WO2018145374A1 - 电磁加热设备、电磁加热系统及其加热控制方法和装置 - Google Patents

电磁加热设备、电磁加热系统及其加热控制方法和装置 Download PDF

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Publication number
WO2018145374A1
WO2018145374A1 PCT/CN2017/086211 CN2017086211W WO2018145374A1 WO 2018145374 A1 WO2018145374 A1 WO 2018145374A1 CN 2017086211 W CN2017086211 W CN 2017086211W WO 2018145374 A1 WO2018145374 A1 WO 2018145374A1
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Prior art keywords
heating system
electromagnetic heating
power
heating
phase
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PCT/CN2017/086211
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English (en)
French (fr)
Inventor
江德勇
王云峰
杜放
卢伟杰
李睿
钟石刚
曾露添
张帆
雷俊
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Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
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Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
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Publication of WO2018145374A1 publication Critical patent/WO2018145374A1/zh
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power
    • H05B6/062—Control, e.g. of temperature, of power for cooking plates or the like

Definitions

  • the invention relates to the technical field of household appliances, in particular to a heating control method of an electromagnetic heating system, a heating control device of an electromagnetic heating system, an electromagnetic heating system and an electromagnetic heating device.
  • the electromagnetic resonance circuit of a single IGBT generally adopts a parallel resonance mode, and sets a resonance parameter under the premise of realizing high-power operation, as shown in FIG. 1 , when heating with high power, due to resonance parameter matching, IGBT conduction
  • the leading voltage of the current time is very small, and the pulse current of the IGBT is also very small.
  • the lead voltage of the IGBT is very high, resulting in a very large pulse current of the IGBT, and it is particularly easy to exceed the use limit of the IGBT and damage the IGBT.
  • the related art In order to achieve low power, the related art generally adopts a duty ratio method as shown in FIG. 3 to perform intermittent heating, for example, by stopping 5 seconds by heating for 5 seconds, achieving a low power of 5/10.
  • the related art has a problem if Intermittent heating cycle is long, it will affect the cooking function, such as easy to overflow when porridge, reduce the user's cooking experience, if the intermittent heating cycle is short, it will lead to hard turn-on of the IGBT, which leads to very large pulse current of the IGBT, and noise serious.
  • a first object of the present invention is to provide a heating control method for an electromagnetic heating system capable of suppressing a pulse current of a power switching tube and achieving low power heating of a millisecond duty ratio.
  • a second object of the present invention is to provide a heating control device for an electromagnetic heating system.
  • a third object of the present invention is to provide an electromagnetic heating system.
  • a fourth object of the present invention is to provide an electromagnetic heating apparatus.
  • a first aspect of the present invention provides a heating control method for an electromagnetic heating system, comprising the steps of: acquiring a target heating power of the electromagnetic heating system; and determining whether the target heating power is less than a preset power.
  • the electromagnetic heating system controlling the electromagnetic heating system to sequentially enter a discharging phase, a heating phase, and a stopping phase in each control cycle, wherein a plurality of firsts are provided in the discharging phase Pulse signal to a power switch tube of the resonant circuit such that a current flowing through the power switch tube is less than a preset current value, and a plurality of second pulse signals are provided to the power switch tube during the heating phase,
  • the amplitude of the first pulse signal is a first driving voltage
  • the amplitude of the second pulse signal is a second driving voltage
  • the first driving voltage is less than the second driving voltage.
  • the resonant circuit of the control electromagnetic heating system sequentially enters the discharging phase, the heating phase, and the stopping phase in each control cycle, wherein Providing a plurality of first pulse signals to the power switching tube of the resonant circuit during the discharging phase such that the current flowing through the power switching tube is less than a preset current value, and providing a plurality of second pulse signals to the power switching tube during the heating phase
  • the amplitude of the first pulse signal is a first driving voltage
  • the amplitude of the second pulse signal is a second driving voltage
  • the first driving voltage is less than the second driving voltage.
  • the heating control method of the electromagnetic heating system according to the above embodiment of the present invention may further have the following additional technical features:
  • the third driving voltage is continuously output to the power switch tube during the stop phase to drive the power switch tube to turn off.
  • the pulse widths of the plurality of first pulse signals are gradually increased, and the difference in pulse widths of the adjacent two first pulse signals is less than or equal to a preset width threshold.
  • the preset width threshold may range from 1.5 us to 2.5 us, and the pulse width of the first first pulse may be greater than or equal to 0.1 us and less than or equal to 10 us.
  • the electromagnetic heating system is powered by an alternating current source
  • the method further includes: obtaining a voltage zero crossing of the alternating current power source; controlling the electromagnetic heating system to enter the discharging phase according to the voltage zero crossing point.
  • the heating control method of the electromagnetic heating system further includes: controlling the electromagnetic heating system to enter the heating stage after entering a predetermined period of the discharging phase or at the voltage zero-crossing point, The discharge phase is placed within a zero-crossing voltage interval centered at the voltage zero crossing.
  • the voltage zero-crossing interval may be [-5ms, 5ms].
  • the predetermined current value is 85A.
  • the first driving voltage is greater than or equal to 5V and less than or equal to 14.5V
  • the second driving voltage is greater than or equal to 15V.
  • a second aspect of the present invention provides a heating control apparatus for an electromagnetic heating system, including: a resonant circuit including a power switching tube; a driving circuit, the driving circuit and the power switch a control terminal of the tube is connected, the driving circuit is configured to output a first driving voltage to the power switch tube to drive the power switch tube to operate in an amplified state, or output a second driving voltage to the power switch tube to drive the
  • the power switch tube operates in a saturated state, or outputs a third driving voltage to the power switch tube to drive the power switch tube to be turned off;
  • the control unit is connected to the drive circuit, and the control unit is used by the control unit Obtaining a target heating power of the electromagnetic heating system, and determining whether the target heating power is less than a preset power, and controlling the electromagnetic heating in each control period when the target heating power is less than the preset power
  • the system sequentially enters a discharge phase, a heating phase, and a stop phase, wherein the drive is controlled during the discharge phase
  • the circuit
  • the control unit controls the resonant circuit of the electromagnetic heating system to sequentially enter the discharging phase, the heating phase, and the stopping phase in each control cycle.
  • a plurality of first pulses are provided during the discharge phase Signaling to the power switch tube of the resonant circuit such that the current flowing through the power switch tube is less than a preset current value, and providing a plurality of second pulse signals to the power switch tube during the heating phase, the amplitude of the first pulse signal is a driving voltage, the amplitude of the second pulse signal is a second driving voltage, and the first driving voltage is less than the second driving voltage.
  • control unit is further configured to continuously output a third driving voltage to the power switch tube during the stopping phase to drive the power switch tube to be turned off.
  • the pulse widths of the plurality of first pulse signals are gradually increased, and the difference in pulse widths of the adjacent two first pulse signals is less than or equal to a preset width threshold.
  • the preset width threshold has a value ranging from 1.5 us to 2.5 us, and the pulse width of the first first pulse signal is greater than or equal to 0.1 us and less than or equal to 10 us.
  • the electromagnetic heating system is powered by an alternating current power source, the device further comprising: a zero crossing detecting unit, the zero crossing detecting unit is connected to the control unit, and the zero crossing detecting unit is used And acquiring the voltage zero-crossing point of the AC power source, the control unit is configured to control the electromagnetic heating system to enter the discharging phase according to the voltage zero-crossing point.
  • control unit is further configured to control the electromagnetic heating system to enter the heating phase after entering a predetermined period of the discharging phase or at the voltage zero-crossing point, so that the discharging phase It is in the zero-crossing voltage interval centered on the voltage zero-crossing point.
  • the voltage zero-crossing interval is [-5ms, 5ms].
  • the predetermined current value is 85A.
  • the first driving voltage is greater than or equal to 5V and less than or equal to 14.5V
  • the second driving voltage is greater than or equal to 15V.
  • an embodiment of the third aspect of the present invention provides an electromagnetic heating system including the control device of the electromagnetic heating system.
  • the pulse current of the power switch tube can be suppressed by the pre-discharge mode, thereby achieving low-power heating of the millisecond pole duty ratio, thereby improving the user experience.
  • an embodiment of the fourth aspect of the present invention provides an electromagnetic heating apparatus including the electromagnetic heating system.
  • the pulse current of the power switch tube can be suppressed by the pre-discharge mode, thereby achieving low-power heating of the millisecond pole duty ratio and improving the user experience.
  • the electromagnetic heating device may be an induction cooker, an electromagnetic cooker, an electromagnetic rice cooker or an electromagnetic pressure cooker.
  • FIG. 1 is a schematic diagram showing driving waveforms of an IGBT when an electromagnetic heating system is heated at a high power in the related art
  • FIG. 2 is a schematic diagram showing driving waveforms of an IGBT when an electromagnetic heating system is heated at a low power in the related art
  • FIG. 3 is a diagram showing a duty cycle waveform when the electromagnetic heating system is heated in a duty ratio manner in the related art
  • FIG. 4 is a flow chart of a heating control method of an electromagnetic heating system according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram showing a relationship between driving voltage and current of an IGBT tube according to an embodiment of the present invention
  • FIG. 6 is a schematic diagram showing the principle of a heating control method of an electromagnetic heating system according to an embodiment of the present invention.
  • Figure 7 is a development waveform diagram of the discharge phase D1, the heating phase D2, and the stop phase D3 of Figure 6;
  • FIG. 8 is a control schematic diagram of a first pulse signal and a second pulse signal in a heating control method of an electromagnetic heating system according to an embodiment of the present invention
  • FIG. 9 is a block schematic diagram of a heating control device of an electromagnetic heating system in accordance with an embodiment of the present invention.
  • FIG. 10 is a block schematic diagram of a heating control device of an electromagnetic heating system in accordance with one embodiment of the present invention.
  • FIG. 11 is a circuit schematic diagram of an electromagnetic heating system in accordance with one embodiment of the present invention.
  • Figure 12 is a block schematic diagram of an electromagnetic heating system in accordance with an embodiment of the present invention.
  • FIG. 4 is a flow chart of a heating control method of an electromagnetic heating system according to an embodiment of the present invention. As shown in FIG. 4, the heating control method includes the following steps:
  • the target heating power W1 is the heating power that the electromagnetic heating system needs to achieve under different cooking parameters.
