CN203801099U - Power circuit and microwave oven - Google Patents

Abstract

The utility model provides a power circuit and a microwave oven. The power circuit comprises: a frequency conversion circuit, which is connected to a voltage inverter circuit and is used for converting an external direct current into an alternating current and changing the frequency of the alternating current; the voltage inverter circuit, which is connected to a voltage doubling circuit and is used for receiving the alternating current from the frequency conversion circuit and outputting the alternating current to the voltage doubling circuit; and the voltage doubling circuit, which is connected to a magnetron in a heater and is used for boosting the voltage of the alternating current to drive the magnetron. According to the power circuit, the voltage doubling circuit is used for completing boosting processing of a load voltage; and the circuit has the simple structure.

Description

Power Circuits and Microwave Ovens

technical field

The utility model relates to the technical field of microwave heating, in particular to a power circuit and a microwave oven with the power circuit.

Background technique

On the power supply of the high-frequency heating equipment of the frequency conversion microwave oven, in order to drive the magnetron to output microwaves, the voltage of 220 volts of the mains needs to be boosted by more than 20 times to supply power for the magnetron.

The traditional boosting method is to change the output voltage by changing the ratio of the number of wires between the primary coil and the secondary coil of the transformer. If a higher voltage is required, the number of wires is relatively large. This boosting method has limitations, so a The new power supply circuit uses a new boost method to increase the mains voltage to drive the magnetron.

Utility model content

The utility model aims at at least solving one of the technical problems existing in the prior art or the related art.

Therefore, an object of the present utility model is to provide a power supply circuit, which can raise the mains voltage to the voltage required for driving the magnetron without changing the transformer ratio.

Another object of the utility model is to provide a microwave oven.

In order to achieve the above object, according to the embodiment of the first aspect of the present invention, a power supply circuit is provided for a heater, including: a frequency conversion circuit connected to a voltage inverter circuit to convert external DC power into AC power and changing the frequency of the alternating current; the voltage inverter circuit is connected to the voltage doubler circuit, receives the alternating current from the frequency conversion circuit, and transmits the alternating current to the voltage doubler circuit; the voltage doubler circuit is connected to The magnetron in the heater increases the voltage of the alternating current to drive the magnetron.

The external direct current may be direct current output after rectifying the mains power, so the rectification filter may not be integrated in the power supply circuit. In this embodiment, a voltage doubler circuit is connected after the voltage inverter circuit, and the voltage inverter circuit is not only used to transmit electric energy, but also used to increase the voltage of the alternating current, but the voltage of the alternating current is not sufficient for driving The magnetron uses the increased voltage doubler circuit to continue to increase the voltage of the alternating current, thereby driving the magnetron to output microwaves. The structure of the power supply circuit is different from the current way of only using the voltage inverter circuit to boost the voltage, and the circuit structure Simple, just add a voltage doubler circuit.

In the above technical solution, preferably, the voltage doubling circuit is a half-wave voltage doubling circuit. Those skilled in the art should understand that the voltage doubling circuit may also be a full-wave voltage doubling circuit.

In the above technical solution, preferably, the voltage inverter circuit is a transformer, and the voltage doubler circuit includes: a capacitor and a first diode, the capacitor is connected to the first diode, and the transformer Two ends of the first secondary coil are respectively connected to the capacitor and the first diode.

In the above technical solution, preferably, one end of the capacitor is connected to one end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the anode of the first diode; the first diode The cathode of the tube is connected to the other end of the first secondary coil and the magnetron and grounded, and the anode of the first diode is connected to one end of the second secondary coil of the transformer, wherein the Both ends of the second secondary coil of the transformer are connected to the magnetron.

In the above technical solution, preferably, one end of the capacitor is connected to one end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the negative pole of the first diode and grounded; the first The cathode of the diode is also connected to the magnetron, the anode of the first diode is connected to the other end of the first secondary coil and one end of the second secondary coil of the transformer, wherein, Both ends of the second secondary coil of the transformer are connected to the magnetron.

In the above technical solution, preferably, the voltage doubling circuit may further include: a second diode connected in series with the first diode.

