Open winding motor driving device
A primary-side inverter is connected to three output terminals of six output terminals included in a motor with an open winding structure including windings of three independent phases and a secondary-side inverter is connected to the remaining three output terminals. Direct current power is supplied to the inverters, and a control device performs PWM control on the inverters by using a switching pattern in which the numbers of phases where each is turned on are equal, and in the switching pattern, ON of only an upper is continued in one phase from among the three phase outputs, OFF of only a lower is continued in another phase, and the upper and lower are alternately turned on and off such that mutual phases are opposite in the remaining one phase in one cycle of an electric angle of the motor over a plural carrier cycles in PWM control.
1. An open winding motor driving device comprising:
a primary-side inverter that is connected to three output terminals from among six output terminals included in a motor with an open winding structure including the six output terminals and including windings of three phases that are independent of each other;
a secondary-side inverter that is connected to the remaining three output terminals of the output terminals of the motor;
a control unit that controls a current to be distributed to the motor and a rotation speed by controlling the primary-side and secondary-side inverters,
wherein direct current power is supplied to the primary-side and secondary-side inverters,
both the primary-side and the secondary-side inverters comprise respectively three upper switching elements and three lower switching elements,
the control unit performs PWM control on the primary-side and secondary-side inverters by using a switching pattern in which the numbers of phases where each of the switching elements comprising the primary-side and the secondary-side inverters is turned on are equal, and
the opening winding motor driving device has a switching pattern in which ON of only an upper switching element of the three upper switching elements is continued in one phase out of three phase outputs, ON of only a lower switching element of the three lower switching elements is continued in another phase, and the upper and lower switching elements are alternately turned on and off such that mutual phases are opposite in the remaining one phase, in one cycle of an electric angle of the motor over a plurality of carrier cycles in the PWM control.
2. The open winding motor driving device according to claim 1 , wherein the control unit outputs a PWM signal such that timings for performing switching are shifted between the primary-side inverter and the secondary-side inverter.
3. The open winding motor driving device according to claim 2 ,
wherein direct current power is supplied from a converter connected to an alternating current power source to the primary-side and secondary-side inverters, and
the control unit controls an output voltage of the converter such that a modulation factor of the PWM signal is equal to or greater than “1”.
4. The open winding motor driving device according to claim 1 ,
wherein direct current power is supplied from a converter connected to an alternating current power source to the primary-side and secondary-side inverters, and
the control unit controls an output voltage of the converter such that a modulation factor of the PWM signal is equal to or greater than “1”.