  • the porridge mode can be selected on the control panel of the electromagnetic heating system, and the electromagnetic heating system enters the porridge mode.
  • the electromagnetic heating system can perform low-power heating with the heating power of 800W.
  • the corresponding target heating power is 800W.
  • the preset power W2 may be a power value calibrated according to the actual situation. When the target heating power W1 is less than the preset power W2, it is determined that the electromagnetic heating system is low power heating, and the target heating power W1 is greater than the preset power W2. It is judged that the electromagnetic heating system is heated at a high power.
  • the preset power W2 may be 1400 W, thereby reducing the noise caused by frequent starts.
  • the control electromagnetic heating system sequentially enters a discharge phase, a heating phase, and a stop phase, wherein a plurality of first pulse signals are supplied to the resonance circuit in the discharge phase a power switch tube, and providing a plurality of second pulse signals to the power switch tube during the heating phase so that the current flowing through the power switch tube is less than a preset current value, the first pulse signal
  • the amplitude of the number is the first driving voltage
  • the amplitude of the second pulse signal is the second driving voltage
  • the first driving voltage is less than the second driving voltage.
  • the third driving voltage is continuously outputted to the power switching tube during the stop phase to drive the power switching tube to be turned off.
  • the third driving voltage can be 0V.
  • the preset current value may be 85A.
  • the power switch tube when the first driving voltage is used to drive the power switch tube, such as the IGBT tube, the power switch tube can be operated in an amplified state; when the second driving voltage is used to drive the power switch tube, such as an IGBT tube, the power switch tube can be made. The operation is in a saturated conduction state.
  • the power switch tube when the power switch tube is operating in an amplified state, it can be seen from the relationship between the driving voltage and the current of the IGBT tube shown in FIG. 5 that the current of the IGBT tube can be limited by adjusting the driving voltage supplied to the IGBT tube, thereby Sampling the first driving voltage to drive the IGBT tube can limit the current of the IGBT tube to less than 85A, thereby effectively suppressing the pulse current.
  • the first driving voltage V1 may be greater than or equal to 5V and less than or equal to 14.5V, and the second driving voltage V2 is greater than or equal to 15V.
  • the power switch tube may be an IGBT, and the first driving voltage V1 may preferably be 9V.
  • the first driving voltage supplied to the IGBT is 9V
  • the C-pole current of the IGBT may be constant at about 22A, and the IGBT operates at the amplification. The state is such that the pulse current is well suppressed.
  • the second driving voltage V2 may preferably be 15V, and the IGBT operates in a saturated state under the driving of the second driving voltage V2.
  • the third driving voltage V3 may be 0V, and the IGBT is turned off under the driving of the third driving voltage V3.
  • each control cycle includes a discharge phase D1, a heating phase D2, and a stop phase D3, that is, in each control cycle, control
  • the resonant circuit (C2 and L2 connected in parallel in FIG. 11) sequentially enters the discharge phase D1, the heating phase D2, and the stop phase D3. More specifically, the discharge phase D1 may be first entered, and the driving circuit of the electromagnetic heating system is controlled to output a plurality of first pulse signals to the control end of the power switch tube, so that the power switch tube operates in an amplified state, so that the previous control cycle can be performed.
  • the stored energy stored in the filter capacitor ie, C1 in FIG.
  • the control driving circuit After the discharge phase D1 is completed, enter the heating In stage D2, in the heating stage D2, the control driving circuit outputs a plurality of second pulse signals to the control end of the power switch tube to operate the power switch tube in a saturated conduction state, and the electromagnetic heating system can perform normal resonance heating. Further, after the completion of the heating phase D2, the stop phase D3 is entered. In the stop phase D3, the control drive circuit outputs a third drive voltage, that is, 0 V, and the pulse signal is not output, and the power switch tube is turned off, at which time the electromagnetic heating system stops heating.
  • the duty cycle mode can be used to control the electromagnetic heating system to perform low-power heating, that is, in each control cycle, the electromagnetic heating system can be controlled to first heat t1 time and then stop heating for t2 time, and the duty ratio is t1/(t1+). T2).
  • the control period can be shortened to the millisecond pole, for example, the duty ratio is set in units of a half-wave period of the AC mains, thereby adopting a millisecond polarity duty ratio.
  • the mode control electromagnetic heating system will perform low power heating.
  • the duty ratio may refer to the ratio of the number of half waves occupied by the heating phase to the half wave number occupied by the entire control period, for example, if the control period is 4 half waves, if Heating one half wave, stopping heating three half waves, the duty ratio is 1/4, that is, the duration of the heating phase D2 in each control cycle is about one half wave period; for example, the control period is four and a half.
  • the duty ratio is 2/4, that is, the duration of the heating phase D2 in each control cycle is about two half-wave periods; for example, control When the period is 4 half-waves, if three half-waves are heated and one half-wave is stopped, the duty ratio is 3/4, that is, the duration of the heating phase D2 in each control cycle is about three half-wave periods. .
  • the pre-discharge mode that is, the electric energy stored by the discharge capacitor in the discharge phase
  • the pulse current of the power switch tube can be suppressed
  • the control period can be shortened to the millisecond pole, so that the heating effect is substantially equivalent to the continuous low power.
  • the electromagnetic heating system is powered by an alternating current power source such as an alternating current power source, and the method further comprises: obtaining a voltage zero-crossing point of the alternating current power source; and controlling the electromagnetic heating system to enter the discharging phase according to the voltage zero-crossing point.
  • an alternating current power source such as an alternating current power source
  • discharge phase can be entered near the voltage zero crossing point, and the discharge phase can be entered before the voltage zero crossing point, the voltage zero crossing point or the voltage zero crossing point.
  • the heating control method of the electromagnetic heating system further includes: when entering the discharge phase preset After the interval or at the voltage zero crossing, the electromagnetic heating system is controlled to enter the heating phase so that the discharge phase is within the zero-crossing voltage interval centered on the voltage zero-crossing point.
  • the control resonant circuit exits the discharge phase and enters the heating phase.
  • the voltage crossing point may be used to determine whether the discharge phase is completed, that is, if a voltage zero crossing is detected, the resonant circuit is controlled to exit the discharging phase and enter the heating phase.
  • the voltage zero-crossing interval is [-5ms, 5ms]. That is to say, the discharge phase can be within 5 ms before and after the voltage zero crossing.
  • the heating control method of the electromagnetic heating system further includes: controlling the electromagnetic heating system to enter the stopping phase according to the voltage zero-crossing point.
  • the entire control period is 4 half waves and the heating period is close to 2 half waves.
  • the heating control method of the electromagnetic heating system is as follows:
  • the discharge phase D1 can be entered before the first zero crossing point A1.
  • the first zero crossing point A1 can be estimated first, and then the discharge is obtained according to the estimated first zero crossing point A1 and the discharge period D1 for a preset time tf.
  • the electromagnetic heating system is controlled to enter the discharge phase D1 at the start time, that is, the control drive circuit outputs the first pulse signal having the amplitude of the first driving voltage V1 to the power switch tube, so that the power switch tube operates in the amplified state. .
  • the voltage zero-crossing point is detected in real time, and when the voltage zero-crossing point, that is, the first zero-crossing point A1, is detected, the electromagnetic heating system is controlled to enter the heating phase D2, that is, the control driving circuit output amplitude is controlled.
  • the second pulse signal of the second driving voltage V2 is connected to the control end of the power switch tube to operate the power switch tube in a saturated conduction state, and the electromagnetic heating system can perform normal resonance heating.
  • the duration of the heating phase D2 is close to two half-wave periods.
  • the voltage zero-crossing point is continuously detected in real time, and when the third zero-crossing point A3 is detected, the electromagnetic heating system is controlled to enter. Stopping phase D3, that is, controlling the driving circuit to continuously output the third driving voltage 0V to the control end of the power switch tube, the drive power switch tube is turned off, and the electromagnetic heating system stops heating.
  • the duration of the stop phase D3 is close to two half-wave periods.
  • the fifth zero-crossing point A5 can be estimated first, and then the predetermined preset time is required according to the estimated fifth zero-crossing point A5 and the discharge phase D1.
  • the start time of the discharge phase D1 in the next control cycle is obtained.
  • the pulse widths of the plurality of first pulse signals may be gradually increased, and the difference in pulse widths of the adjacent two first pulse signals is less than or equal to a preset width threshold.
  • the pulse width may refer to the duration of the high level
  • the increasing pulse width of the plurality of first pulse signals means that the overall trend of the pulse widths of the plurality of first pulse signals is increasing, and the incremental manner may be The method includes, but is not limited to, increasing sequentially according to the same preset increment, or sequentially increasing according to different preset increments, or continuously increasing the plurality of pulse widths during the increasing process.
  • the driving circuit outputs M first pulse signals to the power switch tube to release the power stored in the filter capacitor of the D3 in the previous stop phase, wherein the M pulse signals
  • the pulse widths can be Y1, Y2, ..., Ym-2, Ym-1, Ym, respectively.
  • the pulse widths of the M pulse signals can satisfy the following relationship: Ym ⁇ Ym-1 ⁇ Ym -2,..., ⁇ Y2 ⁇ Y1. More specifically, the pulse width difference of each two adjacent first pulse signals may be equal, that is, sequentially increased by the same preset increment; or the difference between the pulse widths of two adjacent first pulse signals is Zero, so that a continuous number of pulse widths remain unchanged.
  • the preset width threshold may have a value ranging from 1.5 us to 2.5 us, preferably 2 us.
  • the pulse width of the first first pulse signal, that is, Y1 may be greater than or equal to 0.1us And less than or equal to 10us.
  • the pulse width of any one of the first pulse signals is smaller than the pulse width of each of the second pulse signals.
  • the pulse widths of the plurality of first pulse signals provided in the discharge phase are each smaller than the minimum pulse width of the pulse widths of the plurality of second pulse signals supplied in the heating phase.
  • the pulse widths of the plurality of second pulse signals are both Yn, then Ym, Ym-1, Ym-2, ..., Y2, Y1 are all smaller than Yn.
  • the power switch tube when the target heating power W1 is greater than or equal to the preset power W2, the power switch tube can be driven by a single second driving voltage, and the electromagnetic heating system can perform continuous high power heating.
  • the driving circuit of the electromagnetic heating system may include a driving module and a transformer module, and the driving module is configured to output a driving pulse signal to the power switching tube to drive the power switch tube to be turned on or off.
