Variable-frequency power supply, driving control circuit of cooking equipment and cooking equipment
By using MOS tube combination to replace insulated gate bipolar transistors in the variable frequency power supply and using capacitors to equalize the voltage, the problem of tailing current and loss of insulated gate bipolar transistors at high frequencies is solved, further miniaturization and cost reduction of inverter power supply is achieved.
Patent Information
- Application Number
- CN202510123177.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-24
- Publication Date
- 2025-05-23
AI Technical Summary
Insulated gate bipolar transistors have tailing current and loss problems at high switching frequency, which limits the further miniaturization of variable frequency power supplies.
The first MOS tube and the second MOS tube combination are used instead of the insulated gate bipolar transistor, and the MOS tube is equalized by the first capacitor and the second capacitor to improve its withstand voltage capability and reduce losses.
The stable operation of MOS tubes at higher switching frequency is achieved, which reduces the requirements for core area, further miniaturizes the frequency converter power supply, and reduces the cost and power consumption of the frequency converter power supply.
Smart Images
Figure CN120034015A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of circuit technology, and in particular to a variable frequency power supply, a driving control circuit of a cooking device, and a cooking device. Background Art
[0002] In the related technical solution, the variable frequency power supply used in the microwave oven adopts an insulated-gate bipolar transistor (IGBT) as a switch tube.
[0003] Specifically, Figure 1 The topology diagram of the variable frequency power supply in the related technical solution is shown as follows: Figure 1 As shown, the variable frequency power supply includes a DC power supply Vcc', a switch tube Q1', a first capacitor C1', a first inductor L1' and a second inductor L2', wherein the switch tube Q1' is used to implement switching.
[0004] For the variable frequency power supply, the switch tube Q1' adopts an insulated gate bipolar transistor. When the insulated gate bipolar transistor operates at a higher switching frequency, the requirement for the magnetic core area can be reduced. When the magnetic core area is small, the variable frequency power supply can be miniaturized.
[0005] However, Figure 2 A schematic diagram of current and voltage on an insulated gate bipolar transistor in a related technical solution is shown, such as Figure 2 As shown, the switching speed of the insulated gate bipolar transistor is slow and there is a tail current. When the switching frequency of the insulated gate bipolar transistor is low, the loss generated by the insulated gate bipolar transistor is small, and when the switching frequency of the insulated gate bipolar transistor is high, the loss generated by the insulated gate bipolar transistor is large.
[0006] Obviously, due to the problems of tail current and loss, the switching frequency of the insulated gate bipolar transistor cannot be further increased, which limits the further reduction of the size of the variable frequency power supply. Summary of the invention
[0007] The present invention aims to at least solve the problem of tail current and loss in the prior art or related art, which makes it impossible to further increase the switching frequency of the insulated gate bipolar transistor, thereby limiting the technical problem of further reducing the size of the variable frequency power supply.
[0008] To this end, a first aspect of the present invention is to provide a variable frequency power supply.
[0009] A second aspect of the present invention provides a driving control circuit for a cooking device.
[0010] A third aspect of the present invention provides a cooking device.
[0011] In view of this, according to a first aspect of the present invention, the present invention provides a variable frequency power supply, comprising: a first capacitor, a first end of the first capacitor is used to be connected to a first end of a DC power supply; a second capacitor, a first end of the second capacitor is connected to a first end of the first capacitor; a first inductor, a first end of the first inductor is connected to a first end of the first capacitor; a second inductor, a first end of the second inductor is connected to a second end of the first inductor, and a second end of the second inductor is connected to a second end of the second capacitor, the second inductor is a primary coil of a transformer in the variable frequency power supply, and the first inductor is a leakage inductance of the primary coil; a first MOS transistor, a first end of the first MOS transistor is connected to a second end of the second inductor, and a second end of the first MOS transistor is connected to a second end of the first capacitor; a second MOS transistor, a first end of the second MOS transistor is connected to a second end of the first capacitor, and a second end of the second MOS transistor is connected to a second end of the DC power supply; wherein the variable frequency power supply is powered based on the on-off output of the first MOS transistor and the second MOS transistor.
[0012] The present invention provides a variable frequency power supply, which includes a first capacitor, a second capacitor, a first inductor, a second inductor, a first MOS transistor and a second MOS transistor. The first capacitor and the second capacitor are used together to balance the voltage of the first MOS transistor and the second MOS transistor. At this time, the first MOS transistor and the second MOS transistor can be used in combination to replace the insulated gate bipolar transistor used in the related technical solution.
[0013] Among them, Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is referred to as metal-oxide-semiconductor field-effect transistor, where MOS is the abbreviation of MOSFET.
[0014] In this process, the first MOS tube and the second MOS tube can operate at a higher switching frequency. Therefore, when the first MOS tube and the second MOS tube are used as the switching tubes of the variable frequency power supply, the requirement for the magnetic core area can be further reduced, so that the magnetic core area is further reduced. While the magnetic core area is reduced, the volume of the variable frequency power supply can be further reduced, so that the variable frequency power supply can be miniaturized.
[0015] In addition, although the use of MOS tubes can avoid the problem of tail current that exists when using insulated gate bipolar transistors as switch tubes, MOS tubes have the problem of low withstand voltage.
[0016] Based on this, the first capacitor and the second capacitor can be used together to balance the voltage of the first MOS tube and the second MOS tube, so that the first MOS tube and the second MOS tube can withstand a higher voltage together. At this time, the voltage borne by each of the first MOS tube and the second MOS tube will be reduced.
