PFC circuit and electric flame suitable for direct current and alternating current

Abstract

The application discloses a PFC circuit and an electric flame stove suitable for direct current and alternating current, comprising a voltage switching control module, a filter module, an inverter voltage boosting module, a full-bridge rectifying module and a power factor correction module. The voltage switching control module detects input voltage and controls the on-off of the filter module and the inverter voltage boosting module respectively, realizing the adaptation of 48V direct current and 220V alternating current voltage input. The power factor correction module adopts a Boost (voltage boosting) type active PFC topology, the high-frequency on-off control of the switching tube Q7 / Q8 is realized through the control chip U2 / U3, the input current waveform follows the input voltage waveform, the power factor is improved to above 0.95, the switching tube Q8 is adopted to replace the diode in the prior art, there is no voltage and current loss when the switching tube is turned on, the stable current and voltage output are ensured, the voltage / current waveform is consistent, and the power factor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to electric flame hobs. BACKGROUND

[0002] The electric flame hob is a new type of flame generation method, which uses two different electrodes to generate an electric field by high-voltage breakdown of gas flow, and the gas flow collides with the electrons in the electric field to ionize the gas molecules to form plasma, which has a high temperature of more than 1,000 degrees Celsius and is used to heat a pot. The electric flame hobs appearing on the market are also called electric fire hobs, electric fire hobs, electric flame hobs, electric fire hobs, electric fire hobs, plasma hobs, etc. The above-mentioned hobs all use high-voltage breakdown to excite plasma for heating a pot.

[0003] However, the existing technology of household electric flame hobs can only meet the input of 220V alternating voltage, and for users who need to have meals outdoors, a 48V DC battery needs to be developed, which undoubtedly increases the additional use cost of the user. In addition, the existing technology of electric flame hobs is low in efficiency, and the efficiency needs to be improved through improvement of the circuit.

[0004] The present application aims to provide an electric flame hob that can be used with mains electricity and storage batteries, and has high efficiency. SUMMARY

[0005] The present application aims to provide an electric flame hob that can be used with mains electricity and storage batteries, and has high efficiency.

[0006] A PFC circuit suitable for DC and AC power supply includes a voltage switching control module, a filter module, an inverter boost module, a full-bridge rectifier module and a power factor correction module.

[0007] The voltage switching control module includes a normally closed relay RLY1, a normally closed relay RLY2, a voltage stabilizing tube ZD1, a resistor R2, a diode D5 and a diode D6. The anode of the diode D5 is connected to the circuit input end CN1, the anode of the diode D6 is connected to the circuit input end CN2, the common node of the cathode of the diode D5 and the cathode of the diode D6 is connected to the cathode of the voltage stabilizing tube ZD1, the anode of the voltage stabilizing tube ZD1 is connected to one end of the coils of the normally closed relays RLY1 and RLY2, the gates of the switching tubes Q1 and Q2 through the resistor R2, and the other end of the coils of the normally closed relays RLY1 and RLY2 is grounded.

[0008] One input terminal of the filter module is connected with the circuit input terminal CN1 through the source and drain of the switch tube Q1, and the other input terminal is connected with the circuit input terminal CN2 through the source and drain of the switch tube Q2, and the two output terminals of the filter module are connected with the two input terminals of the full-bridge rectifier module;

[0009] The inverter boosting module comprises a transformer T1 and an inverter bridge composed of switch tubes Q3, Q4, Q5 and Q6, the two input terminals of the full-bridge rectifier module are also connected with the two ends of the secondary coil of the transformer T1, the two ends of the primary coil of the transformer T1 are respectively connected with the two AC output terminals of the inverter bridge, one DC input terminal of the inverter bridge is connected with the circuit input terminal CN1 through the normally closed relay RLY1, and the other DC input terminal is connected with the circuit input terminal CN2 through the normally closed relay RLY2;

[0010] Preferably, the filter module comprises a common-mode inductor L1, a differential-mode capacitor C1, a differential-mode capacitor C2 and an adjustable resistor R1.

