Load driving system and electric vehicle using the system

A load driving system driving an AC motor with the use of a DC power supply, the system comprising:

• a pair of DC power supply units connected together in series at a connection point to form the DC power supply, the connection point being at an intermediate potential between a positive potential and a negative potential;
• a positive electrode side line with a first end thereof connected to a positive electrode side of the DC power supply through a positive electrode side switching circuit;
• a negative electrode side line with a first end thereof connected to a negative electrode side of the DC power supply through a negative electrode side switching circuit;
• an intermediate potential line with a first end thereof connected to the intermediate potential point;
• a DC to DC converter unit having at least two switching devices connected in series between the positive electrode side line and the negative electrode side line;
• a DC link circuit having a DC link capacitor connected in parallel with the DC to DC converter unit and between the positive electrode side line and the negative electrode side line;
• and
• a DC to AC converter unit connected to a second end of the positive electrode side line and a second end of the negative electrode side line and in parallel with the DC link capacitor in the DC link circuit to convert DC power in the DC link circuit to AC power to supply the AC power to the AC motor,
• wherein the second end of the intermediate potential line is connected to the connection point, and
• a reactor is provided in at least either the intermediate potential line or each of the positive electrode side line and the negative electrode side line.