[0017] For MOS tubes, the voltage they bear, that is, the withstand voltage value is positively correlated with the price. Since the first MOS tube and the second MOS tube are connected in series to divide the voltage, MOS tubes with smaller withstand voltage values can be used in combination to withstand higher voltages. Obviously, the application of the technical solution of the present invention can reduce the cost of the variable frequency power supply.
[0018] In addition, the variable frequency power supply proposed by the present invention also has the following additional technical features.
[0019] In some technical solutions, optionally, the variable frequency power supply switches in sequence from mode one, mode two, mode three, mode four, mode five and mode six to output power supply; wherein, in mode one, the first MOS tube and the second MOS tube are in a conducting state until the first voltage value on the first capacitor and the second voltage value on the second capacitor are the same as the output voltage of the DC power supply; in mode two, the second MOS tube is in a cut-off state, the first MOS tube is in a conducting state, the first capacitor, the second capacitor, the first inductor and the second inductor resonate, and when the voltage value on the second MOS tube rises to a third voltage value, the first MOS tube is controlled to be cut off; in mode three, the second capacitor, the first inductor and the second inductor are in a cut-off state, and the first MOS tube is in a conducting state. Inductor resonates until the second voltage value on the second capacitor resonates to the negative voltage peak; in mode four, when the second voltage value on the second capacitor resonates to be greater than the first voltage value on the first capacitor, the anti-parallel diode of the first MOS tube is turned on; in mode five, the first capacitor, the second capacitor, the first inductor and the second inductor resonate, the first voltage value on the first capacitor and the second voltage value on the second capacitor resonate to be greater than the output voltage of the DC power supply, and the anti-parallel diode of the second MOS tube is turned on; in mode six, when the first voltage value on the first capacitor and the second voltage value on the second capacitor are the same as the output voltage of the DC power supply, the first MOS tube and the second MOS tube are controlled to be turned on.
[0020] In this technical solution, the variable frequency power supply switches in sequence among mode one, mode two, mode three, mode four, mode five and mode six, so that the first MOS tube and the second MOS tube can be turned on and off with zero voltage drop.
[0021] Under the condition of zero voltage drop, the first MOS tube and the second MOS tube are controlled to be turned on and off, so that the switching loss of the first MOS tube and the second MOS tube is almost equal to zero whether the first MOS tube and the second MOS tube are turned on or off. Obviously, in this process, compared with the insulated gate bipolar transistor in the related technical solution, the loss of the variable frequency power supply can be reduced.
[0022] Specifically, in mode 1, the DC power supply charges the first capacitor and the second capacitor. As the charging progresses, the first voltage value on the first capacitor and the second voltage value on the second capacitor will continue to increase until the first voltage value and the second voltage value are both equal to the output voltage of the DC power supply. At this time, the voltage drop between the first end of the second MOS tube and the second end of the second MOS tube is equal to zero. Obviously, when entering mode 2 to control the second MOS tube to be cut off, the voltage drop between the first end of the second MOS tube and the second end of the second MOS tube is always equal to zero. At this time, the second MOS tube can achieve zero voltage shutdown.
[0023] In this process, the loss generated when the second MOS tube is turned off can be reduced, thereby reducing the power consumption of the variable frequency power supply.
[0024] After the second MOS tube is turned off, a resonant circuit is formed between the first capacitor, the second capacitor, the first inductor and the second inductor. The resonant circuit resonates. Since the first end of the second MOS tube is connected to the second end of the first capacitor, and the second end of the second MOS tube is connected to the second end of the DC power supply, the voltage borne by the second MOS tube is the voltage difference between the output voltage of the DC power supply and the second voltage value on the second capacitor. As the resonant circuit resonates, the second voltage value on the second capacitor will continue to decrease. Obviously, the voltage borne by the second MOS tube will continue to increase.
[0025] Since the first end of the first MOS tube is connected to the second end of the second capacitor, the second end of the first MOS tube is connected to the second end of the first capacitor, and the first capacitor and the second capacitor participate in resonance at the same time, the first voltage value on the first capacitor and the second voltage value on the second capacitor will eventually approach the same. Therefore, when the voltage value on the second MOS tube increases to the third voltage value, it can be considered that the first voltage value on the first capacitor and the second voltage value on the second capacitor are approaching the same. At this time, the voltage drop between the first end and the second end of the first MOS tube is also equal to zero. At this time, the first MOS tube is controlled to be cut off, so that the zero voltage shutdown of the first MOS tube can be achieved.
[0026] In this process, the loss generated when the first MOS tube is turned off can be reduced, thereby reducing the power consumption of the variable frequency power supply.
[0027] In mode three, since the first MOS tube and the second MOS tube are in the cut-off state at the same time, there is no path for releasing the electric energy on the first capacitor. Therefore, the first voltage value on the first capacitor will remain unchanged. At this time, the voltage borne by the second MOS tube will not change. At this time, the second capacitor will form a resonant circuit with the first inductor and the second inductor and resonate. At this time, the resonant frequency of the resonant circuit formed by the second capacitor, the first inductor and the second inductor is different from the resonant frequency of the resonant circuit formed before.
[0028] In mode four, when the second voltage value on the second capacitor resonates to the negative voltage peak, the current in the resonant circuit formed by the second capacitor, the first inductor and the second inductor will flow in the opposite direction, and the second capacitor discharges to the first inductor and the second inductor, so that the first inductor and the second inductor are charged, and the second voltage value on the second capacitor resonates to the first voltage value on the first capacitor. At this time, the anti-parallel diode on the first MOS tube is turned on.