In the above technical solution, preferably, one end of the capacitor is connected to the first end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the cathode of the first diode and grounded; The positive pole of the first diode is connected to the negative pole of the second diode, and the positive pole of the second diode is also connected to the magnetron; the negative pole of the second diode is connected to The other end of the first secondary coil, the anode of the second diode is connected to one end of the second secondary coil of the transformer, wherein both ends of the second secondary coil are connected to the described magnetron.

In this embodiment, the voltage doubling circuit includes a high-voltage capacitor and two high-voltage diodes. When the anode voltage of the first diode is higher than the cathode voltage, the first diode is turned on, and the transformer supplies power to the transformer through the first diode. The capacitor is charged, and the magnetron does not work at this time; otherwise, the transformer and the capacitor are connected in series to form a voltage doubler circuit, the first diode is disconnected, the second diode is turned on, and the voltage passes through the magnetron and the second diode The tube forms a loop, and the secondary voltage can be stabilized at 4000 volts to drive the magnetron to work normally by using the voltage stabilization and unidirectional conduction characteristics of the magnetron itself.

In the above technical solution, preferably, one end of the capacitor is connected to the first end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the anode of the first diode; The anode of the second diode is connected to the cathode of the first diode, the cathode of the second diode is connected to the magnetron and grounded; the cathode of the first diode is connected to the first diode The other end of the primary coil, the anode of the first diode is also connected to one end of the second secondary coil of the transformer, wherein both ends of the second secondary coil are connected to the magnetic control. In this embodiment, the voltage doubling circuit includes a capacitor and a diode, which can also realize the voltage doubling function. Such a voltage doubling circuit uses fewer components, occupies a smaller volume, and reduces the cost accordingly.

In the above technical solution, preferably, it may further include: a rectification circuit connected to the frequency conversion circuit, converting external AC power into DC power, and outputting the DC power to the frequency conversion circuit.

In the above technical solution, preferably, the frequency conversion circuit includes: a switch circuit connected to the drive circuit, receiving the direct current, and turning on or off the primary circuit of the power supply circuit according to the drive signal of the drive circuit; The driving circuit is connected to a controller, receives a control signal from the controller, and converts the control signal into the driving signal; the controller sends the control signal to the driving circuit. Wherein, the switch circuit is a power switch device.

According to an embodiment of the second aspect of the present invention, there is also provided a microwave oven, including the power supply circuit described in any one of the above technical solutions.

Because the power supply circuit according to the utility model has a simple structure and a small volume, the volume of the microwave oven using the above power supply circuit is also relatively small.

Description of drawings

Fig. 1 shows a schematic structural diagram of a power supply circuit according to an embodiment of the present invention;

Fig. 2 shows a schematic structural diagram of a power supply circuit according to another embodiment of the present invention;

FIG. 3A shows a schematic diagram of one of the working modes of the power supply circuit shown in FIG. 2;

FIG. 3B shows a schematic diagram of another working mode of the power supply circuit shown in FIG. 2;

Fig. 4 shows a schematic structural diagram of a power supply circuit according to another embodiment of the present invention;

FIG. 5A shows a schematic diagram of one of the working modes of the power supply circuit shown in FIG. 4;

FIG. 5B shows a schematic diagram of another working mode of the power supply circuit shown in FIG. 4;

FIG. 6 shows a schematic structural diagram of a power supply circuit according to another embodiment of the present invention;

FIG. 7A shows a schematic diagram of one of the working modes of the power supply circuit shown in FIG. 6;

FIG. 7B shows a schematic diagram of another working mode of the power supply circuit shown in FIG. 6;

Fig. 8 shows a schematic structural diagram of a power supply circuit according to yet another embodiment of the present invention;

FIG. 9A shows a schematic diagram of one of the working modes of the power supply circuit shown in FIG. 8;

FIG. 9B shows a schematic diagram of another working mode of the power supply circuit shown in FIG. 8 .

Detailed ways

In order to more clearly understand the above purpose, features and advantages of the utility model, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

In the following description, a lot of specific details have been set forth in order to fully understand the utility model, but the utility model can also be implemented in other ways that are different from those described here. Therefore, the utility model is not limited to the specific details disclosed below. EXAMPLE LIMITATIONS.

Fig. 1 shows a schematic structural diagram of a power supply circuit according to an embodiment of the present invention.

