A motor driving apparatus including a regeneration control function and a power
storage device for accumulating a regenerative current and for supplying an inverter
section with electric power during acceleration. The inverter section is connected
to a converter section by a DC link to which regeneration start detecting means
and the power storage device are connected. When the regeneration start detecting
means detects that a voltage at the DC link reaches a regeneration control start
voltage, a controller controls switching elements and starts regeneration control.
The regenerative current is accumulated in the capacitor through a diode. When
a motor is in a power running state, the switching elements are turned on to apply
the voltage at the power storage device to the DC link, and the charged power is
utilized for motor acceleration. At that time, the regeneration control start voltage
for the regeneration start detecting means is made higher, thereby preventing regeneration
control from being activated due to application of the capacitor's voltage. Not
only the regenerative current is effectively utilized by the power storage device,
but also the regeneration control function can be utilized.