Charging power supplying system using motor driving system

1. A charging power supplying system using a motor driving system, comprising:

an inverter that is connected to a battery, includes at least one switching device, and is configured to change an on/off state of the switching device and to convert power stored in the battery to output the converted power to an output terminal of the inverter;

a motor including a plurality of coils that each receive power provided from the output terminal of the inverter;

a charging power output terminal that is connected to a neutral point to which the plurality of coils of the motor is commonly connected and outputs current output from the neutral point to an external charging target; and

a controller configured to control a switching device in the inverter based on current of the output terminal of the inverter such that an amplitude of current output to the charging power output terminal from the neutral point follows a preset current command,

wherein the controller determines a duty of the switching device in the inverter based on a difference between a current detection value obtained by detecting current output from the neutral point and a preset neutral point current command, and direct current (DC) link voltage corresponding to voltage of a side of the battery of the inverter, and

wherein the controller further includes a nonlinearity compensator configured to generate a nonlinearity compensation duty for compensating for nonlinearity of the inverter based on a detection value DC link voltage of the inverter and detection value of the neutral point current.

2. The charging power supplying system of claim 1 , wherein the controller includes a current control device including a subtracter configured to calculate a difference between a current detection value obtained by detecting current output from the neutral point and a preset neutral point current command, a control device configured to generate a voltage command value for allowing a calculation result of the subtracter to converge on ‘0’, and a divider configured to determine a first switching duty of the switching device in the inverter, which corresponds to a ratio of direct current (DC) link voltage corresponding to voltage of an input terminal of the side of the battery of the inverter and the voltage command value.

3. The charging power supplying system of claim 1 , wherein the controller further includes:

an adder configured to add the first switching duty and the nonlinearity compensation duty to generate a correction duty.

4. The charging power supplying system of claim 3 , wherein the controller further includes a current unbalance reduction control unit configured to correct the correction duty to allow a difference between an average value of detection values of currents flowing in coils with a plurality of phases of the motor and a detection value of each of the currents flowing in the coils with the plurality of phases to converge on ‘0’, and to generate a separate duty determined for each switching device connected to the coils with the plurality of phases.

5. The charging power supplying system of claim 4 , wherein the current unbalance reduction control unit includes:

a plurality of subtracters configured to each calculate a difference between the average value of the detection values of the currents flowing in the coils with the plurality of phases of the motor and the detection value of each of the currents flowing in the coils with the plurality of phases;

a plurality of control devices configured to each generate a duty value for allowing a calculated value of the plurality of subtracters to converge on ‘0’; and

a plurality of adders configured to add the correction duty to each of duty values generated by the plurality of control devices to the correction duty to each generate a separate duty of the switching device in the inverter connected to the coils with the plurality of phases.

6. The charging power supplying system of claim 4 , wherein the current unbalance reduction control unit includes:

a plurality of subtracters configured to each calculate a difference between an average value of the detection values of the currents flowing in the coils with the plurality of phases in the motor and a detection value of each of currents flowing in remaining phases except for one of currents flowing in coils with a plurality of phases;

a plurality of control devices configured to each generate a duty value for allowing a calculated value of the plurality of subtracters to converge on ‘0’;

a first adder configured to change a sign of the duty values generated by the plurality of control devices and to add resulting values; and

a plurality of second adders configured to add each of the duty values generated by the plurality of control devices and a duty value added by the first adder to the correction duty to respectively generate separate duties of the switching device in the inverter connected to the coils with the plurality of phases.

7. The charging power supplying system of claim 4 , wherein the controller further includes a signal output unit configured to generate and output a switching device driving signal corresponding to the separate duty for driving the switching device.

8. The charging power supplying system of claim 7 , wherein the signal output unit generates the switching device driving signal to perform interleaved switching on switching devices connected to each phase of the motor.