As shown in Figure 1, according to the embodiment of the first aspect of the present invention, a power supply circuit is provided for a heater, including: a frequency conversion circuit 104, connected to a voltage inverter circuit 106, which converts the DC power from the outside become alternating current and change the frequency of the alternating current; the voltage inverter circuit 106 is connected to the voltage doubler circuit 108, receives the alternating current from the frequency conversion circuit, and transmits the alternating current to the voltage doubler circuit 108; The voltage doubling circuit 108 is connected to the magnetron 110 in the heater, and increases the voltage of the alternating current to drive the magnetron 110 .

The external direct current may be direct current output after rectifying the mains power, so the rectification filter may not be integrated in the power supply circuit. In this embodiment, a voltage doubler circuit is connected after the voltage inverter circuit, and the voltage inverter circuit is not only used to transmit electric energy, but also used to increase the voltage of the alternating current, but the voltage of the alternating current is not sufficient for driving The magnetron uses the increased voltage doubler circuit to continue to increase the voltage of the alternating current, thereby driving the magnetron to output microwaves. The structure of the power supply circuit is different from the current way of only using the voltage inverter circuit to boost the voltage, and the circuit structure Simple, just add a voltage doubler circuit.

In the above technical solution, preferably, the voltage doubling circuit 108 is a half-wave voltage doubling circuit. Those skilled in the art should understand that the voltage doubling circuit may also be a full-wave voltage doubling circuit.

In the above technical solution, preferably, the voltage inverter circuit 106 is a transformer, as shown in Figure 2, the voltage doubler circuit 108 includes: a capacitor, a first diode and a second diode, the capacitor Connected to the first diode, the first diode is connected in series with the second diode, and the two ends of the first secondary coil of the transformer are respectively connected to the capacitor and the first diode.

In the above technical solution, preferably, as shown in FIG. 3A and FIG. 3B , the voltage doubler circuit 108 includes: a capacitor (namely capacitor C1), one end of the capacitor is connected to the first secondary coil of the transformer The first end, the other end of the capacitor is connected to the cathode of the first diode (ie diode D1) and grounded; the first diode, the anode of the first diode is connected to the second diode tube (i.e. diode D2), the anode of the second diode is also connected to the magnetron; the second diode, the cathode of the second diode is connected to the first The other end of the secondary coil, the anode of the second diode is connected to one end of the second secondary coil of the transformer, wherein both ends of the second secondary coil are connected to the magnetron 110.

In this embodiment, the voltage doubler output circuit includes two high-voltage diodes and a high-voltage capacitor. One end of the secondary side of the high-voltage transformer is connected to the high-voltage capacitor; the other end of the secondary side of the transformer is connected to two high-voltage diodes; connected and connected to the ground; the anode of the second diode is connected to the filament winding on the magnetron.

When the variable frequency power supply is working, the power switching device 1042 is turned on and off according to the power control information; the capacitor C17 and the primary coil of the transformer T1 form a resonant loop, and the current presents positive and negative directions at different times in the resonant loop, and then T1 The secondary side will generate different positive and negative voltages. When terminal 4 of T1 is forward voltage, the voltage of the positive pole of diode D1 is higher than the voltage of the negative pole, the diode D1 is turned on, and the transformer T1 charges the capacitor C1 through the diode D1, as shown in Figure 3A, the magnetron does not work at this time; when When terminal 3 of T1 is forward voltage, the voltage of transformer T1 and capacitor C1 are connected in series to form a voltage doubler circuit, diode D1 is disconnected, diode D2 is turned on, and the voltage forms a loop through the magnetron and diode D2, see Figure 3B, use The magnetron itself has voltage stabilization and one-way conduction characteristics, and the secondary voltage can be stabilized at 4000 volts to drive the magnetron to work normally.

