A power converter to convert power from a power supply into power supplied to a motor including n-phase windings, where n is an integer of 3 or more, in which first ends thereof are Y-connected and includes an inverter connected to second ends of the n-phase windings, a phase separation relay circuit to switch connection and disconnection between the power supply and the n-phase windings for each phase, a neutral point leg connected to a neutral point node of the motor, in which the first ends of the n-phase windings are Y-connected, and a neutral point separation relay circuit to switch connection and disconnection between the power supply and the neutral point node.

Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.

A device for driving a plurality of motors and an electric apparatus having the same is disclosed. The device includes an inverter connected to a DC terminal, a multi-phase motor connected to the inverter, a single-phase motor serially connected to the multi-phase motor, and a first capacitor and a second capacitor connected in series between a first end and a second end of the DC terminal, wherein the single-phase motor is connected to the multi-phase motor, and a node between the first capacitor and the second capacitor. Accordingly, a plurality of motors serially connected with each other can be driven by using a single inverter.

A device for driving a plurality of motors, including an inverter connected to a DC terminal; a multi-phase motor connected to the inverter; and a single-phase motor serially connected to the multi-phase motor, wherein a number of frequency of current input to the multi-phase motor when driving the single-phase motor and the multi-phase motor at the same speed is smaller than the number of frequency of current input to the multi-phase motor when driving the single-phase motor and the multi-phase motor at different speeds. Accordingly, a plurality of motors can be simultaneously driven at different speeds, by using a single inverter.

A charging system and a charging method using a motor driving system are disclosed which may enable charging between vehicles each having a battery for providing power to a vehicle driving motor, such as electric vehicles or plug-in hybrid vehicles.

A power tool is provided including: an electric brushless direct current (BLDC) motor having a rotor and a stator. The stator includes at least six teeth including a first set of teeth on which a first set of stator windings are wound and a second set of teeth on which a second set of stator windings are wound. The first and second sets of stator windings are alternatingly arranged relative to the stator. The first set of stator windings is connected in a wye configuration and the second set of stator windings is connected in delta configuration.

Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.

A motor driving device controls a three-phase motor and a single-phase motor to operate in parallel. The motor driving device includes a dc terminal in which an upper and a lower DC-link capacitor are located. The motor driving device also includes a neutral terminal disposed between the upper and lower DC-link capacitors. The motor driving device includes an inverter that includes three pairs of upper switching elements and lower switching elements. Two pairs of upper switching elements and lower switching elements among three pairs are connected to a-phase terminal and b-phase terminal of the three-phase motor, respectively. The other pair of upper switching elements and lower switching elements among three pairs is connected to a first terminal of the single-phase motor. The neutral terminal is connected to c-phase terminal of the three-phase motor and a second terminal of the single-phase motor.

A drive apparatus is provided for driving a rotating electric machine having first and second multi-phase coils. The drive apparatus includes first and second inverters, first and second shift switches, and first and second energization controllers. The first energization controller is configured to turn on and off, for each of phase windings of the first and second multi-phase coils, one corresponding pair of upper-arm and lower-arm switches of the first and second inverters while keeping the first and second shift switches in an OFF state. The second energization controller is configured to turn on and off, for each corresponding pair of the phase windings of the first and second multi-phase coils, one corresponding upper-arm switch of the first inverter and one corresponding lower-arm switch of the second inverter respectively for first energization periods and second energization periods that are alternately set while keeping the shift switches in an ON state.

A power tool is provided including: an electric brushless direct current (BLDC) motor having rotor and a stator defining phases; a power unit including a first switch circuit connected electrically between a first power supply and the motor, and a second switch circuit connected electrically between a second power supply and the motor; and a controller configured to control a switching operation of the first switch circuit and the second switch circuit to regulate a supply of power from at least one of the first power supply and/or the second power supply to the motor.