PURPOSE: To suppress DC voltage rise and to perform stable deceleration control by constituting a regenerative mode judging logic for load where signals from the input current detecting circuit for a power rectifier and the output current detecting circuit for a power inverter are employed.
CONSTITUTION: A logic for judging regenerative mode based on the signals from current detectors 9, 11 is provided. A load regenerative mode 13 receives inputs A and B and produces an H output only when the input A is L and the output B is H. Such state represents regenerative mode operation of a voltage type inverter. Since the load regenerative mode judging circuit 13 judges existence of current based on the table, H state of signal A does not change even if input current to a power rectifier 1 increases due to AC input voltage rise whereby no erroneous function occurs.
MURAKAMI MASASHI
MIYABE TAKAAKI
