| 摘要 |
PURPOSE: To obtain an excitation electric current value which matches with a load by determining an enthalpy of work to be done by a compressor and converting the determined enthalpy into torque and obtaining an excitation current value equivalent to the converted torque value in a control system which increases and decreases the rotary speed of the compressor by using an inverter device. CONSTITUTION: Each output signal of a shell discharge pressure detector 44, a shell discharge temperature detector 56, a shell suction pressure detector 46 and a shell suction temperature detector 47 is inputted into a first enthalpy operator 48 where workload AW of a compressor 1 is operated. Then, a first load torque estimating instrument 48 estimates a required load torque from the workload AW of the compressor and estimates an optimum energizing electric current from the load torque with an excitation electric current setting instrument 50, thereby outputting an excitation electric current setting value to a first vector control signal command arithmetic operation circuit 51. This arithmetic operation circuit 51 inputs a U phase and a V phase electric current measured value from the electric current detectors 42 and 43, and controls an electric current converter 13 by computing a torque electric current from these measured values and exitation electric current setting values. |