  • the transformer module is used to adjust the driving voltage of the driving pulse signal.
  • the control unit of the electromagnetic heating system has a first control output end and a second control output end, the first control output end is connected to the drive module, the second control output end is connected to the transformer module, and the control unit is output through the first control output end.
  • the transformer module When the first control signal is, for example, a PPG signal and the second control signal is outputted through the second control output, for example, a high level signal, the transformer module performs a voltage transformation to adjust the driving voltage of the driving pulse signal to the first driving voltage V1, and the driving circuit Providing a first pulse signal having an amplitude of the first driving voltage V1 to the power switching tube; the control unit outputs a first control signal, such as a PPG signal, through the first control output, and outputs a third control signal through the second control output, for example When the signal is low level, the transformer module does not perform voltage transformation, the driving voltage of the driving pulse signal is maintained at the second driving voltage V2, and the driving circuit can provide the second pulse signal with the amplitude of the second driving voltage V2 to the power switching tube.
  • a first control signal such as a PPG signal
  • the transformer module does not perform voltage transformation, the driving voltage of the driving pulse signal is maintained at the second driving voltage V2, and the driving circuit can provide the second pulse signal with the ampli
  • the heating control method of the electromagnetic heating system first obtains the target heating power of the electromagnetic heating system, and then determines whether the target heating power is less than the preset power, and if the target heating power is less than the preset power, Then, in each control cycle, the resonant circuit controlling the electromagnetic heating system sequentially enters a discharge phase, a heating phase, and a stop phase, wherein a plurality of first pulse signals are supplied to the power switch tube of the resonant circuit during the discharge phase to cause the flow through The current of the power switch tube is less than the pre- Setting a current value, and providing a plurality of second pulse signals to the power switch tube during the heating phase, the amplitude of the first pulse signal is a first driving voltage, the amplitude of the second pulse signal is a second driving voltage, and the first driving The voltage is less than the second drive voltage.
  • the pre-discharge method can suppress the pulse current of the power switching tube, thereby achieving low-power heating with a mill
  • FIG. 9 is a block schematic diagram of a heating control device of an electromagnetic heating system in accordance with an embodiment of the present invention.
  • the heating control device of the electromagnetic heating system includes a drive circuit 10, a resonance circuit 20, and a control unit 30.
  • the resonant circuit 20 includes a power switch tube drive 40. As shown in FIG. 11, the rate switch tube drive 40 can be an IGBT tube.
  • the resonant circuit 20 further includes a resonant capacitor C2 and a heating coil L2.
  • the resonant capacitor C2 and the heating coil L2 can be connected in parallel. Connected, parallel resonant capacitor C2 and one end of heating coil L2 are connected to filter inductor L1, also connected to one end of filter capacitor C1, the other end of filter capacitor C1 is grounded, parallel resonant capacitor C2 and the other end of heating coil L2 and IGBT
  • the C pole of the tube is connected, and the E pole of the IGBT tube is grounded.
  • the driving circuit 10 is connected to the control terminal of the power switch tube 40, for example, the G pole of the IGBT, and the driving circuit 10 is configured to output the first driving voltage to the power switch tube 40 to drive the power switch tube 40 to operate in an amplified state, or output a second driving voltage.
  • the power switch tube 40 is operated to drive the power switch tube 40 to operate in a saturated state, or the third drive voltage is output to the power switch tube 40 to drive the power switch tube 40 to be turned off.
  • the control unit 30 is connected to the driving circuit 10, and the control unit 30 is configured to acquire the target heating power of the electromagnetic heating system, and determine whether the target heating power is less than the preset power, and when the target heating power is less than the preset power, in each control cycle.
  • the control electromagnetic heating system sequentially enters a discharge phase, a heating phase and a stop phase, wherein the control drive circuit 10 supplies a plurality of first pulse signals to the power switch tube 40 in the discharge phase such that the current flowing through the power switch tube 40 is less than a preset current And driving the driving circuit 10 to provide a plurality of second pulse signals to the power switch tube 40 during the heating phase, the amplitude of the first pulse signal being the first driving voltage, the amplitude of the second pulse signal being the second driving voltage, and The first driving voltage is less than the second driving voltage.
  • control unit 30 is further configured to continue during the stop phase.
  • the third driving voltage is output to the power switch tube 40 to drive the power switch tube 40 to be turned off.
  • the target heating power W1 is the heating power that the electromagnetic heating system needs to achieve under different cooking parameters.
  • the porridge mode can be selected on the control panel of the electromagnetic heating system, and the electromagnetic heating system enters the porridge mode.
  • the electromagnetic heating system can perform low-power heating with the heating power of 800W.
  • the corresponding target heating power is 800W.
  • the preset power W2 may be a power value calibrated according to the actual situation. When the target heating power W1 is less than the preset power W2, it is determined that the electromagnetic heating system is low power heating, and the target heating power W1 is greater than the preset power W2. It is judged that the electromagnetic heating system is heated at a high power.
  • the preset power W2 may be 1400 W, thereby reducing the noise caused by frequent starts.
  • the preset current value may be 85A.
  • the power switch tube 40 when the first driving voltage is used to drive the power switch tube 40, for example, the IGBT tube, the power switch tube 40 can be operated in an amplified state; when the second driving voltage is used to drive the power switch tube, such as an IGBT tube, the power can be made.
  • the switch 40 operates in a saturated conduction state.
  • the control unit 30 can limit the current of the IGBT tube by adjusting the driving voltage supplied to the IGBT tube.
  • the C-pole current of the IGBT tube can be kept constant at about 22A, thereby sampling the first driving voltage to drive the IGBT tube, and the current of the IGBT tube can be limited to 85A or less. Thereby effectively suppressing the pulse current.
  • the first driving voltage V1 may be greater than or equal to 5V and less than or equal to 14.5V
  • the second driving voltage V2 is greater than or equal to 15V.
  • the power switch tube 40 may be an IGBT
  • the first driving voltage V1 may preferably be 9V
  • the C-pole current of the IGBT may be constant at about 22A
  • the IGBT operates at The state of amplification is amplified so that the pulse current is well suppressed.
  • the second driving voltage V2 may preferably be 15V, and the IGBT operates in a saturated state under the driving of the second driving voltage V2.
  • the third driving voltage V3 may be 0V, and the IGBT is turned off under the driving of the third driving voltage V3.
  • each control cycle includes a discharge phase D1, a heating phase D2, and a stop phase D3, that is, in each control cycle, control
  • the unit 30 controls the resonant circuit (such as C2 and L2 connected in parallel in FIG. 11) to sequentially enter the discharge phase D1, the heating phase D2, and the stop phase D3. More specifically, the discharge stage D1 may be first entered, and the control unit 30 controls the drive circuit 10 to output a plurality of first pulse signals to the control end of the power switch tube 40, so that the power switch tube 40 operates in an amplified state, so that the previous one can be The stored energy stored in the filter capacitor (ie, C1 in FIG.
  • the control unit 30 controls the driving circuit 10 to output a plurality of second pulse signals to the control end of the power switch tube 40 to operate the power switch tube 40 in the saturation guide. In the on state, the electromagnetic heating system can perform normal resonant heating. And, after the completion of the heating phase D2, the process enters the stop phase D3. In the stop phase D3, the control unit 30 controls the drive circuit 10 to output a third drive voltage, that is, 0V, does not output a pulse signal, and the power switch tube 40 is turned off. Stop heating.
  • the duty cycle mode can be used to control the electromagnetic heating system to perform low-power heating, that is, in each control cycle (t1+t2), the electromagnetic heating system can be controlled to first heat t1 time and then stop heating t2 time, and the duty ratio is t1. /(t1+t2).
  • the control period can be shortened to the millisecond pole, for example, the duty ratio is set in units of a half-wave period of the AC mains, thereby adopting a millisecond polarity duty ratio.
  • the mode control electromagnetic heating system will perform low power heating.
  • the duty ratio may refer to the ratio of the number of half waves occupied by the heating phase to the half wave number occupied by the entire control period, for example, if the control period is 4 half waves, if When heating one half wave and stopping heating three half waves, the duty ratio is 1/4. For example, if the control period is 4 half waves, if two half waves are heated and the heating is stopped for two half waves, The space ratio is 2/4; if the control period is 4 half waves, if three half waves are heated and one half wave is stopped, the duty ratio is 3/4.
  • the pre-discharge mode that is, the electrical energy stored by the discharge capacitor is discharged during the discharge phase
  • the pulse current of the power switch tube can be suppressed, and the control period can be shortened to the millisecond pole, so that the heating effect base This is equivalent to continuous low power.
  • the electromagnetic heating system can be powered by an alternating current power source.
  • the apparatus further includes: a zero crossing detecting unit 50, and the zero crossing detecting unit 50 is connected to the control unit 30, and the zero crossing detecting unit 50
  • the control unit 30 is configured to control the electromagnetic heating system to enter the discharge phase according to the voltage zero-crossing point.
  • control unit 30 can control the resonant circuit 20 to enter the discharge phase near the voltage zero-crossing point, that is, to enter the discharge phase before the voltage zero-crossing point, the voltage zero-crossing point, or the voltage zero-crossing point.
  • control unit 30 is further configured to control the electromagnetic heating system to enter the heating phase after entering the discharge phase for a preset time or at the voltage zero-crossing point, so that the discharge phase is at zero crossing centered on the voltage zero-crossing point.
  • whether the discharge phase is completed can be judged based on the time, that is, if the duration of the discharge phase reaches the preset time, the control unit 30 controls the resonant circuit to exit the discharge phase and enter the heating phase.
  • the control unit 30 controls the resonance circuit to exit the discharge phase and enter the heating phase.
  • the voltage zero-crossing interval is [-5ms, 5ms]. That is to say, the discharge phase can be within 5 ms before and after the voltage zero crossing.
  • control unit 30 may also control the electromagnetic heating system to enter a stop phase based on the voltage zero crossings.
  • control unit 30 can perform heating control as follows:
  • the control unit 30 can control the electromagnetic heating system to enter the discharge phase D1 before the first zero-crossing point A1.
  • the first zero-crossing point A1 can be estimated first, and then the first zero-crossing point A1 and the discharge phase D1 should be continued according to the estimation.
  • the preset time acquires the start time of the discharge phase D1.