[0029] In mode five, when the anti-parallel diode of the first MOS tube is turned on, the first capacitor, the second capacitor, the first inductor and the second inductor form a resonant circuit again and resonate. At this time, the first voltage value on the first capacitor and the second voltage value on the second capacitor will continue to increase until they are greater than the output voltage of the DC power supply. In this case, the anti-parallel diode of the second MOS tube will be turned on, and mode six will be entered.
[0030] In mode six, the anti-parallel diode of the first MOS tube and the anti-parallel diode of the second MOS tube are turned on. At this time, the voltage drop between the first end and the second end of the first MOS tube and the first end and the second end of the second MOS tube is zero. At this time, the first MOS tube and the second MOS tube can be controlled to be turned on, and the mode can be cycled from mode six to mode one.
[0031] In this technical solution, the first capacitor can be used to control the voltage across the second MOS tube. The first capacitor and the second capacitor are used together to control the voltage across the first MOS tube, thereby achieving repeated use of the first capacitor.
[0032] In some technical solutions, optionally, the third voltage value is a withstand voltage value of the second MOS tube.
[0033] In some technical solutions, optionally, the first MOS transistor and the second MOS transistor are silicon metal-oxide semiconductor field effect transistors.
[0034] In this technical solution, the silicon metal-oxide semiconductor field effect transistor is selected to reduce the manufacturing cost of the variable frequency power supply.
[0035] A second aspect of the present invention is to provide a driving control circuit for a cooking device, comprising: a variable frequency power supply as described in any one of the above.
[0036] In some technical schemes, optionally, the driving control circuit of the cooking device also includes: a third inductor; a fourth inductor, a first end of the fourth inductor is connected to the first end of the third inductor; a voltage doubler circuit, a first input end of the voltage doubler circuit is connected to the second end of the third inductor, a second input end of the voltage doubler circuit is connected to the second end of the fourth inductor, a first output end of the voltage doubler circuit is used to connect to the magnetron of the cooking device, and a second output end of the voltage doubler circuit is grounded; wherein the third inductor is the secondary coil of the transformer, and the fourth inductor is the leakage inductance of the secondary coil.
[0037] In this technical solution, the second inductor and the third inductor serve as the primary coil and the secondary coil of the transformer, which can realize power transfer and voltage conversion under the action of the same magnetic core. In this process, they can provide power to the voltage doubler circuit and then to the magnetron.
[0038] In this process, while the third inductor and the fourth inductor are used to output power to the outside, the voltage is changed by using the voltage doubling circuit to meet the power supply requirement of the magnetron.
[0039] In this technical solution, a variable frequency power supply can be used to supply power to the voltage doubling circuit. When the volume of the variable frequency power supply is miniaturized, the area of the circuit board where the driving control circuit of the cooking device is located can be reduced, thereby miniaturizing the driving control circuit of the cooking device.
[0040] In some technical schemes, optionally, the voltage doubling circuit includes: a first diode, a cathode of the first diode is connected to the second end of the fourth inductor; a second diode, an anode of the second diode is connected to the cathode of the first diode; a third capacitor, a first end of the third capacitor is connected to the anode of the first diode, and a second end of the third capacitor is connected to the second end of the third inductor; a fourth capacitor, a first end of the fourth capacitor is connected to the second end of the third capacitor, and a second end of the fourth capacitor is connected to the cathode of the second diode.
[0041] In this technical solution, the first diode, the second diode, the third capacitor and the fourth capacitor can convert the alternating current output by the third inductor and the fourth inductor into direct current with a higher voltage, thereby supplying power to the magnetron.
[0042] In this process, with the cooperation of diodes and capacitors, AC power can be converted into DC power, and the voltage of AC power can be converted into DC power, thereby outputting high-voltage DC power to the magnetron.
[0043] Compared with other circuits for AC-to-DC conversion and voltage adjustment, the voltage doubling circuit proposed in the present invention can achieve both AC-to-DC conversion and voltage adjustment, thereby reducing the manufacturing cost of the cooking device.
[0044] Exemplarily, the voltage doubling circuit can convert the 2 kilovolt alternating current output by the third inductor and the fourth inductor into 4 kilovolt direct current to supply power to the magnetron.
[0045] In some technical solutions, optionally, the driving control circuit of the cooking device also includes: a first resistor, a first end of the first resistor is connected to the first end of the third capacitor, and the first end of the first resistor is connected to the second end of the fourth capacitor.
[0046] In the above technical solution, when the voltage doubler circuit is working, it can convert the input voltage into high-voltage direct current. When the voltage doubler circuit stops working, the electric energy will be stored in the third capacitor and the fourth capacitor. The stored electric energy will have the risk of leakage, so that the driving control circuit of the cooking equipment has electrical safety.
[0047] In the technical solution of the present invention, a first resistor is provided on the basis of the voltage doubling circuit so as to utilize the first resistor to discharge the electric energy stored in the third capacitor and the fourth capacitor, thereby improving the safety of the above-mentioned drive control circuit.
[0048] In some technical solutions, the resistance value of the first resistor can be determined according to actual usage requirements, and its specific value will not be repeated here.
[0049] A third aspect of the present invention is to provide a cooking device, comprising: a variable frequency power supply as described in any one of the above items; or a driving control circuit of the cooking device as described in any one of the above items.
[0050] In some technical solutions, optionally, the cooking device includes a microwave oven or a microwave oven-steamer-oven.
