Plug-in circuit and cooling system thereof

Abstract

The present invention relates to a plug-in circuit and a cooling system thereof. The cooling system includes the plug-in circuit, an external terminal and an alternating current (AC) compressor, wherein the plug-in circuit includes an AC to AC inverter and an inverter control circuit. The AC to AC inverter is coupled to and between the external terminal and the AC compressor for converting an external AC voltage received by the external terminal to an internal AC voltage to supply to the AC compressor. The inverter control circuit is coupled to the AC to AC inverter for outputting a control signal to the AC to AC inverter to control the frequency of the internal AC voltage according to an external parameter.

1 . A plug-in circuit, disposed on a cooling system, wherein the cooling system comprises an external terminal and an alternating current (AC) compressor, the plug-in circuit comprising:
 an AC to AC inverter, coupled to and between the external terminal and the AC compressor, for converting an external AC voltage received by the external terminal to an internal AC voltage to supply the AC to the AC compressor; and   an inverter control circuit, coupled to the AC to AC inverter, for outputting a control signal to AC to AC inverter to control frequency of the internal AC voltage according to an external parameter.   
   
   
       2 . The plug-in circuit according to  claim 1 , wherein the external parameter comprises environment's temperature. 
   
   
       3 . The plug-in circuit according to  claim 2 , wherein the inverter control circuit controls the AC to AC inverter in a fixed frequency of the internal AC voltage when the environment's temperature varies within a preset range. 
   
   
       4 . The plug-in circuit according to  claim 2 , wherein the inverter control circuit controls to increase the frequency of the internal AC voltage a preset value at each preset time when the environment's temperature is higher than a first boundary limit of temperature of a preset range, the inverter control circuit controls to decrease the frequency of the internal AC voltage the preset value at each preset time when the environment's temperature is lower than a second boundary limit of temperature of the preset range. 
   
   
       5 . The plug-in circuit according to  claim 1 , wherein the inverter control circuit is coupled to the AC compressor and the external parameter is refrigerant pressure. 
   
   
       6 . The plug-in circuit according to  claim 5 , wherein the inverter control circuit controls to decrease the frequency of the internal AC voltage a preset value at each preset time when the refrigerant pressure is lower than a first boundary limit of pressure of a preset range, the inverter control circuit controls to increase the frequency of the internal AC voltage the preset value at each preset time when the refrigerant pressure is higher than a second limit of pressure of the preset range. 
   
   
       7 . The plug-in circuit according to  claim 5 , wherein the inverter control circuit controls the AC to AC inverter in a fixed frequency of the internal AC voltage when the refrigerant pressure varies within a preset range. 
   
   
       8 . The plug-in circuit according to  claim 1 , wherein the AC to AC inverter sets the frequency of the internal AC voltage to a preset frequency when the frequency of the internal AC voltage is higher than or equal to a preset frequency. 
   
   
       9 . The plug-in circuit according to  claim 1 , wherein the cooling system further comprises a indoor unit coupled to the inverter control circuit, wherein the indoor unit is used for detecting an indoor temperature to output a start-on signal to the inverter control circuit, wherein the start-on signal is disabled when the indoor temperature is lower than a preset value, and then the AC compressor is disabled. 
   
   
       10 . The plug-in circuit according to  claim 1 , wherein the inverter control circuit is coupled to the AC compressor for detecting a temperature or a refrigerant pressure of the AC compressor, when the refrigerant pressure of the AC compressor is higher than a protected pressure, the inverter control circuit controls the AC to AC inverter to stop the AC compressor, when the temperature of the AC compressor is higher than a protected temperature, the inverter control circuit controls the AC to AC inverter to stop the AC compressor. 
   
   
       11 . A cooling system, comprising:
 an external terminal, receiving an external alternating current (AC) voltage;   an AC compressor;   an AC to AC inverter, coupled to and between the external terminal and the AC compressor for converting an external AC voltage to an internal AC voltage to supply to the AC compressor; and   an inverter control circuit, coupled to the AC to AC inverter, for outputting a control signal to the AC to AC inverter to control frequency of the internal AC voltage according to an external parameter.   
   
   
       12 . The cooling system according to  claim 11 , wherein the external parameter is environment's temperature. 
   
   
       13 . The cooling system according to  claim 12 , wherein the inverter control circuit controls the AC to AC inverter in a fixed frequency of the internal AC voltage when the environment's temperature varies within a preset range. 
   
   
       14 . The cooling system according to  claim 12 , wherein the inverter control circuit controls to increase the frequency of the internal AC voltage a preset value at each preset time when the environment's temperature is higher than the first boundary limit of temperature of a preset range, the inverter control circuit controls to decrease the frequency of the internal AC voltage the preset value at each preset time when the environment's temperature is lower than the second boundary limit of temperature of the preset range. 
   
   
       15 . The cooling system according to  claim 11 , wherein the inverter control circuit is coupled to the AC compressor and the external parameter is refrigerant pressure. 
   
   
       16 . The cooling system according to  claim 15 , wherein the inverter control circuit controls to decrease the frequency of the internal AC voltage a preset value at each preset time when the refrigerant pressure is lower than a first boundary limit of pressure of a preset range, the inverter control circuit controls to increase the frequency of the internal AC voltage the preset value at each preset time when the refrigerant pressure is higher than a second boundary limit of pressure of the preset range. 
   
   
       17 . The cooling system according to  claim 15 , wherein the inverter control circuit controls the AC to AC inverter in a fixed frequency of the internal AC voltage when the refrigerant pressure varies within a preset range. 
   
   
       18 . The cooling system according to  claim 11 , wherein the AC to AC inverter sets the frequency of the internal AC voltage to a preset frequency when the frequency of the internal AC voltage is higher than or equal to a preset frequency. 
   
   
       19 . The cooling system according to  claim 11 , wherein the cooling system further comprises a indoor unit coupled to the inverter control circuit, wherein the indoor unit is used for detecting an indoor temperature to output a start-on signal to the inverter control circuit, wherein the start-on signal is disabled when the indoor temperature is lower than a preset value, and then the AC compressor is disabled. 
   
   
       20 . The cooling system according to  claim 11 , wherein the inverter control circuit is coupled to the AC compressor for detecting a temperature and a refrigerant pressure of the AC compressor, when the refrigerant pressure of the AC compressor is larger than a secured pressure or the temperature of the AC compressor is larger than a secured temperature, the inverter control circuit controls the AC to AC inverter to stop the AC compressor.