  • the control unit 30 controls the electromagnetic heating system to enter the discharge phase D1, that is, the control drive circuit 10 outputs the first pulse signal having the amplitude of the first drive voltage V1 to the power switch tube. In order to make the power switch tube 40 work Big state.
  • the control unit 30 detects the voltage zero-crossing point in real time through the zero-crossing detecting unit 50 in the process of controlling the driving of the first pulse signal, and controls the electromagnetic heating system to enter when the voltage zero-crossing point, that is, the first zero-crossing point A1 is detected.
  • the heating stage D2 that is, the control unit 30 controls the driving circuit 10 to output the second pulse signal having the second driving voltage V2 to the control end of the power switching tube 40, so that the power switching tube 40 operates in the saturated conducting state.
  • the electromagnetic heating system performs normal resonant heating.
  • the duration of the heating phase D2 is close to two half-wave periods, and the control unit 30 continues in the process of controlling the driving circuit 10 to output the second pulse signal, and the voltage zero-crossing point is detected in real time by the zero-crossing detecting unit 50, and the third is detected.
  • the electromagnetic heating system is controlled to enter the stop phase D3, that is, the control unit 30 controls the driving circuit 10 to continuously output the third driving voltage, that is, 0V to the control end of the power switch tube 40, to drive the power switch tube 40 to be turned off, and the electromagnetic The heating system stops heating.
  • the duration of the stop phase D3 is close to two half-wave periods.
  • the control unit 30 can first estimate the fifth zero-crossing point A5, and then continue according to the estimated fifth zero-crossing point A5 and the discharge phase D1.
  • the preset time acquires the start time of the discharge phase D1 in the next control cycle.
  • the pulse widths of the plurality of first pulse signals are gradually increased, and the difference in pulse widths of the adjacent two first pulse signals is less than or equal to a preset width threshold.
  • the pulse width may refer to the duration of the high level
  • the increasing pulse width of the plurality of first pulse signals means that the overall trend of the pulse widths of the plurality of first pulse signals is increasing, and the incremental manner may be The method includes, but is not limited to, increasing sequentially according to the same preset increment, or sequentially increasing according to different preset increments, or continuously increasing the plurality of pulse widths during the increasing process.
  • the driving circuit outputs M first pulse signals to the power switch tube to release the power stored in the filter capacitor of the D3 in the previous stop phase, wherein the M pulse signals
  • the pulse widths can be Y1, Y2, ..., Ym-2, Ym-1, Ym, respectively.
  • the pulse widths of the M pulse signals can satisfy the following relationship: Ym ⁇ Ym-1 ⁇ Ym-2, ..., ⁇ Y2 ⁇ Y1. More specifically, the pulse width difference of each two adjacent first pulse signals may be equal, that is, sequentially increased by the same preset increment; or the difference between the pulse widths of two adjacent first pulse signals is Zero, so that a continuous number of pulse widths remain unchanged.
  • the preset width threshold may range from 1.5 us to 2.5 us, preferably 2 us, and the pulse width of the first first pulse signal, that is, Y1 may be greater than or equal to 0.1 us. Less than or equal to 10us.
  • the pulse width of any one of the first pulse signals is smaller than the pulse width of each of the second pulse signals.
  • the pulse widths of the plurality of first pulse signals provided in the discharge phase are each smaller than the minimum pulse width of the pulse widths of the plurality of second pulse signals supplied in the heating phase.
  • the pulse widths of the plurality of second pulse signals are both Yn, then Ym, Ym-1, Ym-2, ..., Y2, Y1 are all smaller than Yn.
  • the control unit 30 can drive the power switch tube 40 with a single second driving voltage, and the electromagnetic heating system can perform continuous high power. heating.
  • the driving circuit 10 of the electromagnetic heating system may include a driving module 11 and a transformer module 12 for outputting a driving pulse signal to the power switching tube 30 to drive the power switch.
  • the tube 30 is turned on or off, and the transformer module 12 is used to adjust the driving voltage of the driving pulse signal.
  • the control unit 30 of the electromagnetic heating system has a first control output PPG and a second control output EN, the first control output PPG is connected to the drive module 11, and the second control output EN is connected to the transformer module 12, the control unit 30
  • a first control signal such as a PPG signal
  • a second control signal such as a high level signal
  • the voltage module 12 performs voltage transformation to adjust the driving voltage of the driving pulse signal to the first driving voltage V1
  • the driving circuit 10 can provide the first pulse signal having the amplitude of the first driving voltage V1 to the power switch tube 40
  • the control unit 30 is When the first control output terminal PPG outputs a first control signal, such as a PPG signal, and outputs a third control signal, such as a low level signal, through the second control output terminal EN, the transformer module 12 does not perform voltage transformation, and drives the driving voltage of the pulse signal. Maintaining the second driving voltage V2, the driving circuit 10 can provide a second pulse signal having an amplitude
  • the control unit controls the resonant circuit of the electromagnetic heating system to sequentially enter the discharging phase in each control cycle.
  • a heating phase and a stopping phase wherein a plurality of first pulse signals are supplied to the power switching tube of the resonant circuit during the discharging phase such that a current flowing through the power switching tube is less than a preset current value, and a plurality of second pulses are provided in the heating phase
  • the signal is sent to the power switch tube.
  • the amplitude of the first pulse signal is the first driving voltage
  • the amplitude of the second pulse signal is the second driving voltage
  • the first driving voltage is less than the second driving voltage.
  • an embodiment of the present invention also provides an electromagnetic heating system.
  • FIG. 12 is a block schematic diagram of an electromagnetic heating system in accordance with an embodiment of the present invention. As shown in Fig. 12, the electromagnetic heating system 60 includes the heating control device 70 of the electromagnetic heating system of the above embodiment.
  • the electromagnetic heating system 60 is suitable for use in an induction cooker, an electromagnetic cooktop, an electromagnetic rice cooker or an electromagnetic pressure cooker or the like.
  • the pulse current of the power switch tube can be suppressed by the pre-discharge mode, thereby achieving low-power heating of the millisecond pole duty ratio, thereby improving the user experience.
  • an embodiment of the present invention also provides an electromagnetic heating apparatus comprising the electromagnetic heating system of the above embodiment.
  • the electromagnetic heating device may be an induction cooker, an electromagnetic cooker, an electromagnetic rice cooker or an electromagnetic pressure cooker or the like.
  • An electromagnetic heating device can suppress power by a pre-discharge method
  • the pulse current of the switch tube which in turn achieves low-power heating with a millisecond duty cycle, improves the user experience.
  • first and second are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated.
  • features defining “first” or “second” may include at least one of the features, either explicitly or implicitly.
  • the meaning of "a plurality” is at least two, such as two, three, etc., unless specifically defined otherwise.
  • the terms “installation”, “connected”, “connected”, “fixed” and the like shall be understood broadly, and may be either a fixed connection or a detachable connection, unless explicitly stated and defined otherwise. , or integrated; can be mechanical or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction of two elements, unless otherwise specified Limited.
  • the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.
  • the first feature "on” or “under” the second feature may be a direct contact of the first and second features, or the first and second features may be indirectly through an intermediate medium, unless otherwise explicitly stated and defined. contact.
  • the first feature "above”, “above” and “above” the second feature may be that the first feature is directly above or above the second feature, or merely that the first feature level is higher than the second feature.
  • the first feature “below”, “below” and “below” the second feature may be that the first feature is directly below or obliquely below the second feature, or merely that the first feature level is less than the second feature.
  • each functional unit in each embodiment of the present invention may be integrated into one processing module, or each unit may exist physically separately, or two or more units may be integrated into one module.
  • the above integrated modules can be implemented in the form of hardware or in the form of software functional modules.
  • the integrated modules, if implemented in the form of software functional modules and sold or used as stand-alone products, may also be stored in a computer readable storage medium.
  • the above mentioned storage medium may be a read only memory, a magnetic disk or an optical disk or the like.

