A power supply system comprising: a plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) connected in parallel and configured to supply electric power to an AC load, each of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) including an output impedance (Z1, Z2) connectable to the AC load, a PWM converter (16A, 16B) configured to convert DC power into AC power, and a controller (20A, 20B, 50A, 50B) configured to output a voltage command value (Eref1, Eref2) to the PWM converter (16A, 16B), the controller (20A, 20B, 50A, 50B) including a vector adder configured to perform vector addition of a part of a voltage drop occurring due to a current flowing through the output impedance (Z1, Z2) and a load voltage command value (ErefL) of the AC load, and a converter configured to output the voltage command value to the PWM converter (16A, 16B) based on a vector sum obtained through the vector addition such that an actual voltage output from each of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) is equal to the voltage command value (Eref1, Eref2), wherein the load voltage command values (ErefL) of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) are equal, the controller (20A, 20B, 50A, 50B) includes a vector multiplier (24A, 24B), and the vector multiplier (24A, 24B) is configured to calculate a part of the voltage drop by multiplying a product of a value of the output impedance (Z 1, Z2) and the current flowing through the output impedance (Z1, Z2) by a coefficient smaller than approximately one. a plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) connected in parallel and configured to supply electric power to an AC load, each of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) including an output impedance (Z1, Z2) connectable to the AC load, a PWM converter (16A, 16B) configured to convert DC power into AC power, and a controller (20A, 20B, 50A, 50B) configured to output a voltage command value (Eref1, Eref2) to the PWM converter (16A, 16B), an output impedance (Z1, Z2) connectable to the AC load, a PWM converter (16A, 16B) configured to convert DC power into AC power, and a controller (20A, 20B, 50A, 50B) configured to output a voltage command value (Eref1, Eref2) to the PWM converter (16A, 16B), the controller (20A, 20B, 50A, 50B) including a vector adder configured to perform vector addition of a part of a voltage drop occurring due to a current flowing through the output impedance (Z1, Z2) and a load voltage command value (ErefL) of the AC load, and a converter configured to output the voltage command value to the PWM converter (16A, 16B) based on a vector sum obtained through the vector addition such that an actual voltage output from each of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) is equal to the voltage command value (Eref1, Eref2), wherein a vector adder configured to perform vector addition of a part of a voltage drop occurring due to a current flowing through the output impedance (Z1, Z2) and a load voltage command value (ErefL) of the AC load, and a converter configured to output the voltage command value to the PWM converter (16A, 16B) based on a vector sum obtained through the vector addition such that an actual voltage output from each of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) is equal to the voltage command value (Eref1, Eref2), wherein the load voltage command values (ErefL) of the plurality of AC output converters (10, 10A, 10B, 11, 11A, 11B) are equal, the controller (20A, 20B, 50A, 50B) includes a vector multiplier (24A, 24B), and the vector multiplier (24A, 24B) is configured to calculate a part of the voltage drop by multiplying a product of a value of the output impedance (Z 1, Z2) and the current flowing through the output impedance (Z1, Z2) by a coefficient smaller than approximately one.