| 摘要 |
PROBLEM TO BE SOLVED: To prevent the accuracy of vector control operation from lowering by identifying the actual driving frequency of a compressor through frequency analysis of current at DC section and performing vector operation while correcting the secondary resistance thereby eliminating the effect of temperature variation of secondary resistor on the calculation of slip frequency and torque current command. SOLUTION: A frequency analysts section 40 receives a current waveform from the DC section of a current detector 38 and analyzes the frequency. An actual r.p.m. determining section 41 receives an output from the frequency analysis section 40 and determines the actual driving r.p.m. of a compressor 1 with reference to the output from an adder thus producing actual r.p.m. and slip frequency of the compressor. A secondary resistance correcting section 49 compares one output from the actual r.p.m. determining section 41, i.e., a slip frequency, with the output from an operating unit, i.e., a calculated slip frequency, to calculate a corrected secondary resistance which is then delivered to a torque current operating section 48. This constitution prevents the accuracy of vector operation from lowering accompanied by lowering of accuracy of slip frequency operation caused by temperature variation of secondary resistance. |
