Current control device and power conversion system employing same

A power conversion system, comprising:

• a power grid, an inverter, and N power conversion unit(s) connected to each other, wherein N is an integer greater than or equal to 1, the N power conversion units being connected in parallel when N is greater than 1, each of the N power conversion unit(s) comprising a signal input terminal and a current-controlled output terminal electrically connected to an external circuit;
• and
• a current control device configured to provide current command(s) to the N power conversion unit(s) for controlling current(s) flowing through the N power conversion unit(s), wherein the current control device comprises:
• a first current sensor coupled between the current-controlled output terminal and the external circuit, to sample a current flowing through the external circuit and to acquire a current sampling value;
• and
• an error compensator electrically connected to the N power conversion unit(s) and the first current sensor, wherein the error compensator receives the current sampling value and a current reference value and generates a compensation value accordingly, and wherein the error compensator outputs N current command(s) to the N power conversion unit(s) respectively according to the current reference value and the compensation value,
• wherein the error compensator comprises a compensation unit and a calculation unit, the compensation unit generates the compensation value according to the current sampling value and the current reference value, and wherein the calculation unit outputs the N current command(s) to the N power conversion unit(s) according to the current reference value and the compensation value.

A current controller to control a power converter having a first terminal and a second terminal electrically connected to an external circuit, the current controller comprising:

• a first current sensor coupled between the second terminal and the external circuit to acquire a current sampling value associated with a current flowing through the external circuit;
• and
• an error compensator electrically connected to the power converter and the first current sensor, wherein the error compensator receives the current sampling value from the first current sensor and generates a compensation value based on the current sampling value and a current reference value, and wherein the error compensator outputs to the power converter a current command calculated based on the current reference value and the compensation value,
• wherein the error compensator comprises a compensation unit and a calculation unit, the compensation unit generates the compensation value according to the current sampling value and the current reference value, and wherein the calculation unit outputs the calculated current command to the power converter according to the current reference value and the compensation value.