[0011] One input terminal of the common-mode inductor L1 is connected with the circuit input terminal CN1 through the switch tube Q1, and the other input terminal is connected with the circuit input terminal CN2 through the switch tube Q2, and the two output terminals of the common-mode inductor L1 are respectively connected with the two input terminals of the full-bridge rectifier module.

[0012] The differential-mode capacitor C2 and the adjustable resistor R1 are both connected in parallel with the two input terminals of the common-mode inductor L1, and the differential-mode capacitor C1 is connected in parallel with the two output terminals of the common-mode inductor L1.

[0013] Preferably, the power factor correction module comprises an inductor L2, a filter capacitor C22, a switch tube Q7 and a switch tube Q8, one end of the inductor L2 is connected with the output terminal of the full-bridge rectifier module, the other end of the inductor L2 is respectively connected with the drain of the switch tube Q7 and the drain of the switch tube Q8, the source of the switch tube Q8 is connected with one end of the filter capacitor C22, and the source of the switch tube Q7 and the other end of the filter capacitor C22 are both grounded.

[0014] Preferably, the power factor correction module further comprises a control chip U3 and a control chip U2, one control output pin of the control chip U3 is connected with the gate of the switch tube Q7 through the resistor R14, the other control output pin is connected with the gate of the switch tube Q8 through the resistor R18, and the control output pin of the control chip U2 is connected with the control signal input terminal of the control chip U3 through the resistor R10.

[0015] Preferably, the output terminal of the power factor correction module is connected with the sampling pin of the control chip U2 through the resistors R23, R24 and R25 connected in series.

[0016] Preferably, the power factor correction module further comprises a diode D11, an anode of the diode D11 is connected to an output end of the full-bridge rectifier module, and a cathode of the diode D11 is connected to the filter capacitor C22;

[0017] Preferably, the voltage stabilizing tube ZD1 has a voltage resistance value of 200V, and an anode thereof is further connected to one end of the capacitor C5 through the resistor R2, and the other end of the capacitor C5 is grounded.

[0018] The application further provides an electric flame stove, which comprises the PFC circuit applicable to direct current and alternating current as described in any one of the above.

[0019] Compared with the prior art, the application has the following advantages:

[0020] The voltage switching control module detects an input voltage, and controls on-off of the filter module and the inverter voltage boosting module respectively, so that the adaptation of 48V direct current and 220V alternating current is realized.

[0021] The power factor correction module adopts a Boost (voltage boosting) type active PFC topology, high-frequency on-off control of the switching tube Q7 and the switching tube Q8 is realized through the control chips U2 and U3, the double goals of "input current waveform following input voltage waveform" and "output voltage stability" are realized, finally, the input pulsed direct current voltage is boosted and stabilized as DC380V, and the power factor is improved to above 0.95.

[0022] The switching tube Q8 is adopted instead of the diode in the prior art, there is no voltage and current loss when the switching tube is turned on, stable current and voltage output are ensured, so that the voltage and current waveforms are consistent, and the power factor is improved.

[0023] Additional aspects and advantages of the application will be described in part below with reference to the description, will become apparent from the description, or will be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0025] Figure 1 is a circuit schematic diagram of the application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.

[0027] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0028] In addition, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements, it can be wireless connection, or wired connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] In addition, the technical features involved in the different embodiments of the present application described later can be combined with each other as long as they do not conflict with each other.

[0030] Please refer to Figure 1 The PFC circuit disclosed in the embodiments of the present application is the core of realizing the dual-input compatibility of 48V DC and 220V AC. The input type is automatically adapted by the voltage switching control module 200. After filtering, rectification and power factor correction, a stable high-voltage DC (380V) is output, which provides high-quality power supply for the ignition module and heating module of the electric flame stove. The PFC circuit of the present application is composed of five core parts: voltage switching control module 200, filtering module 100, inverter boost module 300, full-bridge rectifier module 400 and power factor correction module 500. Each module forms a closed loop link through the power node and the control signal node, ensuring that efficient electric energy conversion of "voltage adaptation -> rectification conversion -> power correction -> stable output" can be realized under two input voltages.

