会社 | Induction heating inverter controller |
| CN201430703Y (en) * | 2009-06-23 | 2010-03-24 | 宝应县恒泰电器设备厂 | Electromagnetic heating circuit |
| FR2958491A1 (en) * | 2010-03-31 | 2011-10-07 | Fagorbrandt Sas | Inverter feeding device protecting method for induction cooking apparatus, involves forcing control signal to value to set switch in ON state when voltage value greater than maximum threshold value is detected between terminals of switch |
| CN102281658A (en) * | 2011-07-25 | 2011-12-14 | 深圳和而泰智能控制股份有限公司 | Synchronous signal acquiring circuit and control device for induction cooker and induction cooker |
| CN203166499U (en) * | 2013-03-25 | 2013-08-28 | 长沙理工大学 | IGBT overvoltage protection circuit of electromagnetic oven |
| CN103296911A (en) * | 2013-06-12 | 2013-09-11 | 肖国选 | Single pipe resonant type soft switch inversion circuit |
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