[0051] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0052] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:
[0053] Figure 1 A topological schematic diagram of a variable frequency power supply in a related technical solution is shown;
[0054] Figure 2 A schematic diagram showing the current and voltage on an insulated gate bipolar transistor in a related technical solution is shown:
[0055] Figure 3 A topological schematic diagram of a driving control circuit of a cooking device according to an embodiment of the present invention is shown;
[0056] Figure 4One of the principle schematic diagrams of a variable frequency power supply in an embodiment of the present invention is shown;
[0057] Figure 5 The second schematic diagram of the principle of a variable frequency power supply in an embodiment of the present invention is shown;
[0058] Figure 6 The third schematic diagram of the principle of a variable frequency power supply in an embodiment of the present invention is shown;
[0059] Figure 7 A fourth schematic diagram of the principle of a variable frequency power supply in an embodiment of the present invention is shown;
[0060] Figure 8 The fifth schematic diagram of the principle of a variable frequency power supply in an embodiment of the present invention is shown;
[0061] Fig. 9 The sixth schematic diagram of the principle of a variable frequency power supply in an embodiment of the present invention is shown;
[0062] Fig.10 FIG7 shows a seventh schematic diagram of the principle of a variable frequency power supply in an embodiment of the present invention;
[0063] Fig.11 A schematic diagram showing the states of various components in a variable frequency power supply according to an embodiment of the present invention is shown.
[0064] in, Figure 1 The corresponding relationship between the reference numerals and the component names is as follows:
[0065] Vcc' is a DC power supply, C1' is a first capacitor, L1' is a first inductor, L2' is a second inductor, and Q1' is a switch tube.
[0066] in, Figures 3 to 10 The corresponding relationship between the reference numerals and the component names is as follows:
[0067] 100 variable frequency power supply, 102 voltage doubling circuit, C1 first capacitor, C2 second capacitor, C3 third capacitor, C4 fourth capacitor, L1 first inductor, L2 second inductor, L3 third inductor, L4 fourth inductor, Q1 first MOS tube, Q2 second MOS tube, R1 first resistor, 200 driving control circuit of cooking equipment, Vcc DC power supply, D1 first diode, D2 second diode. DETAILED DESCRIPTION
[0068] In order to more clearly understand the above aspects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.
[0069] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.
[0070] In one embodiment of the present application, Figure 3 and Figure 4 As shown, a variable frequency power supply 100 is provided, comprising: a first capacitor C1, a first end of the first capacitor C1 is used to be connected to a first end of a DC power supply Vcc; a second capacitor C2, a first end of the second capacitor C2 is connected to a first end of the first capacitor C1; a first inductor L1, a first end of the first inductor L1 is connected to a first end of the first capacitor C1; a second inductor L2, a first end of the second inductor L2 is connected to a second end of the first inductor L1, a second end of the second inductor L2 is connected to a second end of the second capacitor C2, and the second inductor L2 is a first end of the variable frequency power supply 100 The primary coil of the transformer, the first inductor L1 is the leakage inductance of the primary coil; the first MOS tube Q1, the first end of the first MOS tube Q1 is connected to the second end of the second inductor L2, and the second end of the first MOS tube Q1 is connected to the second end of the first capacitor C1; the second MOS tube Q2, the first end of the second MOS tube Q2 is connected to the second end of the first capacitor C1, and the second end of the second MOS tube Q2 is connected to the second end of the DC power supply Vcc; wherein the variable frequency power supply 100 is powered based on the on-off output of the first MOS tube Q1 and the second MOS tube Q2.
[0071] The present invention proposes a variable frequency power supply 100, which includes a first capacitor C1, a second capacitor C2, a first inductor L1, a second inductor L2, a first MOS transistor Q1, and a second MOS transistor Q2. The first capacitor C1 and the second capacitor C2 are used together to balance the voltage of the first MOS transistor Q1 and the second MOS transistor Q2. At this time, the first MOS transistor Q1 and the second MOS transistor Q2 can be used in combination to replace the insulated gate bipolar transistor used in the relevant embodiments.
[0072] Among them, Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is referred to as metal-oxide-semiconductor field-effect transistor, where MOS is the abbreviation of MOSFET.
[0073] In this process, the first MOS transistor Q1 and the second MOS transistor Q2 can operate at a higher switching frequency. Therefore, when the first MOS transistor Q1 and the second MOS transistor Q2 are used as the switching transistors of the variable frequency power supply 100, the requirement for the magnetic core area can be further reduced, so that the magnetic core area is further reduced. When the magnetic core area is reduced, the volume of the variable frequency power supply 100 can be further reduced, so that the variable frequency power supply 100 can be miniaturized.
[0074] In addition, although the use of MOS tubes can avoid the problem of tail current that exists when using insulated gate bipolar transistors as switch tubes, MOS tubes have the problem of low withstand voltage.
[0075] Based on this, the first capacitor C1 and the second capacitor C2 can be used together to balance the voltage of the first MOS transistor Q1 and the second MOS transistor Q2, so that the first MOS transistor Q1 and the second MOS transistor Q2 can withstand a higher voltage together. At this time, the voltage borne by each of the first MOS transistor Q1 and the second MOS transistor Q2 will be reduced.
[0076] For MOS tubes, the voltage they bear, that is, the withstand voltage value is positively correlated with the price. Since the first MOS tube Q1 and the second MOS tube Q2 are connected in series to divide the voltage, MOS tubes with smaller withstand voltage values can be used in combination to withstand higher voltages. Obviously, the application of the embodiments of the present invention can reduce the cost of the variable frequency power supply 100.
