Control device of linear compressor drive system

Abstract

A control apparatus for a linear compressor driving system is disclosed for stabilizing the behavior of a piston and thereby protecting the increase in noise vibration caused by collision and the reduction in reliability. This control apparatus stabilizes the behavior of the piston by including: an unstableness detecting means, which directly or indirectly detects that the behavior of the piston is unstable and then outputs an unstableness detection signal; and an unstableness avoiding means which is operated in accordance with the unstableness detection signal.

1 . A control apparatus for a linear compressor driving system, which is used for a linear compressor driving system including: a linear compressor having a linear motor and a piston; and a power supply unit for supplying an electric power to said linear motor, comprising: 
 an unstableness detecting means for detecting that a behavior of said piston is unstable and outputting an unstableness detection signal; and    an unstableness avoiding means that is operated so as to act on said linear compressor driving system in accordance with said unstableness detection signal and thereby avoid the unstable state.    
     
     
         2 . A control apparatus for a linear compressor driving system, which is used for a linear compressor driving system including: a linear compressor having a linear motor and a piston; and a power supply unit for supplying an electric power to said linear motor, comprising: 
 an operating condition detecting means for detecting at least one of a displacement of said piston, an ambient temperature, a temperature at any part of said linear compressor driving system, and an operating pressure, and then outputting a detection signal;    an unstableness detecting means, which if the detection signal of said operating condition detecting means satisfies a predetermined condition, estimates that a behavior of said piston is unstable, and then outputs an unstableness detection signal; and    an unstableness avoiding means that is operated so as to act on said linear compressor driving system in accordance with said unstableness detection signal and thereby avoid the unstable state.    
     
     
         3 . The control apparatus according to  claim 1  or  2 , wherein said unstableness detecting means has a displacement detecting means for detecting a displacement of said piston.  
     
     
         4 . The control apparatus according to  claim 1  or  2 , wherein said unstableness detecting means has a sound and vibration detecting means for detecting sound or vibration of said compressor.  
     
     
         5 . The control apparatus according to  claim 1  or  2 , wherein said unstableness detecting means has a voltage current detecting means for detecting a voltage or a current outputted by said power supply unit.  
     
     
         6 . The control apparatus according to  claim 1  or  2 , wherein said unstableness detecting means has a pressure detecting means for detecting a pressure of a predetermined portion of said linear compressor driving system.  
     
     
         7 . The control apparatus according to  claim 1  or  2 , wherein said unstableness detecting means has an ambient temperature detecting means for detecting an ambient temperature of said linear compressor driving system.  
     
     
         8 . The control apparatus according to  claim 1  or  2 , wherein said unstableness detecting means has a temperature detecting means for detecting a temperature of any part of said linear compressor driving system.  
     
     
         9 . The control apparatus according to  claim 1  or  2 , wherein said unstableness avoiding means is designed so as to change a voltage waveform or a current waveform outputted by said power supply unit in accordance with said unstableness detection signal.  
     
     
         10 . The control apparatus according to  claim 9 , wherein said unstableness avoiding means is designed so as to output, from said power supply unit, voltage waveforms or current waveforms stored in a waveform memory, which stores voltage waveforms or current waveforms having a plurality of patterns, in accordance with said unstableness detection signal.  
     
     
         11 . The control apparatus according to  claim 1  or  2 , wherein said unstableness avoiding means is designed so as to change an impedance of said linear motor in accordance with said unstableness detection signal.  
     
     
         12 . The control apparatus according to  claim 1  or  2 , wherein said unstableness avoiding means has an air blowing amount changing means for changing an air blowing amount to a heat exchanger connected to a linear compressor in accordance with said unstableness detection signal.  
     
     
         13 . The control apparatus according to  claim 12 , wherein said air blowing amount changing means is designed so as to change a rotational speed and/or change an air blowing path of an air blower for blowing an air to said heat exchanger.  
     
     
         14 . The control apparatus according to  claim 1  or  2 , wherein said unstableness avoiding means is designed so as to change a frequency outputted by said power supply unit in accordance with said unstableness detection signal.  
     
     
         15 . The control apparatus according to  claim 1  or  2 , wherein said unstableness avoiding means is designed so as to change a voltage value or a current value outputted by said power supply unit in accordance with said unstableness detection signal.  
     
     
         16 . The control apparatus for a linear compressor driving system according to  claim 1  or  2 , wherein said unstableness detecting means includes: 
 a detecting means for detecting at least one of a current of said power supply unit, a voltage of said power supply unit, and said piston displacement;  
 a target value setting means for setting a target value of said current or said voltage or said piston displacement in accordance with an operating condition of said linear compressor;  
 a timer means for outputting a start signal at a predetermined interval; and  
 a changing means for comparing an output of said detecting means with said target value in accordance with said start signal, and on the basis of a difference between them, changing said voltage or said current at a predetermined change amount, and  
 wherein said unstableness avoiding means is designed so as to change at least one of the change amount of said detecting means and the output interval of the start signal of said timer means, in accordance with said unstableness detection signal.