Dual power refrigerator

A rotary-compressor control system for electric refrigerators having motor-driven rotary compressors to cool the inside of the electric refrigerator, characterized in that said rotary-compressor control system comprising

• a battery for supplying a battery voltage not higher than 24 volts,
• a switching power section having a rectifying section and an inverter section for rectifying commercial a-c power in said rectifying section, and changing a voltage of said commercial a-c power to a magnitude of said battery voltage in said inverter section;
• an inverter power section receiving d-c power supplied from said battery or said switching power section via an automatic changeover means and converting said d-c power into a three-phase a-c voltage to feed to said motor that drives said rotary compressor;
• control means for changing said automatic changeover means preferentially to the side of said switching power section when commercial a-c power is used, producing an optimal control signal fed to said inverter power section on the basis of a pressure detection signal from said rotary compressor, and generating an alarm signal when said pressure detection signal indicates an abnormal state of said rotary compressor;
• and
• a delta-Y changing means for changing over a configuration of said three-phase induction motor from a delta configuration to a Y configuration and vice versa is provided, said changing means causing said three-phase induction motor to be driven in said delta configuration when battery voltage is 12 V, and in said Y configuration when battery voltage is 24 V.

A dual power refrigerator comprising:

• a refrigerator housing;
• a rotary compressor connected to said refrigerator housing and for cooling said refrigerator housing;
• a three-phase induction motor connected to said rotary compressor and rotating said rotary compressor to perform said cooling;
• power inverter means for receiving d-c power and converting said d-c power into three-phase power supplied to said induction motor at a motor voltage, said d-c power being at a voltage substantially similar to said motor voltage;
• changeover means for changing between a first and second source of said d-c power to said power inverter means;
• battery terminal means connected to said first source of said change over means and for receiving battery d-c power at one of first and second battery voltages, said second battery voltage being substantially twice said first battery voltage said motor voltage being substantially similar to said one of said battery voltages;
• commercial a-c power means connected to said second source of said changeover means and for receiving commercial a-c power at a voltage larger than said first and second battery voltages, said commercial a-c power means rectifying and lowering said commercial a-c power to a magnitude of one of said first and second battery voltages;
• control means connected to said commercial a-c power means and said changeover means to change said changeover means to said second source when said commercial a-c power means is receiving said commercial power, said control means also connected to said power inverter means and receiving an external control command signal from an operator for controlling said power inverter section;
• and
• delta-Y changing means connected between said power inverter means and said three-phase induction motor, and for changing a configuration of said three-phase induction motor between a Y configuration of said three-phase induction motor between a Y configuration and a delta configuration, said delta-Y changing means connecting said three-phase induction motor in said delta configuration when said first battery voltage is received, said delta-Y changing means connecting said three-phase induction motor in said Y configuration when said second battery voltage is received.

A method for operating a multi power refrigerator comprising:

• providing a refrigerator housing;
• providing a rotary compressor connected to said refrigerator housing and for cooling said refrigerator housing;
• providing a three-phase induction motor connected to said rotary compressor and rotating said rotary compressor to perform said cooling;
• providing power inverter means for receiving d-c power and converting said d-c power into three-phase power supplied to said induction motor at a motor voltage, said d-c power being at a voltage substantially similar to said motor voltage;
• providing changeover means for changing between a first and second source of said d-c power to said power inverter means;
• providing battery terminal means connected to said first source of said change over means and for receiving battery d-c power at a one of a first and second battery voltage, said second battery voltage being substantially twice said first battery voltage, said motor voltage substantially following said battery voltage;
• providing commercial a-c power means connected to said second source of said changeover means and for receiving commercial a-c power at a voltage larger than said first and second battery voltages, said commercial a-c power means rectifying and lowering said commercial a-c power to a magnitude of one of said first and second battery voltages;
• providing control means connected to said commercial a-c power means and said changeover means to change said changeover means to said second source when said commercial a-c power means is receiving said commercial power, said control means also connected to said power inverter means and receiving an external control command signal from an operator for controlling said power inverter section;
• providing delta-Y changing means connected between said power inverter means and said three-phase induction motor, and for changing a configuration of said three-phase induction motor between a Y configuration and a delta configuration;
• changing said configuration of said three-phase induction motor to said delta configuration when said first battery voltage is received;
• changing said configuration of said three-phase induction motor to said Y configuration when said second battery voltage is received.