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Abstract

本发明公开了一种电磁加热设备、电磁加热系统及其加热控制方法和装置，所述方法包括以下步骤：获取所述电磁加热系统的目标加热功率；判断所述目标加热功率是否小于预设功率；如果所述目标加热功率小于所述预设功率，则在每个控制周期，控制所述电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在所述放电阶段提供多个第一脉冲信号至谐振电路的功率开关管，并在所述加热阶段提供多个第二脉冲信号至所述功率开关管，所述第一脉冲信号的幅值为第一驱动电压，所述第二脉冲信号的幅值为第二驱动电压，且所述第一驱动电压小于所述第二驱动电压。由此，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热。

Description

电磁加热设备、电磁加热系统及其加热控制方法和装置 技术领域
本发明涉及家用电器技术领域，特别涉及一种电磁加热系统的加热控制方法、一种电磁加热系统的加热控制装置、一种电磁加热系统以及一种电磁加热设备。
背景技术
相关技术中，单IGBT的电磁谐振电路通常采用并联谐振方式，并在实现大功率运行的前提下设置谐振参数，如图1所示，当以高功率进行加热时，因谐振参数匹配，IGBT导通时的超前电压非常小，IGBT的脉冲电流也非常小。然而，如图2所示，在采用低功率加热时，IGBT的超前电压非常高，导致IGBT的脉冲电流非常大，特别容易超出IGBT的使用限值，损坏IGBT。
为了实现低功率，相关技术通常采用如图3所示的占空比方式进行间断加热，例如通过加热5s停止5s的方式，实现5/10的低功率，但是，相关技术存在的问题是，如果间断加热周期较长，会影响烹饪功能，例如在煮粥的时容易溢出，降低用户的烹饪体验，如果间断加热周期较短，会导致IGBT硬开通，进而导致IGBT的脉冲电流非常大，而且噪音严重。
发明内容
本发明旨在至少在一定程度上解决相关技术中的技术问题之一。为此，本发明的第一个目的在于提出一种电磁加热系统的加热控制方法，能够抑制功率开关管的脉冲电流，可实现毫秒级占空比的低功率加热。
本发明的第二个目的在于提出一种电磁加热系统的加热控制装置。本发明的第三个目的在于提出一种电磁加热系统。本发明的第四个目的在于提出一种电磁加热设备。
为达到上述目的，本发明第一方面实施例提出了一种电磁加热系统的加热控制方法，包括以下步骤：获取所述电磁加热系统的目标加热功率；判断所述目标加热功率是否小于预设功率；如果所述目标加热功率小于所述预设功率，则在每个控制周期，控制所述电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在所述放电阶段提供多个第一脉冲信号至所述谐振电路的功率开关管以使流过所述功率开关管的电流小于预设电流值，并在所述加热阶段提供多个第二脉冲信号至所述功率开关管，所述第一脉冲信号的幅值为第一驱动电压，所述第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。
根据本发明实施例提出的电磁加热系统的加热控制方法，当目标加热功率小于预设功率时，在每个控制周期，控制电磁加热系统的谐振电路依次进入放电阶段、加热阶段和停止阶段，其中，在放电阶段提供多个第一脉冲信号至谐振电路的功率开关管以使流过所述功率开关管的电流小于预设电流值，并在加热阶段提供多个第二脉冲信号至功率开关管，第一脉冲信号的幅值为第一驱动电压，第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。由此，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
另外，根据本发明上述实施例的电磁加热系统的加热控制方法还可以具有如下附加的技术特征：
根据本发明的一个实施例，在所述停止阶段持续输出第三驱动电压至所述功率开关管，以驱动所述功率开关管关断。
根据本发明的一个实施例，所述多个第一脉冲信号的脉冲宽度逐渐增加，且相邻两个第一脉冲信号的脉冲宽度的差值小于等于预设宽度阈值。其中，所述预设宽度阈值的取值范围可为1.5us-2.5us，第一个第一脉冲信号的脉冲宽度可大于等于0.1us且小于等于10us。
根据本发明的一个实施例，通过交流电源为所述电磁加热系统供电，所述 方法还包括：获取所述交流电源的电压过零点；根据所述电压过零点控制所述电磁加热系统进入所述放电阶段。
根据本发明的一个实施例，所述的电磁加热系统的加热控制方法还包括：在进入所述放电阶段预设时间后或者在所述电压过零点控制所述电磁加热系统进入所述加热阶段，以使所述放电阶段处于以所述电压过零点为中心构造的过零电压区间内。其中，所述电压过零区间可为[-5ms，5ms]。
根据本发明的一个实施例，所述预设电流值为85A。
根据本发明的一个实施例，所述第一驱动电压大于等于5V且小于等于14.5V，所述第二驱动电压大于等于15V。
为达到上述目的，本发明第二方面实施例提出了一种电磁加热系统的加热控制装置，包括：谐振电路，所述谐振电路包括功率开关管；驱动电路，所述驱动电路与所述功率开关管的控制端相连，所述驱动电路用于输出第一驱动电压至所述功率开关管以驱动所述功率开关管工作在放大状态，或者输出第二驱动电压至所述功率开关管以驱动所述功率开关管工作在饱和状态，或者输出第三驱动电压至所述功率开关管以驱动所述功率开关管关断；控制单元，所述控制单元与所述驱动电路相连，所述控制单元用于获取所述电磁加热系统的目标加热功率，并判断所述目标加热功率是否小于预设功率，以及在所述目标加热功率小于所述预设功率时，在每个控制周期控制所述电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在所述放电阶段控制所述驱动电路提供多个第一脉冲信号至所述功率开关管以使流过所述功率开关管的电流小于预设电流值，并在所述加热阶段控制所述驱动电路提供多个第二脉冲信号至所述功率开关管，所述第一脉冲信号的幅值为所述第一驱动电压，所述第二脉冲信号的幅值为所述第二驱动电压，且所述第一驱动电压小于所述第二驱动电压。
根据本发明实施例提出的电磁加热系统的加热控制装置，当目标加热功率小于预设功率时，在每个控制周期，控制单元控制电磁加热系统的谐振电路依次进入放电阶段、加热阶段和停止阶段，其中，在放电阶段提供多个第一脉冲 信号至谐振电路的功率开关管以使流过所述功率开关管的电流小于预设电流值，并在加热阶段提供多个第二脉冲信号至功率开关管，第一脉冲信号的幅值为第一驱动电压，第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。由此，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
根据本发明的一个实施例，所述控制单元还用于在所述停止阶段持续输出第三驱动电压至所述功率开关管，以驱动所述功率开关管关断。
根据本发明的一个实施例，所述多个第一脉冲信号的脉冲宽度逐渐增加，且相邻两个第一脉冲信号的脉冲宽度的差值小于等于预设宽度阈值。其中，所述预设宽度阈值的取值范围为1.5us-2.5us，第一个第一脉冲信号的脉冲宽度大于等于0.1us且小于等于10us。
根据本发明的一个实施例，通过交流电源为所述电磁加热系统供电，所述装置还包括：过零检测单元，所述过零检测单元与所述控制单元相连，所述过零检测单元用于获取所述交流电源的电压过零点，所述控制单元用于根据所述电压过零点控制所述电磁加热系统进入所述放电阶段。
根据本发明的一个实施例，所述控制单元还用于在进入所述放电阶段预设时间后或者在所述电压过零点控制所述电磁加热系统进入所述加热阶段，以使所述放电阶段处于以所述电压过零点为中心构造的过零电压区间内。其中，所述电压过零区间为[-5ms，5ms]。
根据本发明的一个实施例，所述预设电流值为85A。
根据本发明的一个实施例，所述第一驱动电压大于等于5V且小于等于14.5V，所述第二驱动电压大于等于15V。
为达到上述目的，本发明第三方面实施例提出了一种电磁加热系统，包括所述的电磁加热系统的控制装置。
根据本发明实施例提出的电磁加热系统，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
为达到上述目的，本发明第四方面实施例提出了一种电磁加热设备，包括所述的电磁加热系统。
根据本发明实施例提出的电磁加热设备，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
根据本发明的一个实施例，所述电磁加热设备可为电磁炉、电磁灶、电磁电饭煲或电磁压力锅。
附图说明
图1是相关技术中电磁加热系统以高功率进行加热时IGBT的驱动波形示意图；
图2是相关技术中电磁加热系统以低功率进行加热时IGBT的驱动波形示意图；
图3是相关技术中电磁加热系统以占空比方式进行加热时的占空比波形图；
图4是根据本发明实施例的电磁加热系统的加热控制方法的流程图；
图5是根据本发明一个具体实施例的IGBT管的驱动电压与电流之间的关系曲线示意图；
图6是根据本发明一个实施例的电磁加热系统的加热控制方法的原理示意图；
图7是图6中放电阶段D1、加热阶段D2和停止阶段D3的驱动波形展开图；
图8是根据本发明一个实施例的电磁加热系统的加热控制方法中第一脉冲信号和第二脉冲信号的控制原理图；
图9是根据本发明实施例的电磁加热系统的加热控制装置的方框示意图；
图10是根据本发明一个实施例的电磁加热系统的加热控制装置的方框示意图；
图11是根据本发明一个实施例的电磁加热系统的电路原理图；以及
图12是根据本发明实施例的电磁加热系统的方框示意图。
具体实施方式
下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本发明，而不能理解为对本发明的限制。
下面参照附图来描述根据本发明实施例提出的电磁加热系统的加热控制方法、电磁加热系统的加热控制装置、电磁加热系统和电磁加热设备。
图4是根据本发明实施例的电磁加热系统的加热控制方法的流程图。如图4所示，该加热控制方法包括以下步骤：
S1：获取电磁加热系统的目标加热功率W1。
其中，目标加热功率W1是电磁加热系统在不同烹饪参数下所需达到的加热功率。例如，用户想要煮小米粥时，可在电磁加热系统的控制面板上选择煮粥模式，电磁加热系统进入煮粥模式，在煮粥模式下电磁加热系统可以800W的加热功率进行低功率加热，此时对应的目标加热功率为800W。
S2：判断目标加热功率W1是否小于预设功率W2。
其中，预设功率W2可为根据实际情况标定的一个功率值，当目标加热功率W1小于预设功率W2时，判断电磁加热系统为低功率加热，而目标加热功率W1大于预设功率W2时，判断电磁加热系统为高功率加热。