[0031] The voltage switching control module 200 comprises a normally closed relay RLY1, a normally closed relay RLY2, a voltage stabilizing tube ZD1, a resistor R2, a diode D5 and a diode D6. The anode of the diode D5 is connected to the circuit input end CN1, the anode of the diode D6 is connected to the circuit input end CN2, and the cathodes of the two diodes are connected to the cathode of the voltage stabilizing tube ZD1. The common node of the cathodes of the diode D5 and the diode D6 is connected to the cathode of the voltage stabilizing tube ZD1. The anode of the voltage stabilizing tube ZD1 is connected to one end of the coils of the normally closed relay RLY1 and the normally closed relay RLY2 and the gates of the switching tubes Q1 and Q2 through the resistor R2. The other ends of the coils of the normally closed relay RLY1 and the normally closed relay RLY2 are grounded.

[0032] In the embodiment, the voltage switching control module 200 comprises a normally closed relay RLY1, a normally closed relay RLY2, a voltage stabilizing tube ZD1, a resistor R2, a diode D5 and a diode D6. The anode of the diode D5 is connected to the circuit input end CN1, the anode of the diode D6 is connected to the circuit input end CN2, and the cathodes of the two diodes are connected to the cathode of the voltage stabilizing tube ZD1. The common node of the cathodes of the diode D5 and the diode D6 is connected to the cathode of the voltage stabilizing tube ZD1. The anode of the voltage stabilizing tube ZD1 is connected to one end of the coils of the normally closed relay RLY1 and the normally closed relay RLY2 and the gates of the switching tubes Q1 and Q2 through the resistor R2. The other ends of the coils of the normally closed relay RLY1 and the normally closed relay RLY2 are grounded.

[0033] The two input ends of the filter module 100 are connected to the circuit input ends CN1 and CN2 through the source and drain of the switching tube Q1 and the source and drain of the switching tube Q2. The two output ends of the filter module 100 are connected to the two input ends of the full-bridge rectifier module 400.

[0034] The inverter and booster module 300 comprises a transformer T1 and an inverter bridge composed of switching tubes Q3, Q4, Q5 and Q6. The two input ends of the full-bridge rectifier module 400 are also connected to the two ends of the secondary coil of the transformer T1. The two ends of the primary coil of the transformer T1 are connected to the two AC output ends of the inverter bridge. The two DC input ends of the inverter bridge are connected to the circuit input ends CN1 and CN2 through the normally closed relays RLY1 and RLY2.

[0035] The voltage stabilizing tube ZD1 has a voltage resistance of 200V, and the transformer T1 is a booster transformer.

[0036] When the DC input is 48V, the voltage (48V) is lower than the voltage resistance of the voltage stabilizing tube ZD1, the ZD1 is cut off, the coil of the normally closed relay RLY1, the coil of the normally closed relay RLY2, the switch tube Q1 and the switch tube Q2 are all without current or voltage, the normally closed contacts of the normally closed relay RLY1 and the normally closed relay RLY2 are all closed, and the switch tube Q1 and the switch tube Q2 are all cut off. At this time, the 48V direct current enters the inverter bridge, the alternating on-off of the switch tube Q3, Q5, the switch tube Q4 and Q6 makes the transformer T1 primary coil obtain alternating current, and the alternating current is boosted to 220V high voltage (secondary output voltage) through the transformer T1, and then the full-bridge rectifier module 400 rectifies the 220V high voltage to nearly 310V unidirectional output pulsed direct current.

[0037] When the AC input is 220V, the 219V direct current (the voltage is reduced by the diode D5 and the diode D6) is still higher than the voltage resistance of the voltage stabilizing tube ZD1 after rectification, the voltage stabilizing tube ZD1 is reversely broken down, and the voltage stabilizing tube ZD1 provides current or voltage for the coil of the normally closed relay RLY1 and the normally closed relay RLY2 and the gate of the switch tube Q1 and Q2. At this time, the normally closed relay RLY1 and the normally closed relay RLY2 are all disconnected, and the switch tube Q1 and the switch tube Q2 are all turned on. The 220V alternating current is filtered to remove common mode interference and differential mode interference through the filter module 100, and then rectified to nearly 310V unidirectional output pulsed direct current through the full-bridge rectifier module 400.

