Patent Application
20190131786
The present disclosure relates to a household appliance field, and more particularly to a surge suppression circuit and a microwave oven.
In the related art of the inverter microwave oven, when a surge voltage exists in a circuit supplying power to a magnetron, the surge voltage may be increased by a reverse voltage generated by an inductor of a filtering device, and thus a rectifying device may be broken down by the overvoltage and the circuit may be damaged.
Embodiments of the present disclosure seek to solve at least one of the problems existing in the related art to at least some extent. Accordingly, embodiments of the present disclosure provide a surge suppression circuit and a microwave oven.
The surge suppression circuit includes:
a rectifying device including
a filtering device coupled to the rectifying output part; and
a protection element disposed on the rectifying output part and coupled to the filtering device, and configured to suppress an overvoltage of the rectifying output part when a surge occurs.
In the surge suppression circuit described above, the protection element is able to suppress the overvoltage of the rectifying output part when a surge occurs, thus improving a circuit reliability of the rectifying device and the entire microwave oven.
In some embodiments, the rectifying output part includes two rectifying output terminals; the filtering device includes:
In some embodiments, the protection element is a second capacitor.
In some embodiments, the protection element is a discharge tube.
In some embodiments, the rectifying output part includes two rectifying output terminals, and the protection element is coupled in parallel with the two rectifying output terminals.
In some embodiments, the protection element is a capacitor.
In some embodiments, the protection element is a discharge tube.
In some embodiments, the surge suppression circuit further includes:
an inverter device coupled to the filtering device and configured to convert a direct current output from the filtering device into an alternating current, and
a voltage doubler rectifying device coupled to the inverter device and configured to boost and covert the alternating current output from the inverter device into a high voltage direct current and supply a power.
In some embodiments, the inverter device includes a capacitor, an insulated gate bipolar transistor (IGBT) and a transformer, in which
two terminals of the capacitor are coupled to two primary winding terminals of the transformer to form a resonant circuit, and a secondary winding terminal of the transformer is coupled to the voltage doubler rectifying device;
a first terminal of the capacitor is coupled to a collector of the IGBT and a second terminal of the capacitor is coupled to the filtering device, and an emitter of the IGBT is coupled to the filtering device via a resistor;
the IGBT is configured to control the resonant circuit to generate a high frequency alternating current.
A microwave oven is provided, including a surge suppression circuit according to any of above embodiments.
The surge suppression circuit 100 is provided in the microwave oven described above.
The protection element in the surge suppression circuit can suppress the overvoltage of the rectifying output part caused by the surge, thus improving the circuit reliability of the rectifying device 10 and the entire microwave oven, and also improving the anti-surge capability and the reliability of the whole machine.
Embodiments of the present disclosure are described in detail below, examples of which are illustrated in the drawings. The same or similar elements are denoted by same reference numerals in different drawings unless indicated otherwise. The embodiments described herein with reference to drawings are explanatory, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure.
In the present disclosure, it should be understood that terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply a relative importance or an amount of a feature. Thus, the feature defined with “first” and “second” may include one or more this feature. In the description of the present disclosure, unless specified otherwise, “a plurality of” means two or more than two.
In the present disclosure, unless specified or limited otherwise, the terms “mounted”, “connected”, “coupled” and the like are used broadly, and may be, for example, fixed connections, detachable connections, or integral connections; may also be mechanical or electrical connections; may also be direct connections or indirect connections via intervening structures; may also be inner communications of two elements.
Various embodiments and examples are provided in the following description to implement different structures of the present disclosure. In order to simplify the present disclosure, certain elements and settings will be described. However, these elements and settings are only by way of example and are not intended to limit the present disclosure. In addition, reference numerals may be repeated in different examples in the present disclosure. This repeating is for the purpose of simplification and clarity and does not refer to relations between different embodiments and/or settings. Furthermore, examples of different processes and materials are provided in the present disclosure. In other embodiments, other processes and/or materials may be also applied.
With reference to
The surge suppression circuit 100 may be used as a switching device to supply power to a magnetron of an inverter microwave oven. When the switching device is turned on, a strong pulse, i.e., an overvoltage exceeding a normal voltage, is generated. Such an overvoltage will cause damage to electronic components in the circuit.
The rectifying device 10 includes a rectifying input part and a rectifying output part. The rectifying input part is coupled to a voltage input terminal and configured to convert an input electric supply (i.e., an alternating current AC) into a direct current (DC). The filtering device 20 is coupled to the rectifying output part. Usually, the AC may still exist after rectification, and thus the filtering device 20 is configured to filter the rectified current to obtain a relatively pure DC. The protection element 30 is disposed on the rectifying output part and coupled to the filtering device 20, and configured to suppress an overvoltage of the rectifying output part when a surge occurs.
