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CN-122026274-A - Overheat protection circuit, controller, outdoor unit and air conditioner

CN122026274ACN 122026274 ACN122026274 ACN 122026274ACN-122026274-A

Abstract

The invention discloses an overheat protection circuit, which relates to the technical field of air conditioners and comprises a temperature acquisition module, an overheat protection trigger module, a signal hysteresis module and a control module, wherein the overheat protection trigger module is connected with the temperature acquisition module and is used for outputting overheat protection trigger signals according to temperature, the signal hysteresis module is connected with the overheat protection trigger module and is used for adjusting the numerical value of the overheat protection trigger signals output by the overheat protection trigger module to be a first value when the temperature is greater than a first temperature threshold value and adjusting the numerical value of the overheat protection trigger signals output by the overheat protection trigger module to be a second value when the temperature is less than a second temperature threshold value, and the control module is connected with the overheat protection trigger module and is used for performing overheat protection treatment according to the overheat protection trigger signals output by the overheat protection trigger module. The embodiment of the invention can prolong the service life of the device and enhance the control precision and stability of the system.

Inventors

  • LI NING
  • YAN XIAOJUN

Assignees

  • 佛山市顺德区美的电子科技有限公司
  • 广东美的制冷设备有限公司

Dates

Publication Date
20260512
Application Date
20241112

Claims (12)

  1. 1. An overheat protection circuit, comprising: the temperature acquisition module is used for acquiring the temperature of the power device in the main control board of the air conditioning system; The overheat protection triggering module is connected with the temperature acquisition module and is used for outputting overheat protection triggering signals according to the temperature; The signal hysteresis module is connected with the overheat protection triggering module and is used for enabling the value of the overheat protection triggering signal output by the overheat protection triggering module to be adjusted to a first value when the temperature is larger than a first temperature threshold value and enabling the value of the overheat protection triggering signal output by the overheat protection triggering module to be adjusted to a second value when the temperature is smaller than a second temperature threshold value, wherein the first temperature threshold value is larger than the second temperature threshold value, and the first value is smaller than the second value; And the control module is connected with the overheat protection triggering module and is used for performing overheat protection treatment according to the overheat protection triggering signal output by the overheat protection triggering module.
  2. 2. The overheat protection circuit of claim 1, wherein the overheat protection triggering module comprises a positive input, a negative input and an output, the negative input is connected to the temperature acquisition module, the output is connected to the control module, and the output is further connected to the positive input through the signal hysteresis module.
  3. 3. The overheat protection circuit of claim 2, wherein the signal hysteresis module comprises a first signal hysteresis resistor and a second signal hysteresis resistor connected to each other, the first signal hysteresis resistor is connected to the output terminal, and a junction of the first signal hysteresis resistor and the second signal hysteresis resistor is connected to the positive input terminal.
  4. 4. The overheat protection circuit of claim 3, further comprising a second voltage divider network, the second voltage divider network being connected to the second signal hysteretic resistor.
  5. 5. The overheat protection circuit of claim 4 wherein the second voltage divider network comprises a second input terminal, a second output terminal and a second ground terminal, a third voltage divider resistor is connected between the second input terminal and the second output terminal, a fourth voltage divider resistor is connected between the second output terminal and the second ground terminal, the second input terminal is connected to a power supply, the second output terminal is connected to the second signal hysteresis resistor, and the second ground terminal is connected to a reference ground.
  6. 6. The overheat protection circuit of claim 2, further comprising a first voltage divider network connected between the temperature acquisition module and the negative input.
  7. 7. The overheat protection circuit of claim 6, wherein the temperature acquisition module comprises a power connection, a signal output and a temperature acquisition device, the temperature acquisition device being connected between the power connection and the signal output, the power connection being connected to a first power supply, the first voltage divider network being connected between the signal output and the negative input.
  8. 8. The overheat protection circuit of claim 7, wherein the first voltage divider network comprises a voltage divider input and a first ground, a voltage divider resistor is connected between the voltage divider input and the first ground, the voltage divider input is connected to the signal output, the voltage divider input is further connected to the negative input through a current limiting resistor, and the first ground is connected to a reference ground.
  9. 9. The overheat protection circuit of claim 1, further comprising a level bias module connected to the overheat protection trigger module for level adjustment of the overheat protection trigger signal output by the overheat protection trigger module.
  10. 10. A controller comprising the overheat protection circuit of any one of claims 1 to 9.
  11. 11. An outdoor unit comprising the overheat protection circuit according to any one of claims 1 to 9, or comprising the controller according to claim 10.
  12. 12. An air conditioner comprising the overheat protection circuit according to any one of claims 1 to 9, or comprising the controller according to claim 10, or comprising the outdoor unit according to claim 11.

