Circuit for eliminating inverter freeze, refrigerator and control method thereof

Abstract

The present invention proposes a circuit, a refrigerator and a control method thereof for eliminating inverter freezes, and belongs to the technical field of household appliances. The circuit includes a main control board, an MCU, a PWM detection circuit and a DC-DC circuit for providing power to the MCU; the main control board sends a PWM signal, and the output end of the PWM signal is divided into two paths, one of which is connected to the MCU, and the MCU is used to control the operation of the inverter according to the PWM signal; the other path is connected to the input end of the PWM detection circuit, and the output end of the PWM detection circuit is connected to the control end of the DC-DC circuit, which is used to control the power output of the DC-DC circuit to the MCU; wherein the PWM detection circuit is turned on and controls the DC-DC circuit to output power when there is a PWM signal input, so as to power on the MCU; the PWM detection circuit is not turned on when there is no PWM signal input, so that the DC-DC circuit has no power output, so as to power off the MCU. The present invention can solve the inverter freeze caused by program runaway and voltage latching without changing the interface between the inverter and the main control board, and the implementation method is simple, low cost, and can reduce standby power consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of household appliances, and in particular to a circuit for eliminating inverter freeze, a refrigerator and a control method thereof. Background Art

[0002] With the increasing requirements for refrigerator energy efficiency and refrigerator refrigeration and preservation capabilities, inverters are increasingly used in refrigerators. The inverter is a pulse-controlled power component that generates a lot of interference. Coupled with various interferences from the user's power environment, the control chip will cause program runaway and voltage latching and other crashes. For refrigerators, once the inverter crashes, it will not only affect the quality of the user's stored food, but in serious cases, it may also be dangerous. At the same time, the cost of after-sales service will also increase. Summary of the invention

[0003] The present invention solves one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the present disclosure aims to provide a circuit, a refrigerator and a control method thereof for eliminating inverter freezes, realizing power-on reset of the MCU without changing the interface between the inverter and the main control board, solving inverter freezes caused by program runaway and voltage latching, etc. The implementation method is simple, low-cost and can reduce standby power consumption.

[0005] A circuit for eliminating inverter freeze in one aspect of the present disclosure includes: a main control board, an MCU, a PWM detection circuit, and a DC-DC circuit for providing power to the MCU; the main control board sends a PWM signal, and the output end of the PWM signal is divided into two paths, one of which is connected to the MCU, and the MCU is used to control the operation of the inverter according to the PWM signal; the other path is connected to the input end of the PWM detection circuit, and the output end of the PWM detection circuit is connected to the control end of the DC-DC circuit, which is used to control the power output of the DC-DC circuit to the MCU;

[0006] Among them, the PWM detection circuit is turned on and controls the DC-DC circuit to output power when a PWM signal is input, so as to power on the MCU; the PWM detection circuit is not turned on when no PWM signal is input, so that the DC-DC circuit has no power output, so as to power off the MCU.

[0007] According to an embodiment of the circuit for eliminating inverter freeze in the present disclosure, when the main control board detects that the inverter freezes, it first stops sending the PWM signal and then resends it, and the PWM detection circuit controls the DC-DC circuit to first power off the MCU and then power it on to reset it to exit the freeze state.

[0008] According to an embodiment of the circuit for eliminating inverter freeze disclosed in the present invention, the PWM detection circuit is a multi-stage amplifier circuit.

[0009] According to the embodiment of the circuit for eliminating inverter freeze disclosed in the present invention, the multi-stage amplification circuit includes: a first-stage amplification circuit and a second-stage amplification circuit connected to the output end of the first-stage amplification circuit; the first-stage amplification circuit includes an NPN transistor V32, a DC power supply VCC, a resistor R33 and a resistor R28;

[0010] The input end of the first-stage amplifier circuit is connected to the base of the transistor V32 through a capacitor C31 and a resistor R34 connected in series, the collector of the transistor V32 is connected to the DC power supply VCC through resistors R36 and R35 connected in series in sequence, and the emitter of the transistor V32 is grounded; one end of the resistor R33 is connected to the DC power supply VCC, and the other end is connected between the capacitor C31 and the resistor R34; one end of the resistor R28 is connected between the resistor R34 and the base of the transistor V32, and the other end is grounded;

[0011] The secondary amplifier circuit includes a PNP transistor V31, the base of the transistor V31 is connected between the resistor R36 and the resistor R35, the emitter of the transistor V31 is connected to the DC power supply VCC, and the collector of the transistor V31 is connected in series with a resistor R37 and then divided into three paths, one of which is grounded through a capacitor C32, one is grounded through a resistor R38, and one is connected to the control end of the DC-DC circuit.