In the above technical solution, preferably, as shown in Fig. 4, Fig. 5A and Fig. 5B, the voltage inverter circuit 106 is a transformer, and the voltage doubling circuit 108 includes: a capacitor (namely capacitor C1), the One end is connected to the first end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the anode of the first diode; the second diode (ie diode D1), the second The anode of the diode is connected to the cathode of the first diode, and the cathode of the second diode is also connected to the magnetron 110 and ground; the first diode (that is, the diode D2), the The cathode of the first diode is connected to the other end of the first secondary coil, and the anode of the first diode is also connected to one end of the second secondary coil of the transformer, wherein the first Both ends of the secondary coil are connected to the magnetron 110 . When working, when the 4 terminals of T1 are negative voltage, the voltage of the positive pole of D2 is higher than the voltage of the negative pole, D2 is turned on, and the transformer T1 charges C2 through D2, see Figure 5A, at this time the magnetron does not work; when T1 When the 4 terminals of the transformer are positive voltage, D1 is turned on, the voltage of transformer T1 is connected in series with C2 to form a voltage doubler circuit, and the voltage is output to the magnetron through D1, see Figure 5B, and the magnetron itself is used for voltage stabilization and unidirectional conduction Features, the secondary voltage can be stabilized at 4000 volts, driving the magnetron to work normally.

In the above technical solution, preferably, the voltage doubler circuit 108 includes: a capacitor and a first diode, the capacitor is connected to the first diode, and the two ends of the first secondary coil of the transformer respectively connected to the capacitor and the first diode

Wherein, preferably, as shown in FIG. 6 , FIG. 7A and FIG. 7B , the voltage doubler circuit 108 includes: a capacitor (namely C1), one end of the capacitor is connected to one end of the first secondary coil of the transformer, The other end of the capacitor is connected to the anode of the first diode; the first diode (namely diode D1), the cathode of the first diode is connected to the other end of the first secondary coil And the magnetron 110 is grounded, the anode of the first diode is connected to one end of the second secondary coil of the transformer, wherein both ends of the second secondary coil of the transformer are connected to The magnetron 110 . In this embodiment, the voltage doubling circuit includes a capacitor and a diode, which can also realize the voltage doubling function. Such a voltage doubling circuit uses fewer components, occupies a smaller volume, and reduces the cost accordingly.

During operation, when terminal 3 of T1 is a forward voltage, the voltage of the positive pole of D2 is higher than the voltage of the negative pole, D2 is turned on, and the transformer T1 charges C2 through D2, as shown in Figure 7A, at this time the magnetron 110 does not work; when When terminal 4 of T1 is forward voltage, the voltage of transformer T1 is connected in series with C2 to form a voltage doubler circuit, and the voltage is output to the magnetron 110, see Fig. 7B, using the voltage stabilization and unidirectional conduction characteristics of the magnetron itself, the secondary The voltage can be stabilized at 4000 volts to drive the magnetron 110 to work normally.

In the above technical solution, preferably, as shown in FIG. 8, FIG. 9A and FIG. 9B, the voltage doubler circuit 108 includes: a capacitor (that is, capacitor C1), one end of the capacitor is connected to the first One end of the primary coil, the other end of the capacitor is connected to the cathode of the first diode and grounded; the first diode (i.e. diode D2), the cathode of the first diode is also connected to the Magnetron 110, the anode of the first diode is connected to the other end of the first secondary coil and one end of the second secondary coil of the transformer, wherein the second secondary coil of the transformer Both ends of are connected to the magnetron 110.

When working, when the 4 terminals of T1 are positive voltage, the voltage of the positive pole of D1 is higher than the voltage of the negative pole, D1 is turned on, and the transformer T1 charges C1 through D1, as shown in Figure 9A, at this time the magnetron 110 does not work; when When terminal 3 of T1 is a forward voltage, the voltage of transformer T1 is connected in series with C1 to form a voltage doubling circuit, and the voltage is output to the magnetron 110, as shown in Fig. 9B. The stage voltage can be stabilized at 4000 volts to drive the magnetron 110 to work normally.

In the above technical solution, preferably, continuing to return to Fig. 1 and Fig. 2, the power supply circuit may further include: a rectifier circuit 102, connected to the frequency conversion circuit 104, converting the alternating current from the outside into direct current, and converting the direct current output to the frequency conversion circuit 104.

In the above technical solution, preferably, returning to FIG. 2 , as shown in FIG. 2 , the frequency conversion circuit 104 includes: a switch circuit 1042 connected to the drive circuit 1044, receiving the direct current, and according to the driving circuit of the drive circuit The signal turns on or off the primary loop of the power supply circuit; the drive circuit 1044 is connected to the controller 1046, receives a control signal from the controller, and converts the control signal into the drive signal; The controller 1046 sends the control signal to the drive circuit 1044. Wherein, the switch circuit 1042 is a power switch device.