[0038] In the embodiment of the application, the filter module 100 includes a common mode inductor L1, a differential mode capacitor C1, a differential mode capacitor C2 and an adjustable resistor R1. The differential mode capacitor C2 and the adjustable resistor R1 are connected in parallel with the two input ends of the common mode inductor L1, and the differential mode capacitor C1 is connected in parallel with the two input ends of the common mode inductor L1, so as to suppress the common mode and differential mode interference on the 220V AC power input side.

[0039] In the embodiment of the present application, the power factor correction module 500 comprises an inductor L2, a filter capacitor C22, a switch tube Q7 and a switch tube Q8, one end of the inductor L2 is connected to the output end of the full-bridge rectifier module 400, the other end of the inductor L2 is connected to the source of the switch tube Q7 and the source of the switch tube Q8 respectively, the drain of the switch tube Q8 is connected to one end of the filter capacitor C22, and the drain of the switch tube Q7 and the other end of the filter capacitor C22 are both grounded; the power factor correction module 500 further comprises a control chip U3 and a control chip U2, two control output pins of the control chip U3 are connected to the gate of the switch tube Q7 and the gate of the switch tube Q8 through resistors R14 and R18 respectively, and the control output pin of the control chip U2 is connected to the control signal input end of the control chip U3 through a resistor R10; the output end of the power factor correction module 500 is connected to the sampling pin of the control chip U2 through resistors R23, R24 and R25; the power factor correction module 500 further comprises a diode D11, the anode of the diode D11 is connected to the output end of the full-bridge rectifier module 400, and the cathode of the diode D11 is connected to the filter capacitor C22.

[0040] The power factor correction module adopts a Boost (voltage boosting) type active PFC topology, and through high-frequency on-off control of the switch tubes Q7 and Q8 by the control chips U2 and U3, the dual goals of "input current waveform following input voltage waveform" and "output voltage stability" are achieved, finally the input pulsed DC voltage is boosted and stabilized to DC 380V, and the power factor is improved to above 0.95.

[0041] Specifically, the inductor L2 realizes "energy storage-energy release" in a switching period; the switch tubes Q7 and Q8 adopt staggered parallel design (double-tube alternating conduction), effectively controlling current output and voltage output; U3 is a PFC special control chip, realizing "voltage loop + current loop" double closed-loop control; U2 is a reference chip, sampling the output voltage and feeding back to U3, forming a stable voltage closed loop.

[0042] More specifically, when the switch tube Q7 is turned on and the switch tube Q8 is turned off, the current in the inductor L2 linearly rises, and the electric energy is stored in the inductor L2 in the form of magnetic energy; when the switch tube Q7 is turned off and the switch tube Q8 is turned on, the current in the inductor L2 linearly drops, the energy released and the input voltage are jointly charged to C22 through the switch tube Q8, and 380V DC is provided for the load, the switch tube Q8 has no voltage and current loss, the stable current and voltage output are ensured, and then the voltage and current waveforms are consistent; when the switch tube Q7 is turned on again and the switch tube Q8 is turned off, the inductor L2 stores energy again, at this time, the filter capacitor C22 only discharges to the load, and the output voltage is maintained; the control chip U2 samples the input current waveform and the input voltage waveform through resistors R23, R24 and R25, and the sampled actual input current signal is compared with the reference current signal generated by the voltage outer ring, a current error signal is generated and output to the PWM input pin of the control chip U3, and then the current error signal is amplified by the internal error amplifier of the control chip U3, the PWM duty cycle of U3 is directly modulated, the time of the alternating turn-on and turn-off of the switch tube Q5 and the switch tube Q6 is controlled, the average value of the actual input current strictly follows the reference current waveform, the voltage and current waveforms are similar (approximately sinusoidal), and thus the harmonics are eliminated and the power factor is improved.

[0043] The application further provides an electric flame cooker, which comprises the PFC circuit suitable for DC and AC power of any one of the above.

[0044] It is obvious for those skilled in the art that the application is not limited to the details of the above-mentioned exemplary embodiments, and the application can be implemented in other specific forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be regarded as exemplary and non-limiting, the scope of the application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the application.

