Patent ID: 7669430

Claim:
A heat pump apparatus comprising: a compressor for compressing a refrigerant, a radiator for cooling the refrigerant compressed by said compressor, an expander for expanding the refrigerant which passed through said radiator, an evaporator for vaporizing the refrigerant which is expanded by said expander, a refrigerant pipe for circulating the refrigerant through said compressor, said radiator, said expander and said evaporator, a permanent magnet type synchronization power generator connected to said expander, a current sensor for detecting current which flows through said permanent magnet type synchronization power generator, and a first converter which converts AC power which is output from said permanent magnet type synchronization power generator into DC power, which estimates a magnetic pole position of said permanent magnet type synchronization power generator by a current value detected by said current sensor, and which controls the number of revolutions of said permanent magnet type synchronization power generator to a predetermined value by using the current value and the magnetic pole position, wherein the power generator is actuated in a power mode by said first converter when a predetermined time is elapsed after said compressor is actuated.