[0077] In some embodiments, optionally, the variable frequency power supply 100 switches in sequence from mode 1, mode 2, mode 3, mode 4, mode 5 and mode 6 to output power supply; wherein, in mode 1, the first MOS tube Q1 and the second MOS tube Q2 are in an on state until the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 are the same as the output voltage of the DC power supply Vcc; in mode 2, the second MOS tube Q2 is in an off state, the first MOS tube Q1 is in an on state, the first capacitor C1, the second capacitor C2, the first inductor L1 and the second inductor L2 resonate, and when the voltage value on the second MOS tube Q2 rises to a third voltage value, the first MOS tube Q1 is controlled to be off; in mode 3, the second capacitor C2, the first inductor L1 and the second inductor L2 Resonance, until the second voltage value on the second capacitor C2 resonates to the negative voltage peak; in mode four, when the second voltage value on the second capacitor C2 resonates to be greater than the first voltage value on the first capacitor C1, the anti-parallel diode of the first MOS tube Q1 is turned on; in mode five, the first capacitor C1, the second capacitor C2, the first inductor L1 and the second inductor L2 resonate, the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 resonate to be greater than the output voltage of the DC power supply Vcc, and the anti-parallel diode of the second MOS tube Q2 is turned on; in mode six, when the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 are the same as the output voltage of the DC power supply Vcc, the first MOS tube Q1 and the second MOS tube Q2 are controlled to be turned on.
[0078] In this embodiment, the variable frequency power supply 100 switches in sequence among mode 1, mode 2, mode 3, mode 4, mode 5 and mode 6, so that the first MOS transistor Q1 and the second MOS transistor Q2 can be turned on and off with zero voltage drop.
[0079] In the case of zero voltage drop, the first MOS transistor Q1 and the second MOS transistor Q2 are controlled to be turned on and off, so that no matter the first MOS transistor Q1 and the second MOS transistor Q2 are turned on or off, the switching loss of the first MOS transistor Q1 and the second MOS transistor Q2 is almost equal to zero. Obviously, in this process, compared with the insulated gate bipolar transistor in the relevant embodiment, the loss of the variable frequency power supply 100 can be reduced.
[0080] Specifically, Figure 5 and Fig.11 As shown, in mode 1, the DC power supply Vcc charges the first capacitor C1 and the second capacitor C2. As the charging progresses, the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 continue to increase until the first voltage value and the second voltage value are both equal to the output voltage of the DC power supply Vcc. At this time, the voltage drop between the first end of the second MOS tube Q2 and the second end of the second MOS tube Q2 is zero.
[0081] The time for the DC power supply Vcc to charge the first capacitor C1 and the second capacitor C2 is related to the voltage required by the secondary coil of the transformer. If the voltage required by the secondary coil of the transformer is large, the time for the DC power supply Vcc to charge the first capacitor C1 and the second capacitor C2 is long. Conversely, if the voltage required by the secondary coil of the transformer is small, the time for the DC power supply Vcc to charge the first capacitor C1 and the second capacitor C2 is short.
[0082] Obviously, when entering mode 2 to control the second MOS tube Q2 to be turned off, the voltage drop between the first end of the second MOS tube Q2 and the second end of the second MOS tube Q2 is always equal to zero. At this time, the second MOS tube Q2 can achieve zero voltage shutdown.
[0083] In this process, the loss generated when the second MOS tube Q2 is turned off can be reduced, thereby reducing the power consumption of the variable frequency power supply 100.
[0084] like Figure 6 and Fig.11 As shown, in mode 2, after the second MOS tube Q2 is turned off, a resonant circuit is formed between the first capacitor C1, the second capacitor C2, the first inductor L1 and the second inductor L2, and the resonant circuit resonates. Since the first end of the second MOS tube Q2 is connected to the second end of the first capacitor C1, and the second end of the second MOS tube Q2 is connected to the second end of the DC power supply Vcc, the voltage Vm2 borne by the second MOS tube Q2 is the voltage difference between the output voltage of the DC power supply Vcc and the second voltage value on the second capacitor C2, that is, Vm2=Vcs-Vc2. As the resonant circuit resonates, the second voltage value on the second capacitor C2 will continue to decrease. Obviously, the voltage borne by the second MOS tube Q2 will continue to increase.
[0085] Wherein, Vcs is the output voltage of the DC power supply Vcc, Vc1 is the first voltage value on the first capacitor C1, Vc2 is the second voltage value on the second capacitor C2, Vm1 is the voltage value on the first MOS transistor Q1, and Vm2 is the voltage value on the second MOS transistor Q2.
[0086] Since the first end of the first MOS tube Q1 is connected to the second end of the second capacitor C2, the second end of the first MOS tube Q1 is connected to the second end of the first capacitor C1, and the first capacitor C1 and the second capacitor C2 participate in resonance at the same time, finally the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 will approach the same. Therefore, when the voltage value on the second MOS tube Q2 increases to the third voltage value, it can be considered that the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 are approaching the same. At this time, the voltage drop between the first end and the second end of the first MOS tube Q1 is also equal to zero. At this time, the first MOS tube Q1 is controlled to be cut off, so that the zero voltage shutdown of the first MOS tube Q1 can be achieved.
[0087] In this process, the loss generated when the first MOS tube Q1 is turned off can be reduced, thereby reducing the power consumption of the variable frequency power supply 100.
