| 摘要 |
PURPOSE: To correctly detect surge occurrence by setting a standard signal from determined time interval average current of a motor current, counting the difference generated in two directions, solving a display count and comparing it with the standard count. CONSTITUTION: Drive current of motor MT for driving a compressor CMP is input into a microcomputer MCP through a coil 50 A/D converter CNV to control opening degree of the inlet valve IV through a compressor control unit CCU. The computer MCP sets a standard signal from determined time interval average current of current signals, counts one by one the difference of the average current with the motor current that is input through an A/D converter in two directions in a determined time interval. While the display count reaches the predetermined standard count, surge condition signals are output to the control unit CCU, so a bypass valve VB is opened and the surge is broken off. By this manner, the surge occurrence is correctly and immediately detected, trouble caused by the surge can be prevented. |