[0012] According to an embodiment of the circuit for eliminating inverter freeze disclosed in the present invention, a voltage regulator tube is connected in parallel between the two ends of the resistor R38.

[0013] A refrigerator according to another aspect of the present disclosure includes the above-mentioned circuit for eliminating inverter freeze.

[0014] A refrigerator control method according to another aspect of the present invention comprises the following steps: when the main control board detects that the inverter is frozen, it stops sending PWM signals, the PWM detection circuit is turned off to control the DC-DC circuit to have no power output, and the MCU is powered off; after a first preset time period, the main control board resends the PWM signal, the PWM detection circuit is turned on to control the DC-DC circuit to output power, the MCU is powered on and reset, and exits the frozen state.

[0015] According to an embodiment of the control method of the refrigerator disclosed in the present invention, the step of detecting that the inverter is dead includes: detecting that the compressor is in operation, the evaporator temperature does not drop, and the operation exceeds a second preset time.

[0016] According to an embodiment of the control method of the refrigerator disclosed in the present invention, the main control board resends the PWM signal after a first preset time period to clear the timer.

[0017] Beneficial Effects

[0018] According to the present disclosure, a PWM detection circuit is connected to the PWM signal output end, and the output end of the PWM detection circuit is connected to the control end of the DC-DC circuit. The PWM detection circuit is turned on when a PWM signal is input to control the DC-DC circuit to power on the MCU, and is not turned on when no PWM signal is input to control the DC-DC circuit to power off the MCU. When the inverter crashes, the PWM detection circuit can control the DC-DC circuit to first power off the MCU and then power it on again, so that it exits the crash state. The circuit of the present disclosure can solve the crash caused by program running away and voltage latching without changing the interface between the inverter and the main control board. The implementation method is simple, the cost is low, and the standby power consumption can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of an MCU and a DC-DC circuit in the prior art;

[0021] Figure 2 It is an application block diagram of a circuit for eliminating inverter freeze according to an embodiment of the present disclosure;

[0022] Figure 3 It is a principle diagram of a circuit for eliminating inverter freeze according to an embodiment of the present disclosure;

[0023] Figure 4 yes Figure 3 Schematic diagram of the PWM detection circuit;

[0024] Figure 5 is a flow chart of a method for controlling a refrigerator according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0025] The present invention is described in detail below by way of exemplary embodiments. However, it should be understood that elements, structures, and features in one embodiment may also be beneficially combined in other embodiments without further description.

[0026] Figure 1 It is a schematic diagram of MCU connection in the prior art.

[0027] Reference Figure 1The PWM signal is input to the MCU to control the start and stop and speed of the inverter, and the DC-DC circuit provides power for the MCU; the control end of the DC-DC circuit is directly connected to 15V, and as long as there is a 15V power supply, the DC-DC circuit will provide 5V power to the MCU.

[0028] In the prior art, once the inverter of the refrigerator crashes, it will not only affect the quality of the food stored by the user, but also cause danger in serious cases. The inverter of the refrigerator basically controls the start and stop and the operating frequency of the inverter by inputting PWM pulses. Considering the compatibility and universality issues, the inverter control is inconvenient to change. Therefore, one aspect of the present disclosure provides a circuit for eliminating the inverter crash without changing the interface between the inverter and the main control board.

[0029] Figure 2 The present invention is an application block diagram of a circuit for eliminating inverter freeze according to an embodiment of the present invention.

[0030] Reference Figure 2 The circuit for eliminating inverter freeze includes: main control board, MCU, PWM detection circuit and DC-DC circuit.

[0031] The main control board sends out a PWM signal, which is divided into two paths. One path is input to the MCU to control the start and stop and speed of the inverter, and the other path is input to the PWM detection circuit. The output end of the PWM detection circuit is connected to the control end of the DC-DC circuit. The PWM detection circuit can control the power on or off of the MCU by controlling the DC-DC circuit.

[0032] Specifically, when there is a PWM signal input, the PWM detection circuit is turned on, controls the DC-DC circuit to output power, and powers on the MCU. When there is no PWM signal input, the PWM detection circuit is not turned on, the DC-DC circuit has no power output, and the MCU is powered off. Thus, the PWM detection circuit controls the MCU by controlling the power output of the DC-DC circuit. When the inverter freezes, the PWM detection circuit can first control the MCU to power off and then power on again to reset, so that the inverter status returns to normal and the freeze is eliminated.