[0088] In mode three, Figure 7 and Fig.11 As shown, when the first MOS tube Q1 and the second MOS tube Q2 are in the cut-off state at the same time, there is no path for releasing the electric energy on the first capacitor C1. Therefore, the first voltage value on the first capacitor C1 will remain unchanged. At this time, the voltage borne by the second MOS tube Q2 will not change. At this time, the second capacitor C2 will form a resonant circuit with the first inductor L1 and the second inductor L2 and resonate. At this time, the resonant frequency of the resonant circuit formed by the second capacitor C2, the first inductor L1 and the second inductor L2 is different from the resonant frequency of the resonant circuit formed before.
[0089] In mode 4, if Figure 8 and Fig.11 As shown, when the second voltage value on the second capacitor C2 resonates to the negative voltage peak, the current in the resonant circuit formed by the second capacitor C2, the first inductor L1 and the second inductor L2 will flow in the opposite direction, and the second capacitor C2 discharges to the first inductor L1 and the second inductor L2, so that the first inductor L1 and the second inductor L2 are charged, and the second voltage value on the second capacitor C2 resonates to the first voltage value on the first capacitor C1. At this time, the anti-parallel diode on the first MOS tube Q1 is turned on.
[0090] In mode five, Fig. 9 and Fig.11 As shown, when the anti-parallel diode of the first MOS tube Q1 is turned on, the first capacitor C1, the second capacitor C2, the first inductor L1 and the second inductor L2 form a resonant circuit again and resonate. At this time, the first voltage value on the first capacitor C1 and the second voltage value on the second capacitor C2 will continue to increase until they are greater than the output voltage of the DC power supply Vcc. In this case, the anti-parallel diode of the second MOS tube Q2 will be turned on, and at this time, mode six is entered.
[0091] In modal six, Fig.10 and Fig.11 As shown, the anti-parallel diode of the first MOS tube Q1 and the anti-parallel diode of the second MOS tube Q2 are turned on. At this time, the voltage drop between the first end and the second end of the first MOS tube Q1 and the first end and the second end of the second MOS tube Q2 is zero. At this time, the first MOS tube Q1 and the second MOS tube Q2 can be controlled to be turned on, and at this time, the mode six can be cycled to the mode one.
[0092] In this embodiment, the first capacitor C1 can be used to control the voltage across the second MOS transistor Q2. The first capacitor C1 and the second capacitor C2 are used together to control the voltage across the first MOS transistor Q1, thereby achieving repeated use of the first capacitor C1.
[0093] In some embodiments, optionally, the third voltage value is a withstand voltage value of the second MOS transistor Q2.
[0094] In some embodiments, optionally, the first MOS transistor Q1 and the second MOS transistor Q2 are silicon metal-oxide semiconductor field effect transistors.
[0095] In this embodiment, the silicon metal-oxide semiconductor field effect transistor is selected to reduce the manufacturing cost of the variable frequency power supply 100.
[0096] In some embodiments, Figure 3 As shown, a driving control circuit 200 of a cooking device is provided, comprising: a variable frequency power supply 100 as any one of the above items.
[0097] The present invention proposes a driving control circuit 200 for a cooking device, which includes a variable frequency power supply 100, and the variable frequency power supply 100 includes a first capacitor C1, a second capacitor C2, a first inductor L1, a second inductor L2, a first MOS transistor Q1, and a second MOS transistor Q2. The first capacitor C1 and the second capacitor C2 are used together to balance the voltage of the first MOS transistor Q1 and the second MOS transistor Q2. At this time, the first MOS transistor Q1 and the second MOS transistor Q2 can be used in combination to replace the insulated gate bipolar transistor used in the relevant embodiments.
[0098] In this process, the first MOS transistor Q1 and the second MOS transistor Q2 can operate at a higher switching frequency. Therefore, when the first MOS transistor Q1 and the second MOS transistor Q2 are used as the switching transistors of the variable frequency power supply 100, the requirement for the magnetic core area can be further reduced, so that the magnetic core area is further reduced. When the magnetic core area is reduced, the volume of the variable frequency power supply 100 can be further reduced, so that the variable frequency power supply 100 can be miniaturized.
[0099] In addition, although the use of MOS tubes can avoid the problem of tail current that exists when using insulated gate bipolar transistors as switch tubes, MOS tubes have the problem of low withstand voltage.
[0100] Based on this, the first capacitor C1 and the second capacitor C2 can be used together to balance the voltage of the first MOS transistor Q1 and the second MOS transistor Q2, so that the first MOS transistor Q1 and the second MOS transistor Q2 can withstand a higher voltage together. At this time, the voltage borne by each of the first MOS transistor Q1 and the second MOS transistor Q2 will be reduced.
[0101] For MOS tubes, the voltage they bear, that is, the withstand voltage value is positively correlated with the price. Since the first MOS tube Q1 and the second MOS tube Q2 are connected in series to divide the voltage, MOS tubes with smaller withstand voltage values can be used in combination to withstand higher voltages. Obviously, the application of the embodiments of the present invention can reduce the cost of the variable frequency power supply 100.
[0102] In some embodiments, optionally, the driving control circuit 200 of the cooking device also includes: a third inductor L3; a fourth inductor L4, wherein the first end of the fourth inductor L4 is connected to the first end of the third inductor L3; a voltage doubler circuit 102, wherein the first input end of the voltage doubler circuit 102 is connected to the second end of the third inductor L3, the second input end of the voltage doubler circuit 102 is connected to the second end of the fourth inductor L4, the first output end of the voltage doubler circuit 102 is used to connect to the magnetron of the cooking device, and the second output end of the voltage doubler circuit 102 is grounded; wherein the third inductor L3 is the secondary coil of the transformer, and the fourth inductor L4 is the leakage inductance of the secondary coil.