Claims

1. A PFC circuit suitable for both direct current and alternating current, characterized in that, It includes a voltage switching control module, a filtering module, an inverter boost module, a full-bridge rectifier module, and a power factor correction module; The voltage switching control module includes normally closed relays RLY1 and RLY2, a Zener diode ZD1, a resistor R2, a diode D5, and a diode D6. The anode of diode D5 is connected to the circuit input terminal CN1, and the anode of diode D6 is connected to the circuit input terminal CN2. The common node of the cathodes of diodes D5 and D6 is connected to the cathode of Zener diode ZD1. The anode of Zener diode ZD1 is connected through resistor R2 to one end of the coil of normally closed relays RLY1 and RLY2, and the gate of switching transistors Q1 and Q2, respectively. The other end of the coils of normally closed relays RLY1 and RLY2 is grounded. One input terminal of the filtering module is connected to the circuit input terminal CN1 through the source and drain of the switching transistor Q1, while the other input terminal is connected to the circuit input terminal CN2 through the source and drain of the switching transistor Q2. The two output terminals of the filtering module are connected to the two input terminals of the full-bridge rectifier module. The inverter boost module includes a transformer T1 and an inverter bridge composed of switching transistors Q3, Q4, Q5, and Q6. The two input terminals of the full-bridge rectifier module are also connected to the two ends of the secondary coil of the transformer T1. The two ends of the primary coil of the transformer T1 are respectively connected to the two AC output terminals of the inverter bridge. One of the DC input terminals of the inverter bridge is connected to the circuit input terminal CN1 through a normally closed relay RLY1, and the other DC input terminal is connected to the circuit input terminal CN2 through a normally closed relay RLY2. The power factor correction module includes an inductor L2, a filter capacitor C22, a switching transistor Q7, and a switching transistor Q8. One end of the inductor L2 is connected to the output terminal of the full-bridge rectifier module, and the other end of the inductor L2 is connected to the drain of the switching transistor Q7 and the drain of the switching transistor Q8, respectively. The source of the switching transistor Q8 is connected to one end of the filter capacitor C22, and the source of the switching transistor Q7 and the other end of the filter capacitor C22 are both grounded. The power factor correction module also includes control chip U3 and control chip U2. One of the control output pins of control chip U3 is connected to the gate of switch Q7 through resistor R14, and the other control output pin is connected to the gate of switch Q8 through resistor R18. The control output pin of control chip U2 is connected to the control signal input terminal of control chip U3 through resistor R10. The output terminal of the power factor correction module is connected to the sampling pin of control chip U2 through resistors R23, R24 and R25 connected in series.

2. The PFC circuit applicable to both DC and AC power according to claim 1, characterized in that, The filtering module includes a common-mode inductor L1, a differential-mode capacitor C1, a differential-mode capacitor C2, and an adjustable resistor R1. One input terminal of the common-mode inductor L1 is connected to the circuit input terminal CN1 through a switch Q1, and the other input terminal is connected to the circuit input terminal CN2 through a switch Q2. The two output terminals of the common-mode inductor L1 are respectively connected to the two input terminals of the full-bridge rectifier module. The differential-mode capacitor C2 and the adjustable resistor R1 are both connected in parallel with the two input terminals of the common-mode inductor L1, and the differential-mode capacitor C1 is connected in parallel with the two output terminals of the common-mode inductor L1.

3. The PFC circuit applicable to both DC and AC power according to claim 1, characterized in that, The power factor correction module also includes a diode D11, the anode of which is connected to the output terminal of the full-bridge rectifier module, and the cathode of which is connected to the filter capacitor C22.

4. The PFC circuit applicable to both DC and AC power according to claim 1, characterized in that, The Zener diode ZD1 has a withstand voltage of 200V, and its anode is connected to one end of capacitor C5 through resistor R2. The other end of capacitor C5 is grounded.

5. An electric flame stove, characterized in that, The electric flame stove includes the PFC circuit applicable to both direct current and alternating current as described in any one of claims 1 to 4.

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