[0033] The circuit for eliminating inverter freezes disclosed in the present invention can eliminate the freeze by setting a PWM detection circuit for controlling a DC-DC circuit. After the inverter freezes, the MCU can be powered off and then powered on again for reset, thereby eliminating the freeze. The circuit disclosed in the present invention can solve the freezes caused by program runaway and voltage latching without changing the interface between the inverter and the main control board. The implementation method is simple, the cost is low, and the standby power consumption can be reduced.

[0034] Specifically, when the main control board detects that the inverter is not working, it stops sending the PWM signal for two minutes and then sends it again. In this way, the PWM detection circuit is not turned on when there is no PWM signal input, so that the DC-DC circuit has no power output and the MCU is powered off. Two minutes later, the PWM detection circuit receives the PWM signal, so that the DC-DC circuit outputs power, and the MCU is powered on and reset, exiting the dead state.

[0035] In some embodiments of the present disclosure, referring to Figure 3 , Figure 4 The PWM detection circuit adopts a multi-stage amplifier circuit, and controls the power output of the DC-DC circuit by turning on and off the multi-stage amplifier circuit.

[0036] Specifically, the multi-stage amplifier circuit includes a first-stage amplifier circuit and a second-stage amplifier circuit connected to the output end of the first-stage amplifier circuit.

[0037] The first-stage amplifier circuit includes an NPN transistor V32, a DC power supply VCC, a resistor R33 and a resistor R28;

[0038] The input end of the first-stage amplifier circuit is connected to the base of the transistor V32 through a capacitor C31 and a resistor R34 connected in series, the collector of the transistor V32 is connected to the DC power supply VCC through resistors R36 and R35 connected in series in sequence, and the emitter of the transistor V32 is grounded; one end of the resistor R33 is connected to the DC power supply VCC, and the other end is connected between the capacitor C31 and the resistor R34; one end of the resistor R28 is connected between the resistor R34 and the base of the transistor V32, and the other end is grounded;

[0039] The secondary amplifier circuit includes a PNP transistor V31, the base of the transistor V31 is connected between resistors R36 and R35, the emitter of the transistor V31 is connected to a DC power supply VCC, and the collector of the transistor V31 is connected in series with resistor R37 and then divided into three paths, one of which is grounded through a capacitor C32, one is grounded through a resistor R38, and one is connected to the control end of the DC-DC circuit.

[0040] When there is no PWM signal input, due to the DC isolation effect of C31, the base bias of transistor V32 cannot make it turn on, so transistor V31 is also not turned on, the control terminal EN is grounded through resistor R38, the DC power supply VCC cannot be transmitted to the control terminal EN of the DC-DC circuit, the DC-DC circuit has no 5V voltage output, and the MCU is in a power-off state.

[0041] When there is a PWM signal input, due to the charging and discharging effect of C31, when the PWM signal is at a high level, the transistor V32 is turned on, the voltage drop across the resistor R35 increases, the transistor V31 is turned on, and the DC power supply VCC charges the capacitor C32 through the resistor R37. The control terminal EN of the DC-DC circuit has a voltage, thereby controlling the DC-DC circuit to output a voltage to the MCU, so that the MCU works normally.

[0042] For example, the DC power supply VCC=15V, the resistor R37=2.2K, and the resistor R38=47K. The resistor R37 is much smaller than R38, so when the PWM duty cycle is 50%, the voltage on C32 can be maintained above 5V. When the control terminal EN of the DC-DC circuit is higher than 1.6V, the DC-DC circuit can work normally and output 5V voltage to the MCU.

[0043] In addition, a voltage regulator D32 is connected in parallel to both ends of the resistor R38 to ensure the stability of the voltage at the control end EN of the DC-DC circuit.

[0044] Another aspect of the present disclosure provides a refrigerator, including the above-mentioned circuit for eliminating inverter crashes. The circuit for eliminating inverter crashes is set in the refrigerator, and the inverter crashes can be eliminated without changing the main control board and the MCU interface. The circuit disclosed in the present disclosure can solve the crashes caused by program runaway and voltage latching without changing the inverter and the main control board interface. The implementation method is simple, the cost is low, and the standby power consumption can be reduced.