[0103] In this embodiment, the second inductor L2 and the third inductor L3 serve as the primary coil and the secondary coil of the transformer, which can realize power transmission and voltage conversion under the action of the same magnetic core. In this process, power can be provided to the voltage doubler circuit 102, and then to the magnetron.
[0104] In this process, while the third inductor L3 and the fourth inductor L4 are used to output power to the outside, the voltage is changed by using the voltage doubling circuit to meet the power supply requirement of the magnetron.
[0105] In this embodiment, the variable frequency power supply 100 can be used to supply power to the voltage doubling circuit 102. When the volume of the variable frequency power supply 100 is miniaturized, the area of the circuit board where the driving control circuit 200 of the cooking device is located can be reduced, so that the driving control circuit 200 of the cooking device can be miniaturized.
[0106] In some embodiments, optionally, the voltage doubling circuit 102 includes: a first diode D1, wherein the cathode of the first diode D1 is connected to the second end of the fourth inductor L4; a second diode D2, wherein the anode of the second diode D2 is connected to the cathode of the first diode D1; a third capacitor C3, wherein the first end of the third capacitor C3 is connected to the anode of the first diode D1, and the second end of the third capacitor C3 is connected to the second end of the third inductor L3; and a fourth capacitor C4, wherein the first end of the fourth capacitor C4 is connected to the second end of the third capacitor C3, and the second end of the fourth capacitor C4 is connected to the cathode of the second diode D2.
[0107] In this embodiment, the first diode D1, the second diode D2, the third capacitor C3 and the fourth capacitor C4 can convert the alternating current output by the third inductor L3 and the fourth inductor L4 into direct current with a higher voltage, thereby supplying power to the magnetron.
[0108] In this process, with the cooperation of diodes and capacitors, AC power can be converted into DC power, and the voltage of AC power can be converted into DC power, thereby outputting high-voltage DC power to the magnetron.
[0109] Compared with other circuits for AC-to-DC conversion and voltage adjustment, the voltage doubling circuit 102 proposed in the present invention can achieve both AC-to-DC conversion and voltage adjustment, thereby reducing the manufacturing cost of the cooking device.
[0110] Exemplarily, the voltage doubler circuit 102 can convert the 2 kilovolt alternating current output by the third inductor L3 and the fourth inductor L4 into 4 kilovolt direct current to supply power to the magnetron.
[0111] In some embodiments, optionally, the driving control circuit 200 of the cooking device further includes: a first resistor R1, a first end of the first resistor R1 is connected to a first end of the third capacitor C3, and a first end of the first resistor R1 is connected to a second end of the fourth capacitor C4.
[0112] In the above embodiment, when the voltage doubling circuit 102 is working, it can convert the input voltage into high-voltage direct current. When the voltage doubling circuit 102 stops working, the electric energy will be stored in the third capacitor C3 and the fourth capacitor C4. The stored electric energy may have the risk of leakage, so that the driving control circuit 200 of the cooking device has electrical safety.
[0113] In the embodiment of the present invention, a first resistor R1 is provided on the basis of the voltage doubling circuit 102 so as to utilize the first resistor R1 to discharge the electric energy stored in the third capacitor C3 and the fourth capacitor C4, thereby improving the safety of the above-mentioned drive control circuit.
[0114] In some embodiments, the resistance value of the first resistor R1 can be determined according to actual usage requirements, and its specific value will not be described in detail here.
[0115] In some embodiments, a cooking device is provided, comprising: a variable frequency power supply 100 as any one of the above items; or a driving control circuit 200 of the cooking device as any one of the above items.
[0116] The present invention proposes a cooking device, which includes a driving control circuit 200 or a variable frequency power supply 100 of the cooking device, and the variable frequency power supply 100 includes a first capacitor C1, a second capacitor C2, a first inductor L1, a second inductor L2, a first MOS transistor Q1, and a second MOS transistor Q2. The first capacitor C1 and the second capacitor C2 are used together to balance the voltage of the first MOS transistor Q1 and the second MOS transistor Q2. At this time, the first MOS transistor Q1 and the second MOS transistor Q2 can be used in combination to replace the insulated gate bipolar transistor used in the relevant embodiments.
[0117] In this process, the first MOS transistor Q1 and the second MOS transistor Q2 can operate at a higher switching frequency. Therefore, when the first MOS transistor Q1 and the second MOS transistor Q2 are used as the switching transistors of the variable frequency power supply 100, the requirement for the magnetic core area can be further reduced, so that the magnetic core area is further reduced. When the magnetic core area is reduced, the volume of the variable frequency power supply 100 can be further reduced, so that the variable frequency power supply 100 can be miniaturized.
[0118] In addition, although the use of MOS tubes can avoid the problem of tail current that exists when using insulated gate bipolar transistors as switch tubes, MOS tubes have the problem of low withstand voltage.
[0119] Based on this, the first capacitor C1 and the second capacitor C2 can be used together to balance the voltage of the first MOS transistor Q1 and the second MOS transistor Q2, so that the first MOS transistor Q1 and the second MOS transistor Q2 can withstand a higher voltage together. At this time, the voltage borne by each of the first MOS transistor Q1 and the second MOS transistor Q2 will be reduced.