According to the power supply circuit of the present invention, a new voltage boosting method is provided, and a voltage doubler circuit is added, wherein, preferably, the voltage doubler circuit is a half-wave voltage doubler circuit, the circuit structure is simple, and high-voltage devices (high-voltage capacitors and high-voltage The number of diodes) is relatively small. On the premise of satisfying the electrical clearance and creepage distance, the circuit board size can be smaller, so that the entire power module is smaller, more versatile, and lower in cost.

According to an embodiment of the second aspect of the present invention, there is also provided a microwave oven, including the power supply circuit described in any one of the above technical solutions.

Because the power supply circuit according to the utility model has a simple structure and a small volume, the volume of the microwave oven using the above power supply circuit is also relatively small.

The above descriptions are only preferred embodiments of the utility model, and are not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present utility model shall be included in the protection scope of the present utility model.

Claims (11)

1. A power circuit, characterized in that it is used for a heater, comprising: A frequency conversion circuit, connected to the voltage inverter circuit, converts the direct current from the outside into alternating current and changes the frequency of the alternating current; The voltage inverter circuit is connected to the voltage doubling circuit, receives the alternating current from the frequency conversion circuit, and transmits the alternating current to the voltage doubling circuit; The voltage doubling circuit is connected to the magnetron in the heater, and boosts the voltage of the alternating current to drive the magnetron. 2. The power supply circuit according to claim 1, wherein the voltage doubling circuit is a half-wave voltage doubling circuit. 3. The power supply circuit according to claim 1, wherein the voltage inverter circuit is a transformer, and the voltage doubler circuit includes: a capacitor and a first diode, and the capacitor and the first diode The two ends of the first secondary coil of the transformer are respectively connected to the capacitor and the first diode. 4. The power supply circuit according to claim 3, wherein one end of the capacitor is connected to one end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the anode of the first diode ; The cathode of the first diode is connected to the other end of the first secondary coil and the magnetron and grounded, and the anode of the first diode is connected to the second secondary coil of the transformer , wherein both ends of the second secondary coil of the transformer are connected to the magnetron. 5. The power supply circuit according to claim 3, wherein one end of the capacitor is connected to one end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the negative pole of the first diode and ground; The cathode of the first diode is also connected to the magnetron, and the anode of the first diode is connected to the other end of the first secondary coil and the second secondary coil of the transformer. One end, wherein both ends of the second secondary coil of the transformer are connected to the magnetron. 6. The power supply circuit according to claim 3, wherein the voltage doubling circuit further comprises: a second diode connected in series with the first diode. 7. The power supply circuit according to claim 6, wherein one end of the capacitor is connected to the first end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the first two The negative pole of the pole tube is grounded; The anode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is also connected to the magnetron; The cathode of the second diode is connected to the other end of the first secondary coil, and the anode of the second diode is connected to one end of the second secondary coil of the transformer, wherein the first Both ends of the secondary secondary coil are connected to the magnetron. 8. The power supply circuit according to claim 6, wherein one end of the capacitor is connected to the first end of the first secondary coil of the transformer, and the other end of the capacitor is connected to the first two positive pole of the pole tube; The anode of the second diode is connected to the cathode of the first diode, and the cathode of the second diode is connected to the magnetron and grounded; The cathode of the first diode is connected to the other end of the first secondary coil, and the anode of the first diode is also connected to one end of the second secondary coil of the transformer, wherein the Both ends of the second secondary coil are connected to the magnetron. 9. The power supply circuit according to any one of claims 1 to 8, further comprising: The rectifier circuit is connected to the frequency conversion circuit, converts the external AC power into DC power, and outputs the DC power to the frequency conversion circuit. 10. The power supply circuit according to claim 9, wherein the frequency conversion circuit comprises: A switch circuit, connected to the drive circuit, receives the direct current, and turns on or off the primary circuit of the power supply circuit according to a drive signal of the drive circuit; The driving circuit is connected to a controller, receives a control signal from the controller, and converts the control signal into the driving signal; The controller sends the control signal to the drive circuit. 11. A microwave oven, characterized by comprising the power circuit according to any one of claims 1-10.