根据本发明的一个具体实施例，预设功率W2可为1400W，从而降低频繁启动带来的噪音。
S3：如果目标加热功率W1小于预设功率W2，则在每个控制周期，控制电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在放电阶段提供多个第一脉冲信号至谐振电路的功率开关管，并在加热阶段提供多个第二脉冲信号至功率开关管以使流过功率开关管的电流小于预设电流值，第一脉冲信 号的幅值为第一驱动电压，第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。
进一步地，根据本发明的一个实施例，在停止阶段持续输出第三驱动电压至功率开关管，以驱动功率开关管关断。其中，第三驱动电压可为0V。
根据本发明的一个实施例，预设电流值可为85A。
需要说明的是，在采用第一驱动电压驱动功率开关管例如IGBT管时，可使功率开关管工作在放大状态；在采用第二驱动电压驱动功率开关管例如IGBT管时，可使功率开关管工作在饱和导通状态。其中，在功率开关管工作在放大状态时，从图5所示的IGBT管的驱动电压与电流之间的关系可知，通过调整提供至IGBT管的驱动电压可限制IGBT管的电流，由此，采样第一驱动电压驱动IGBT管，可将IGBT管的电流限制在85A以下，从而有效抑制脉冲电流。
根据本发明的一个具体实施例，第一驱动电压V1可大于等于5V且小于等于14.5V，第二驱动电压V2大于等于15V。更具体地，功率开关管可为IGBT，第一驱动电压V1可优选为9V，当提供至IGBT的第一驱动电压为9V时，IGBT的C极电流可恒定为22A左右，并且IGBT工作在放大状态，从而很好的抑制了脉冲电流。第二驱动电压V2可优选为15V，在第二驱动电压V2的驱动下，IGBT工作在饱和状态。第三驱动电压V3可为0V，在第三驱动电压V3的驱动下，IGBT关断。
具体来说，当目标加热功率W1小于预设功率W2时，如图6-7所示，每个控制周期包括放电阶段D1、加热阶段D2和停止阶段D3，即在每个控制周期内，控制谐振电路(如图11中并联的C2和L2)依次进入放电阶段D1、加热阶段D2和停止阶段D3。更具体地，可先进入放电阶段D1，控制电磁加热系统的驱动电路输出多个第一脉冲信号至功率开关管的控制端，以使功率开关管工作在放大状态，从而可将前一个控制周期中停止阶段期间滤波电容(即图11中的C1)存储的电能释放，使得进入加热阶段D2时功率开关管的集电极电压基本为0V，降低功率开关管的脉冲电流。在放电阶段D1完成后再进入加热 阶段D2，在加热阶段D2，控制驱动电路输出多个第二脉冲信号至功率开关管的控制端，以使功率开关管工作在饱和导通状态，此时电磁加热系统可进行正常的谐振加热。并且，在加热阶段D2完成后进入停止阶段D3，在停止阶段D3，控制驱动电路输出第三驱动电压即0V，不输出脉冲信号，功率开关管关断，此时电磁加热系统停止加热。
并且，可采用占空比方式控制电磁加热系统将进行低功率加热，即在每个控制周期，可控制电磁加热系统先加热t1时间再停止加热t2时间，占空比即为t1/(t1+t2)。具体地，如图6所示，在本发明的一个实施例中，可将控制周期缩短至毫秒极，例如以交流市电的半波周期为单位设置占空比，从而采用毫秒极占空比方式控制电磁加热系统将进行低功率加热，此时占空比可指加热阶段所占的半波数量与整个控制周期所占的半波数之比，例如，控制周期为4个半波时，如果加热1个半波，停止加热3个半波，则占空比为1/4，即每个控制周期中加热阶段D2的持续时间大约为一个半波周期；又如，控制周期为4个半波时，如果加热2个半波，停止加热2个半波，则占空比为2/4，即每个控制周期中加热阶段D2的持续时间大约为两个半波周期；再如，控制周期为4个半波时，如果加热3个半波，停止加热1个半波，则占空比为3/4，即每个控制周期中加热阶段D2的持续时间大约为三个半波周期。
由此，通过预放电方式即采用放电阶段释放滤波电容存储的电能，能够抑制功率开关管的脉冲电流，进而可将控制周期缩短至毫秒极，使得加热效果基本等同于连续低功率。
根据本发明的一个实施例，通过交流电源例如交流市电为电磁加热系统供电，方法还包括：获取交流电源的电压过零点；根据电压过零点控制电磁加热系统进入放电阶段。
需要说明的是，可在电压过零点附近进入放电阶段，即可在电压过零点之前、电压过零点或电压过零点之后进入放电阶段。
进一步地，电磁加热系统的加热控制方法还包括：在进入放电阶段预设时 间后或者在电压过零点控制电磁加热系统进入加热阶段，以使放电阶段处于以电压过零点为中心构造的过零电压区间内。
也就是说，可以时间为基准判断放电阶段是否完成，即如果放电阶段的持续时间达到预设时间，则控制谐振电路退出放电阶段，进入加热阶段。或者，也可以电压过零点判断放电阶段是否完成，即如果检测到电压过零点，则控制谐振电路退出放电阶段，进入加热阶段。
其中，电压过零区间为[-5ms，5ms]。也就是说，放电阶段可处于电压过零点前后5ms内。
另外，在本发明的一个实施例中，电磁加热系统的加热控制方法还包括：还可根据电压过零点控制电磁加热系统进入停止阶段。
具体地，结合图6的实施例，假设根据目标加热功率选择2/4占空比的低功率加热，那么整个控制周期为4个半波，加热周期接近2个半波。电磁加热系统的加热控制方法如下：
可在第一个过零点A1之前进入放电阶段D1，例如可以先估算出第一个过零点A1，然后根据估算出的第一个过零点A1和放电阶段D1需持续的预设时间tf获取放电阶段D1的开始时刻，在开始时刻控制电磁加热系统进入放电阶段D1，即控制驱动电路输出幅值为第一驱动电压V1的第一脉冲信号至功率开关管，以使功率开关管工作在放大状态。
在控制驱动电路输出第一脉冲信号的过程中，实时检测电压过零点，并在检测到电压过零点即第一个过零点A1时，控制电磁加热系统进入加热阶段D2，即控制驱动电路输出幅值为第二驱动电压V2的第二脉冲信号至功率开关管的控制端，以使功率开关管工作在饱和导通状态，此时电磁加热系统可进行正常的谐振加热。
加热阶段D2的持续时间接近两个半波周期，在控制驱动电路输出第二脉冲信号的过程中，继续实时检测电压过零点，并在检测到第三个过零点A3时，控制电磁加热系统进入停止阶段D3，即控制驱动电路持续输出第三驱动电压即 0V至功率开关管的控制端，以驱动功率开关管关断，电磁加热系统停止加热。
停止阶段D3的持续时间接近两个半波周期，在停止阶段D3，可以先估算出第五个过零点A5，然后根据估算出的第五个过零点A5和放电阶段D1需持续的预设时间获取下一个控制周期中放电阶段D1的开始时刻。
如此重复，可实现毫秒级占空比的低功率加热，使得加热效果基本等同于连续低功率。
根据本发明的一个实施例，如图7所示，多个第一脉冲信号的脉冲宽度可逐渐增加，且相邻两个第一脉冲信号的脉冲宽度的差值小于等于预设宽度阈值。
应当理解的是，脉冲宽度可指高电平的持续时间，多个第一脉冲信号的脉冲宽度逐渐增加是指多个第一脉冲信号的脉冲宽度的整体趋势是递增的，递增方式可为多种，包括但不限于，按照相同的预设增量依次增加，或者按照不同的预设增量依次增加，或者在增加过程中可使得连续的多个脉冲宽度保持不变。
具体来说，如图7所示，假设在放电阶段D1，驱动电路输出M个第一脉冲信号至功率开关管，以释放在前一个停止阶段D3滤波电容存储的电能，其中，M个脉冲信号的脉冲宽度可以分别为Y1、Y2、…、Ym-2、Ym-1、Ym，当脉冲宽度逐渐增加时，M个脉冲信号的脉冲宽度之间可满足以下关系：Ym≥Ym-1≥Ym-2，…，≥Y2≥Y1。更具体地，每两个相邻的第一脉冲信号的脉冲宽度差值可相等，即按照相同的预设增量依次增加；或者存在两个相邻第一脉冲信号的脉冲宽度的差值为零，即可使得连续的多个脉冲宽度保持不变。
另外，根据本发明的一个实施例，多个第一脉冲信号的脉冲宽度也可相同或逐渐减小。也就是说，当脉冲宽度相同时，M个脉冲信号的脉冲宽度之间可满足以下关系：Ym＝Ym-1＝Ym-2，…，＝Y2＝Y1，或者，当脉冲宽度逐渐减小时，M个脉冲信号的脉冲宽度之间可满足以下关系：Ym≤Ym-1≤Ym-2，…，≤Y2≤Y1。
其中，根据本发明的一个实施例，预设宽度阈值的取值范围可为1.5us-2.5us，优选为2us。第一个第一脉冲信号的脉冲宽度即Y1可大于等于0.1us 且小于等于10us。
需要说明的是，任一个第一脉冲信号的脉冲宽度小于每个第二脉冲信号的脉冲宽度。换言之，放电阶段提供的多个第一脉冲信号的脉冲宽度均小于加热阶段提供的多个第二脉冲信号的脉冲宽度中的最小脉冲宽度。具体地，假设多个第二脉冲信号的脉冲宽度均为Yn，那么，Ym、Ym-1、Ym-2、…、Y2、Y1均小于Yn。
另外，根据本发明的一个实施例，目标加热功率W1大于或等于预设功率W2时，可采用单一的第二驱动电压驱动功率开关管，此时电磁加热系统可进行连续高功率加热。
还需说明的是，如图8和11所示，电磁加热系统的驱动电路可包括驱动模块和变压模块，驱动模块用于输出驱动脉冲信号至功率开关管以驱动功率开关管导通或关断，变压模块用于调整驱动脉冲信号的驱动电压。电磁加热系统的控制单元具有第一控制输出端和第二控制输出端，第一控制输出端与驱动模块相连，第二控制输出端与变压模块相连，控制单元在通过第一控制输出端输出第一控制信号例如PPG信号并通过第二控制输出端输出第二控制信号例如高电平信号时，变压模块进行变压以将驱动脉冲信号的驱动电压调整为第一驱动电压V1，驱动电路可提供幅值为第一驱动电压V1的第一脉冲信号至功率开关管；控制单元在通过第一控制输出端输出第一控制信号例如PPG信号并通过第二控制输出端输出第三控制信号例如低电平信号时，变压模块不进行变压，驱动脉冲信号的驱动电压保持为第二驱动电压V2，驱动电路可提供幅值为第二驱动电压V2的第二脉冲信号至功率开关管。
综上所述，根据本发明实施例提出的电磁加热系统的加热控制方法，首先获取电磁加热系统的目标加热功率，接着判断目标加热功率是否小于预设功率，如果目标加热功率小于预设功率，则在每个控制周期，控制电磁加热系统的谐振电路依次进入放电阶段、加热阶段和停止阶段，其中，在放电阶段提供多个第一脉冲信号至谐振电路的功率开关管以使流过所述功率开关管的电流小于预 设电流值，并在加热阶段提供多个第二脉冲信号至功率开关管，第一脉冲信号的幅值为第一驱动电压，第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。由此，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
图9是根据本发明实施例的电磁加热系统的加热控制装置的方框示意图。如图9所示，电磁加热系统的加热控制装置，包括：驱动电路10、谐振电路20和控制单元30。