[0120] For MOS tubes, the voltage they bear, that is, the withstand voltage value is positively correlated with the price. Since the first MOS tube Q1 and the second MOS tube Q2 are connected in series to divide the voltage, MOS tubes with smaller withstand voltage values can be used in combination to withstand higher voltages. Obviously, the application of the embodiments of the present invention can reduce the cost of the variable frequency power supply 100.
[0121] In some embodiments, optionally, the cooking device includes a microwave oven or a microwave oven-steamer-oven.
[0122] The term "first" or "second" in the specification and claims of the present application may include one or more of the features explicitly or implicitly. In the textual description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.
[0123] In the text description of the present invention, it is understood that, except for explicit provisions and limitations, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be fixed connection, detachable connection, or integral connection; it can be mechanical structure connection or electrical connection; it can be direct connection between the two, or indirect connection between the two through an intermediate medium, or it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0124] In the claims, specification and drawings of the present invention, the description of the terms "one embodiment", "some embodiments", "specific embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the claims, specification and drawings of the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0125] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A variable frequency power supply, characterized in that: include: A first capacitor, wherein a first end of the first capacitor is used to be connected to a first end of a DC power supply; a second capacitor, a first end of the second capacitor being connected to the first end of the first capacitor; a first inductor, wherein a first end of the first inductor is connected to a first end of the first capacitor; a second inductor, wherein a first end of the second inductor is connected to a second end of the first inductor, a second end of the second inductor is connected to a second end of the second capacitor, the second inductor is a primary coil of a transformer in the variable frequency power supply, and the first inductor is a leakage inductance of the primary coil; a first MOS transistor, wherein a first end of the first MOS transistor is connected to a second end of the second inductor, and a second end of the first MOS transistor is connected to a second end of the first capacitor; a second MOS transistor, wherein a first end of the second MOS transistor is connected to a second end of the first capacitor, and a second end of the second MOS transistor is connected to a second end of the DC power supply; The variable frequency power supply is powered based on the on / off output of the first MOS tube and the second MOS tube.
2. The variable frequency power supply according to claim 1, characterized in that: The variable frequency power supply switches in sequence among mode 1, mode 2, mode 3, mode 4, mode 5 and mode 6 to output power; Wherein, in the first mode, the first MOS transistor and the second MOS transistor are in a conducting state until a first voltage value on the first capacitor and a second voltage value on the second capacitor are the same as the output voltage of the DC power supply; In the second mode, the second MOS transistor is in a cut-off state, the first MOS transistor is in a cut-off state, the first capacitor, the second capacitor, the first inductor and the second inductor resonate, and when the voltage value on the second MOS transistor increases to a third voltage value, the first MOS transistor is controlled to be cut off; In the third mode, the second capacitor, the first inductor and the second inductor resonate until the second voltage value on the second capacitor resonates to a negative voltage peak; In the fourth mode, when the second voltage value on the second capacitor resonates to be greater than the first voltage value on the first capacitor, the anti-parallel diode of the first MOS tube is turned on; In the fifth mode, the first capacitor, the second capacitor, the first inductor and the second inductor resonate, a first voltage value on the first capacitor and a second voltage value on the second capacitor resonate to be greater than the output voltage of the DC power supply, and the anti-parallel diode of the second MOS tube is turned on; In the sixth mode, when the first voltage value on the first capacitor and the second voltage value on the second capacitor are the same as the output voltage of the DC power supply, the first MOS transistor and the second MOS transistor are controlled to be turned on.
3. The variable frequency power supply according to claim 2, characterized in that: The third voltage value is the withstand voltage value of the second MOS tube.
4. The variable frequency power supply according to any one of claims 1 to 3, characterized in that: The first MOS transistor and the second MOS transistor are silicon metal-oxide semiconductor field effect transistors.
5. A driving control circuit for a cooking device, characterized in that: include: The variable frequency power supply according to any one of claims 1 to 4.
6. The driving control circuit of the cooking device according to claim 5, characterized in that: The driving control circuit of the cooking device also includes: The third inductor; a fourth inductor, wherein a first end of the fourth inductor is connected to a first end of the third inductor; a voltage doubler circuit, wherein a first input end of the voltage doubler circuit is connected to a second end of the third inductor, a second input end of the voltage doubler circuit is connected to a second end of the fourth inductor, a first output end of the voltage doubler circuit is used to be connected to a magnetron of a cooking device, and a second output end of the voltage doubler circuit is grounded; The third inductor is the secondary coil of the transformer, and the fourth inductor is the leakage inductance of the secondary coil.
7. The driving control circuit of the cooking device according to claim 6, characterized in that: The voltage doubling circuit comprises: a first diode, wherein a cathode of the first diode is connected to a second end of the fourth inductor; a second diode, wherein an anode of the second diode is connected to a cathode of the first diode; a third capacitor, wherein a first end of the third capacitor is connected to the anode of the first diode, and a second end of the third capacitor is connected to the second end of the third inductor; A fourth capacitor, wherein a first end of the fourth capacitor is connected to the second end of the third capacitor, and a second end of the fourth capacitor is connected to the cathode of the second diode.
8. The driving control circuit of the cooking device according to claim 7, characterized in that: The driving control circuit of the cooking device also includes: A first resistor, wherein a first end of the first resistor is connected to a first end of the third capacitor, and a first end of the first resistor is connected to a second end of the fourth capacitor.
9. A cooking device, characterized in that: include: The variable frequency power supply according to any one of claims 1 to 4; or A driving control circuit for a cooking device as claimed in any one of claims 5 to 8.
10. The cooking device according to claim 9, characterized in that The cooking device includes a microwave oven or a microwave oven.