[0045] Reference Figure 5 The present disclosure also provides a refrigerator control method, which can eliminate the freeze of the inverter, and specifically includes the following steps: when the main control board detects that the inverter is frozen, it stops sending the PWM signal, and the PWM detection circuit is turned off to control the DC-DC circuit to power on the MCU; after the first preset time, the main control board resends the PWM signal, and the PWM detection circuit is turned on to control the DC-DC circuit to power on the MCU, and exits the freeze state.

[0046] The step of detecting the inverter crash includes: detecting that the compressor is in an operating state, the evaporator temperature does not drop and the operation exceeds a second preset time, and determining that the inverter crashes.

[0047] In addition, when the main control board resends the PWM signal after the first preset time, the timer is cleared to facilitate the start of the next timing.

[0048] For example, when the main control board detects that the compressor is in operation, the temperature of the evaporator does not drop and the operation exceeds 10 minutes, it determines that the inverter may be frozen, stops sending the PWM signal for 2 minutes, and then sends the PWM signal again, eliminates the 10-minute timer, powers on and resets the MCU, and exits the frozen state.

[0049] According to the refrigerator control method disclosed in the present invention, when the main control board detects that the inverter is frozen, it stops sending the PWM signal and then resends the PWM signal, so that the MCU can be powered on and reset to exit the frozen state.

[0050] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A circuit for eliminating inverter freeze, characterized in that: include: A main control board, an MCU, a PWM detection circuit, and a DC-DC circuit for providing power to the MCU; The main control board sends a PWM signal, and the output end of the PWM signal is divided into two paths, one of which is connected to the MCU, and the MCU is used to control the operation of the inverter according to the PWM signal; the other path is connected to the input end of the PWM detection circuit, and the output end of the PWM detection circuit is connected to the control end of the DC-DC circuit, which is used to control the power output of the DC-DC circuit to the MCU; Wherein, the PWM detection circuit is turned on and controls the DC-DC circuit to output power when a PWM signal is input, so as to power on the MCU; the PWM detection circuit is not turned on when no PWM signal is input, so that the DC-DC circuit has no power output, so as to power off the MCU; When the main control board detects that the inverter is dead, it stops sending PWM signals for a period of time and then resends them. The PWM detection circuit controls the DC-DC circuit to first power off the MCU and then power on and reset it to make the inverter exit the dead state. The PWM detection circuit is a multi-stage amplifier circuit; the multi-stage amplifier circuit includes: a first-stage amplifier circuit and a second-stage amplifier circuit connected to the output end of the first-stage amplifier circuit; the first-stage amplifier circuit includes an NPN transistor V32, a DC power supply VCC, a resistor R33 and a resistor R28; The input end of the first-stage amplifier circuit is connected to the base of the transistor V32 through a capacitor C31 and a resistor R34 connected in series, the collector of the transistor V32 is connected to the DC power supply VCC through a resistor R36 and a resistor R35 connected in series, and the emitter of the transistor V32 is grounded; one end of the resistor R33 is connected to the DC power supply VCC, and the other end is connected between the capacitor C31 and the resistor R34; one end of the resistor R28 is connected between the resistor R34 and the base of the transistor V32, and the other end is grounded; The secondary amplifier circuit includes a PNP transistor V31, the base of the transistor V31 is connected between the resistor R36 and the resistor R35, the emitter of the transistor V31 is connected to the DC power supply VCC, and the collector of the transistor V31 is connected in series with a resistor R37 and then divided into three paths, one of which is grounded through a capacitor C32, one is grounded through a resistor R38, and one is connected to the control end of the DC-DC circuit.

2. The circuit for eliminating inverter freeze according to claim 1, characterized in that: The two ends of the resistor R38 are connected in parallel with a voltage regulator tube.

3. A refrigerator, characterized in that: The invention comprises the circuit for eliminating inverter freeze as claimed in claim 1 or 2.

4. A refrigerator control method, characterized in that: The refrigerator according to claim 3 comprises the following steps: When the main control board detects that the inverter has crashed, it stops sending PWM signals, and the PWM detection circuit is turned off to control the DC-DC circuit to power off the MCU; after the first preset time, the main control board resends the PWM signal, and the PWM detection circuit is turned on to control the DC-DC circuit to power on the MCU, exiting the crash state.

5. The refrigerator control method according to claim 4, characterized in that: in, The step of detecting a frequency converter crash includes: detecting that the compressor is in an operating state, the evaporator temperature does not drop, and the operation exceeds a second preset time.

6. The refrigerator control method according to claim 4, characterized in that: in, The timer is cleared when the main control board resends the PWM signal after the first preset time.

Images