其中，谐振电路20包括功率开关管驱动40，如图11所示，率开关管驱动40可为IGBT管，谐振电路20还包括谐振电容C2和加热线圈L2，谐振电容C2和加热线圈L2可并联连接，并联的谐振电容C2和加热线圈L2的一端与滤波电感L1相连，还与滤波电容C1的一端相连，滤波电容C1的另一端接地，并联的谐振电容C2和加热线圈L2的另一端与IGBT管的C极相连，IGBT管的E极接地。
驱动电路10与功率开关管40的控制端例如IGBT的G极相连，驱动电路10用于输出第一驱动电压至功率开关管40以驱动功率开关管40工作在放大状态，或者输出第二驱动电压至功率开关管40以驱动功率开关管40工作在饱和状态，或者输出第三驱动电压至功率开关管40以驱动功率开关管40关断。
控制单元30与驱动电路10相连，控制单元30用于获取电磁加热系统的目标加热功率，并判断目标加热功率是否小于预设功率，以及在目标加热功率小于预设功率时，在每个控制周期控制电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在放电阶段控制驱动电路10提供多个第一脉冲信号至功率开关管40以使流过功率开关管40的电流小于预设电流值，并在加热阶段控制驱动电路10提供多个第二脉冲信号至功率开关管40，第一脉冲信号的幅值为第一驱动电压，第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。
进一步地，根据本发明的一个实施例，控制单元30还用于在停止阶段持续 输出第三驱动电压至功率开关管40，以驱动功率开关管40关断。
其中，目标加热功率W1是电磁加热系统在不同烹饪参数下所需达到的加热功率。例如，用户想要煮小米粥时，可在电磁加热系统的控制面板上选择煮粥模式，电磁加热系统进入煮粥模式，在煮粥模式下电磁加热系统可以800W的加热功率进行低功率加热，此时对应的目标加热功率为800W。
其中，预设功率W2可为根据实际情况标定的一个功率值，当目标加热功率W1小于预设功率W2时，判断电磁加热系统为低功率加热，而目标加热功率W1大于预设功率W2时，判断电磁加热系统为高功率加热。
根据本发明的一个具体实施例，预设功率W2可为1400W，从而降低频繁启动带来的噪音。
根据本发明的一个实施例，预设电流值可为85A。
需要说明的是，在采用第一驱动电压驱动功率开关管40例如IGBT管时，可使功率开关管40工作在放大状态；在采用第二驱动电压驱动功率开关管例如IGBT管时，可使功率开关管40工作在饱和导通状态。其中，在功率开关管40工作在放大状态时，从图5所示的IGBT管的驱动电压与电流之间的关系可知，控制单元30通过调整提供至IGBT管的驱动电压可限制IGBT管的电流，例如，当提供至IGBT管的驱动电压为9V时，IGBT管的C极电流可恒定在22A左右，由此，采样第一驱动电压驱动IGBT管，可将IGBT管的电流限制在85A以下，从而有效抑制脉冲电流。
根据本发明的一个具体实施例，第一驱动电压V1可大于等于5V且小于等于14.5V，第二驱动电压V2大于等于15V。更具体地，功率开关管40可为IGBT，第一驱动电压V1可优选为9V，当提供至IGBT的第一驱动电压为9V时，IGBT的C极电流可恒定为22A左右，并且IGBT工作在放大状态，从而很好的抑制了脉冲电流。第二驱动电压V2可优选为15V，在第二驱动电压V2的驱动下，IGBT工作在饱和状态。第三驱动电压V3可为0V，在第三驱动电压V3的驱动下，IGBT关断。
具体来说，当目标加热功率W1小于预设功率W2时，如图6-7所示，每个控制周期包括放电阶段D1、加热阶段D2和停止阶段D3，即在每个控制周期内，控制单元30控制谐振电路(如图11中并联的C2和L2)依次进入放电阶段D1、加热阶段D2和停止阶段D3。更具体地，可先进入放电阶段D1，控制单元30控制驱动电路10输出多个第一脉冲信号至功率开关管40的控制端，以使功率开关管40工作在放大状态，从而可将前一个控制周期中停止阶段期间滤波电容(即图11中的C1)存储的电能释放，使得进入加热阶段D2时功率开关40管的集电极电压基本为0V，降低功率开关管40的脉冲电流。在放电阶段D1完成后再进入加热阶段D2，在加热阶段D2，控制单元30控制驱动电路10输出多个第二脉冲信号至功率开关管40的控制端，以使功率开关管40工作在饱和导通状态，此时电磁加热系统可进行正常的谐振加热。并且，在加热阶段D2完成后进入停止阶段D3，在停止阶段D3，控制单元30控制驱动电路10输出第三驱动电压即0V，不输出脉冲信号，功率开关管40关断，此时电磁加热系统停止加热。
并且，可采用占空比方式控制电磁加热系统将进行低功率加热，即在每个控制周期(t1+t2)可控制电磁加热系统先加热t1时间再停止加热t2时间，占空比即为t1/(t1+t2)。具体地，如图6所示，在本发明的一个实施例中，可将控制周期缩短至毫秒极，例如以交流市电的半波周期为单位设置占空比，从而采用毫秒极占空比方式控制电磁加热系统将进行低功率加热，此时占空比可指加热阶段所占的半波数量与整个控制周期所占的半波数之比，例如，控制周期为4个半波时，如果加热1个半波，停止加热3个半波，则占空比为1/4；又如，控制周期为4个半波时，如果加热2个半波，停止加热2个半波，则占空比为2/4；再如，控制周期为4个半波时，如果加热3个半波，停止加热1个半波，则占空比为3/4。
由此，通过预放电方式即采用放电阶段释放滤波电容存储的电能，能够抑制功率开关管的脉冲电流，进而可将控制周期缩短至毫秒极，使得加热效果基 本等同于连续低功率。
根据本发明的一个实施例，可通过交流电源为电磁加热系统供电，如图10所示，装置还包括：过零检测单元50，过零检测单元50与控制单元30相连，过零检测单元50用于获取交流电源的电压过零点，控制单元30用于根据电压过零点控制电磁加热系统进入放电阶段。
需要说明的是，控制单元30可控制谐振电路20在电压过零点附近进入放电阶段，即可在电压过零点之前、电压过零点或电压过零点之后进入放电阶段。
根据本发明的一个实施例，控制单元30还用于在进入放电阶段预设时间后或者在电压过零点控制电磁加热系统进入加热阶段，以使放电阶段处于以电压过零点为中心构造的过零电压区间内
也就是说，可以时间为基准判断放电阶段是否完成，即如果放电阶段的持续时间达到预设时间，控制单元30则控制谐振电路退出放电阶段，进入加热阶段。或者，也可以电压过零点判断放电阶段是否完成，即如果检测到电压过零点，控制单元30则控制谐振电路退出放电阶段，进入加热阶段。
其中，电压过零区间为[-5ms，5ms]。也就是说，放电阶段可处于电压过零点前后5ms内。
另外，在本发明的一个实施例中，控制单元30还可根据电压过零点控制电磁加热系统进入停止阶段。
具体地，结合图6的实施例，假设根据目标加热功率选择2/4占空比的低功率加热，那么整个控制周期为4个半波，加热周期接近2个半波。控制单元30可以如下方式进行加热控制：
控制单元30可在第一个过零点A1之前控制电磁加热系统进入放电阶段D1，例如可以先估算出第一个过零点A1，然后根据估算出的第一个过零点A1和放电阶段D1需持续的预设时间获取放电阶段D1的开始时刻，在开始时刻控制单元30控制电磁加热系统进入放电阶段D1，即控制驱动电路10输出幅值为第一驱动电压V1的第一脉冲信号至功率开关管，以使功率开关管40工作在放 大状态。
控制单元30在控制驱动电路10输出第一脉冲信号的过程中，通过过零检测单元50实时检测电压过零点，并在检测到电压过零点即第一个过零点A1时，控制电磁加热系统进入加热阶段D2，即控制单元30控制驱动电路10输出幅值为第二驱动电压V2的第二脉冲信号至功率开关管40的控制端，以使功率开关管40工作在饱和导通状态，此时电磁加热系统可进行正常的谐振加热。
加热阶段D2的持续时间接近两个半波周期，控制单元30在控制驱动电路10输出第二脉冲信号的过程中，继续，通过过零检测单元50实时检测电压过零点，并在检测到第三个过零点A3时，控制电磁加热系统进入停止阶段D3，即控制单元30控制驱动电路10持续输出第三驱动电压即0V至功率开关管40的控制端，以驱动功率开关管40关断，电磁加热系统停止加热。
停止阶段D3的持续时间接近两个半波周期，在停止阶段D3，控制单元30可以先估算出第五个过零点A5，然后根据估算出的第五个过零点A5和放电阶段D1需持续的预设时间获取下一个控制周期中放电阶段D1的开始时刻。
如此重复，可实现毫秒级占空比的低功率加热，使得加热效果基本等同于连续低功率。
根据本发明的一个实施例，如图7所示，多个第一脉冲信号的脉冲宽度逐渐增加，且相邻两个第一脉冲信号的脉冲宽度的差值小于等于预设宽度阈值。
应当理解的是，脉冲宽度可指高电平的持续时间，多个第一脉冲信号的脉冲宽度逐渐增加是指多个第一脉冲信号的脉冲宽度的整体趋势是递增的，递增方式可为多种，包括但不限于，按照相同的预设增量依次增加，或者按照不同的预设增量依次增加，或者在增加过程中可使得连续的多个脉冲宽度保持不变。
具体来说，如图7所示，假设在放电阶段D1，驱动电路输出M个第一脉冲信号至功率开关管，以释放在前一个停止阶段D3滤波电容存储的电能，其中，M个脉冲信号的脉冲宽度可以分别为Y1、Y2、…、Ym-2、Ym-1、Ym，当脉冲宽度逐渐增加时，M个脉冲信号的脉冲宽度之间可满足以下关系：Ym ≥Ym-1≥Ym-2，…，≥Y2≥Y1。更具体地，每两个相邻的第一脉冲信号的脉冲宽度差值可相等，即按照相同的预设增量依次增加；或者存在两个相邻第一脉冲信号的脉冲宽度的差值为零，即可使得连续的多个脉冲宽度保持不变。
另外，根据本发明的一个实施例，多个第一脉冲信号的脉冲宽度也可相同或逐渐减小。也就是说，当脉冲宽度相同时，M个脉冲信号的脉冲宽度之间可满足以下关系：Ym＝Ym-1＝Ym-2，…，＝Y2＝Y1，或者，当脉冲宽度逐渐减小时，M个脉冲信号的脉冲宽度之间可满足以下关系：满足Ym≤Ym-1≤Ym-2，…，≤Y2≤Y1。
其中，根据本发明的一个实施例，其中，预设宽度阈值的取值范围可为1.5us-2.5us，优选为2us，第一个第一脉冲信号的脉冲宽度即Y1可大于等于0.1us且小于等于10us。
需要说明的是，任一个第一脉冲信号的脉冲宽度小于每个第二脉冲信号的脉冲宽度。换言之，放电阶段提供的多个第一脉冲信号的脉冲宽度均小于加热阶段提供的多个第二脉冲信号的脉冲宽度中的最小脉冲宽度。具体地，假设多个第二脉冲信号的脉冲宽度均为Yn，那么，Ym、Ym-1、Ym-2、…、Y2、Y1均小于Yn。
另外，根据本发明的一个实施例，目标加热功率W1大于或等于预设功率W2时，控制单元30可采用单一的第二驱动电压驱动功率开关管40，此时电磁加热系统可进行连续高功率加热。