In the surge suppression circuit 100 described above, the overvoltage of the rectifying output part may be suppressed by the protection element 30 when the surge occurs, thereby improving a circuit reliability of the rectifying device 10 and the entire microwave oven.
In one embodiment, the rectifying device 10 includes a bridge rectifier 12. Pins 12b and 12c of the bridge rectifier are coupled to the voltage input terminal, that is, to the rectifying input part of the rectifying device 10, and pins 12a and 12d are coupled to the filtering device 20, that is, to the rectifying output part of the rectifying device 10. The pins 12a and 12d may be served as two rectifying output terminals.
In some embodiments, with reference to
The direct current output from the rectifying device 10 is not a pure direct current and still contains an alternating current part. It is known that an inductive element may be used to pass a direct current and block an alternating current. The alternating current part may be filtered by the inductor 22. However, since the inductance 22 has a limited ability to block the alternating current, a first capacitor 24 is further used for filtering the alternative current after the inductor 22 due to a capacitor nature of passing an alternating current and blocking a direct current. The alternative current may be bypassed to the ground by the first capacitor 24. On this basis, a relative pure direct current may be obtained. In addition, the inductor 22 is also configured to suppress differential mode interference between power lines when the system is powered on.
Since a reverse induced voltage may be generated by the inductor 22, an addition of the reverse voltage and the surge voltage may increase the overvoltage, such that the reverse voltage of the rectifying output part of the rectifying device 10 may be very high, thus damaging the rectifying device 10. The protection element 30 is provided on the rectifying output part of the rectifying device 10 to effectively suppress the reverse voltage to improve the reliability of the rectifying device 10.
With reference to
With reference to
With reference to
With reference to
In addition, the protection element 30 may also be a transient voltage suppressor (TVS). Similar to the capacitor and the discharge tube, the TVS may be configured to absorb a large current in an instant and clamp the terminal voltage to a predetermined value, thus avoiding damages to a protected component due to a transient high-energy impact.
With reference to
In one embodiment, in some embodiments, with reference to
A first terminal of the fourth capacitor 42 is coupled to a collector of the IGBT 44 and a second terminal of the fourth capacitor 42 is coupled to the filtering device 20, and an emitter of the IGBT 44 is coupled to the filtering device 20 via a resistor 60.
The IGBT 44 is served as a switch to control a resonant circuit. When a direct current is input to the IGBT 44, the current may be conducted or not conducted according to the required alternating frequency, such that the direct current is divided according to the required frequency, thus converting the direct current into the alternating current. Moreover, the alternating current frequency is usually required to be high, that is, the IGBT 44 is configured to control the resonant circuit to generate a high frequency alternating current. The high frequency alternating current is output from the primary level to the secondary level of the transformer.
It should be understood that, in the circuit shown in
The microwave oven according to an embodiment of the present disclosure includes the surge suppression circuit 100 of any of the above embodiments.
Therefore, the protection element 30 in the surge suppression circuit 100 provided in the microwave oven can suppress the overvoltage of the rectifying output part caused by the surge, thus improving the circuit reliability of the rectifying device 10 and the entire microwave oven, and also improving the anti-surge capability and the reliability of the whole machine.
In one embodiment, the microwave oven is an inverter microwave oven. The house current with a frequency of 50 Hz may be converted to a high frequency output current by the surge suppression circuit 100 as described above, such that an output power may be controlled by the inverter microwave oven during a heating process and a heating efficiency is improved.
Reference throughout this specification to “an embodiment”, “some embodiments”, “a schematic embodiment”, “an example”, “a specific example” or “some examples” means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. Thus, the appearances of the above phrases in various places throughout this specification are not necessarily referring to the same embodiment or example of the present disclosure. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
In addition, terms such as “first” and “second” are used herein for purposes of description and are not intended to indicate or imply a relative importance or an amount of a feature. Thus, the feature defined with “first” and “second” may include one or more this feature. In the description of the present disclosure, unless specified otherwise, “a plurality of” means at least two, for example, two or three.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201610196929.5 | Mar 2016 | CN | national |
| 201620262277.6 | Mar 2016 | CN | national |
This application is a continuation of International Application No. PCT/CN2016/086389, filed Jun. 20, 2016, which claims a priority to and benefits of Chinese Patent Application Serial No. 201610196929.5 and 201620262277.6, filed with the State Intellectual Property Office of P. R. China on Mar. 30, 2016, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2016/086389 | Jun 2016 | US |
| Child | 16172730 | US |