Description

Overheat protection circuit, controller, outdoor unit and air conditioner Technical Field The present invention relates to the field of air conditioners, and more particularly, to an overheat protection circuit, a controller, an outdoor unit, and an air conditioner. Background The common overheat protection mode of the existing power device is that only one thermistor is integrated in the device, two pins of the thermistor are externally connected, one end of the thermistor is connected with a power supply, the other end of the thermistor is connected with a fixed resistor, resistor voltage division is input into an AD port of an MCU, when the temperature of the thermistor changes, the resistor voltage division value changes along with the temperature change, the MCU stops PWM signal output when the temperature reaches a first preset temperature, and the MCU resumes PWM signal output when the temperature drops to a second preset temperature. However, for some MCU devices without AD port resources, a triode or a comparator may be used to process the resistor voltage division signal, but the protection trigger value of the triode or the comparator circuit is only one, when the temperature reaches the first preset temperature, the resistor voltage division value reaches the protection trigger preset voltage, the output signal of the circuit is turned to a low level, when the temperature is slightly lower than the first preset temperature, the resistor voltage division value V2 is slightly lower than the protection trigger preset voltage, the output signal of the circuit is turned to a high level again, that is, the protection point and the recovery point are the same point, when the temperature fluctuates around the point, the state of the circuit can repeatedly jump between the working and the protection, the ageing process of the device is easy to accelerate, and the motor rotation speed fluctuation may also be caused, and the control precision and stability of the system are affected. Disclosure of Invention The invention aims to at least solve one of the technical problems in the prior art and provide an overheat protection circuit, a controller, an outdoor unit and an air conditioner, which can prolong the service life of devices and enhance the control precision and stability of a system. In a first aspect, an embodiment of the present invention provides an overheat protection circuit, which includes a temperature acquisition module, an overheat protection trigger module, a signal hysteresis module, and a control module, where the temperature acquisition module is configured to acquire a temperature of a power device in a main control board of an air conditioning system, the overheat protection trigger module is connected to the temperature acquisition module and configured to output an overheat protection trigger signal according to the temperature, the signal hysteresis module is connected to the overheat protection trigger module and configured to adjust a value of the overheat protection trigger signal output by the overheat protection trigger module to a first value when the temperature is greater than a first temperature threshold, and adjust a value of the overheat protection trigger signal output by the overheat protection trigger module to a second value when the temperature is less than a second temperature threshold, where the first temperature threshold is greater than the second temperature threshold and the first value is less than the second value, and the control module is connected to the overheat protection trigger module and configured to perform overheat protection processing according to the overheat protection trigger signal output by the overheat protection trigger module. In some embodiments, the overheat protection triggering module includes a positive input terminal, a negative input terminal, and an output terminal, wherein the negative input terminal is connected with the temperature acquisition module, the output terminal is connected with the control module, and the output terminal is further connected with the positive input terminal through the signal hysteresis module. In some embodiments, the signal hysteresis module includes a first signal hysteresis resistor and a second signal hysteresis resistor connected to each other, the first signal hysteresis resistor is connected to the output terminal, and a junction of the first signal hysteresis resistor and the second signal hysteresis resistor is connected to the positive input terminal. In some embodiments, the overheat protection circuit further comprises a second voltage divider network, the second voltage divider network being connected to the second signal hysteretic resistor. In some embodiments, the second voltage dividing network includes a second input end, a second output end and a second ground end, a third voltage dividing resistor is connected between the second input end and the second output end, a fourth vo