还需说明的是，如图8和11所示，电磁加热系统的驱动电路10可包括驱动模块11和变压模块12，驱动模块11用于输出驱动脉冲信号至功率开关管30以驱动功率开关管30导通或关断，变压模块12用于调整驱动脉冲信号的驱动电压。电磁加热系统的控制单元30具有第一控制输出端PPG和第二控制输出端EN，第一控制输出端PPG与驱动模块11相连，第二控制输出端EN与变压模块12相连，控制单元30在通过第一控制输出端PPG输出第一控制信号例如PPG信号并通过第二控制输出端EN输出第二控制信号例如高电平信号时，变 压模块12进行变压以将驱动脉冲信号的驱动电压调整为第一驱动电压V1，驱动电路10可提供幅值为第一驱动电压V1的第一脉冲信号至功率开关管40；控制单元30在通过第一控制输出端PPG输出第一控制信号例如PPG信号并通过第二控制输出端EN输出第三控制信号例如低电平信号时，变压模块12不进行变压，驱动脉冲信号的驱动电压保持为第二驱动电压V2，驱动电路10可提供幅值为第二驱动电压V2的第二脉冲信号至功率开关管40。
综上所述，根据本发明实施例提出的电磁加热系统的加热控制装置，当目标加热功率小于预设功率时，在每个控制周期，控制单元控制电磁加热系统的谐振电路依次进入放电阶段、加热阶段和停止阶段，其中，在放电阶段提供多个第一脉冲信号至谐振电路的功率开关管以使流过功率开关管的电流小于预设电流值，并在加热阶段提供多个第二脉冲信号至功率开关管，第一脉冲信号的幅值为第一驱动电压，第二脉冲信号的幅值为第二驱动电压，且第一驱动电压小于第二驱动电压。由此，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
另外，本发明实施例还提出了一种电磁加热系统。
图12是根据本发明实施例的电磁加热系统的方框示意图。如图12所示，电磁加热系统60包括：上述实施例的电磁加热系统的加热控制装置70。
根据本发明的一个实施例，电磁加热系统60适用于电磁炉、电磁灶、电磁电饭煲或电磁压力锅等。
根据本发明实施例提出的电磁加热系统，通过预放电方式，能够抑制功率开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
最后，本发明实施例还提出了一种电磁加热设备，包括上述实施例的电磁加热系统。
根据本发明的一个实施例，电磁加热设备可为电磁炉、电磁灶、电磁电饭煲或电磁压力锅等。
根据本发明实施例提出的电磁加热设备，通过预放电方式，能够抑制功率 开关管的脉冲电流，进而实现毫秒极占空比的低功率加热，提高用户体验。
在本发明的描述中，需要理解的是，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本发明和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本发明的限制。
此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本发明的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。
在本发明中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系，除非另有明确的限定。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本发明中的具体含义。
在本发明中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。
在本说明书的描述中，参考术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本发明的至少一个实施例或示例中。在本说明 书中，对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外，在不相互矛盾的情况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。
尽管上面已经示出和描述了本发明的实施例，可以理解的是，上述实施例是示例性的，不能理解为对本发明的限制，本领域的普通技术人员在本发明的范围内可以对上述实施例进行变化、修改、替换和变型。
本技术领域的普通技术人员可以理解实现上述实施例方法携带的全部或部分步骤是可以通过程序来指令相关的硬件完成，所述的程序可以存储于一种计算机可读存储介质中，该程序在执行时，包括方法实施例的步骤之一或其组合。
此外，在本发明各个实施例中的各功能单元可以集成在一个处理模块中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个模块中。上述集成的模块既可以采用硬件的形式实现，也可以采用软件功能模块的形式实现。所述集成的模块如果以软件功能模块的形式实现并作为独立的产品销售或使用时，也可以存储在一个计算机可读取存储介质中。
上述提到的存储介质可以是只读存储器，磁盘或光盘等。

Claims (23)

  1. 一种电磁加热系统的加热控制方法，其特征在于，包括以下步骤：
    获取所述电磁加热系统的目标加热功率；
    判断所述目标加热功率是否小于预设功率；
    如果所述目标加热功率小于所述预设功率，则在每个控制周期，控制所述电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在所述放电阶段提供多个第一脉冲信号至所述电磁加热系统的谐振电路的功率开关管以使流过所述功率开关管的电流小于预设电流值，并在所述加热阶段提供多个第二脉冲信号至所述功率开关管，所述第一脉冲信号的幅值为第一驱动电压，所述第二脉冲信号的幅值为第二驱动电压，且所述第一驱动电压小于所述第二驱动电压。
  2. 根据权利要求1所述的电磁加热系统的加热控制方法，其特征在于，其中，在所述停止阶段持续输出第三驱动电压至所述功率开关管，以驱动所述功率开关管关断。
  3. 根据权利要求1所述的电磁加热系统的加热控制方法，其特征在于，所述多个第一脉冲信号的脉冲宽度逐渐增加，且相邻两个第一脉冲信号的脉冲宽度的差值小于等于预设宽度阈值。
  4. 根据权利要求3所述的电磁加热系统的加热控制方法，其特征在于，其中，所述预设宽度阈值的取值范围为1.5us-2.5us。
  5. 根据权利要求3所述的电磁加热系统的加热控制方法，其特征在于，其中，第一个第一脉冲信号的脉冲宽度大于等于0.1us且小于等于10us。
  6. 根据权利要求3所述的电磁加热系统的加热控制方法，其特征在于，通过交流电源为所述电磁加热系统供电，所述方法还包括：
    获取所述交流电源的电压过零点；
    根据所述电压过零点控制所述电磁加热系统进入所述放电阶段。
  7. 根据权利要求6所述的电磁加热系统的加热控制方法，其特征在于，还 包括：在进入所述放电阶段预设时间后或者在所述电压过零点控制所述电磁加热系统进入所述加热阶段，以使所述放电阶段处于以所述电压过零点为中心构造的过零电压区间内。
  8. 根据权利要求7所述的电磁加热系统的加热控制方法，其特征在于，其中，所述电压过零区间为[-5ms，5ms]。
  9. 根据权利要求1所述的电磁加热系统的加热控制方法，其特征在于，所述预设电流值为85A。
  10. 根据权利要求1或9所述的电磁加热系统的加热控制方法，其特征在于，所述第一驱动电压大于等于5V且小于等于14.5V，所述第二驱动电压大于等于15V。
  11. 一种电磁加热系统的加热控制装置，其特征在于，包括：
    谐振电路，所述谐振电路包括功率开关管；
    驱动电路，所述驱动电路与所述功率开关管的控制端相连，所述驱动电路用于输出第一驱动电压至所述功率开关管以驱动所述功率开关管工作在放大状态，或者输出第二驱动电压至所述功率开关管以驱动所述功率开关管工作在饱和状态，或者输出第三驱动电压至所述功率开关管以驱动所述功率开关管关断；
    控制单元，所述控制单元与所述驱动电路相连，所述控制单元用于获取所述电磁加热系统的目标加热功率，并判断所述目标加热功率是否小于预设功率，以及在所述目标加热功率小于所述预设功率时，在每个控制周期控制所述电磁加热系统依次进入放电阶段、加热阶段和停止阶段，其中，在所述放电阶段控制所述驱动电路提供多个第一脉冲信号至所述功率开关管以使流过所述功率开关管的电流小于预设电流值，并在所述加热阶段控制所述驱动电路提供多个第二脉冲信号至所述功率开关管，所述第一脉冲信号的幅值为所述第一驱动电压，所述第二脉冲信号的幅值为所述第二驱动电压，且所述第一驱动电压小于所述第二驱动电压。
  12. 根据权利要求11所述的电磁加热系统的加热控制装置，其特征在于， 所述控制单元还用于在所述停止阶段持续输出第三驱动电压至所述功率开关管，以驱动所述功率开关管关断。
  13. 根据权利要求11所述的电磁加热系统的加热控制装置，其特征在于，所述多个第一脉冲信号的脉冲宽度逐渐增加，且相邻两个第一脉冲信号的脉冲宽度的差值小于等于预设宽度阈值。
  14. 根据权利要求13所述的电磁加热系统的加热控制装置，其特征在于，其中，所述预设宽度阈值的取值范围为1.5us-2.5us。
  15. 根据权利要求13所述的电磁加热系统的加热控制装置，其特征在于，其中，第一个第一脉冲信号的脉冲宽度大于等于0.1us且小于等于10us。
  16. 根据权利要求13所述的电磁加热系统的加热控制装置，其特征在于，通过交流电源为所述电磁加热系统供电，所述装置还包括：
    过零检测单元，所述过零检测单元与所述控制单元相连，所述过零检测单元用于获取所述交流电源的电压过零点，所述控制单元用于根据所述电压过零点控制所述电磁加热系统进入所述放电阶段。
  17. 根据权利要求16所述的电磁加热系统的加热控制装置，其特征在于，所述控制单元还用于在进入所述放电阶段预设时间后或者在所述电压过零点控制所述电磁加热系统进入所述加热阶段，以使所述放电阶段处于以所述电压过零点为中心构造的过零电压区间内。
  18. 根据权利要求17所述的电磁加热系统的加热控制装置，其特征在于，其中，所述电压过零区间为[-5ms，5ms]。
  19. 根据权利要求11所述的电磁加热系统的加热控制装置，其特征在于，所述预设电流值为85A。
  20. 根据权利要求11或19所述的电磁加热系统的加热控制装置，其特征在于，所述第一驱动电压大于等于5V且小于等于14.5V，所述第二驱动电压大于等于15V。
  21. 一种电磁加热系统，其特征在于，包括根据权利要求11-20中任一项 所述的电磁加热系统的加热控制装置。
  22. 一种电磁加热设备，其特征在于，包括根据权利要求21所述的电磁加热系统。
  23. 根据权利要求22所述的电磁加热设备，其特征在于，所述电磁加热设备为电磁炉、电磁灶、电磁电饭煲或电磁压力锅。
PCT/CN2017/086211 2017-02-10 2017-05-26 电磁加热设备、电磁加热系统及其加热控制方法和装置 Ceased WO2018145374A1 (zh)

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