Power converter and a method for controlling a power converter

A method for controlling a power converter that comprises:

• a first terminal connected to a capacitive energy storage,
• a converter circuitry configured to carry out voltage conversion between direct voltage of the first terminal and one or more voltages of a second terminal of the power converter, and
• a control system configured to control the converter circuitry and to control discharge circuits of series connected capacitive elements of the capacitive energy storage to control voltage balance between the capacitive elements based on voltages measured from the capacitive elements, current of the capacitive energy storage, estimates of capacitances of the capacitive elements, and estimates of equivalent serial resistances of the capacitive elements,
• the method comprising:
• controlling the converter circuitry to supply identification current via the first terminal to the capacitive energy storage, and
• computing the estimates of the capacitances and the estimates of the equivalent serial resistances based on i) the identification current as the function of time and ii) changes caused by the identification current in the voltages measured from the capacitive elements.

A non-volatile computer readable medium encoded with a computer program for controlling a power converter that comprises:

• a first terminal connected to a capacitive energy storage,
• a converter circuitry configured to carry out voltage conversion between direct voltage of the first terminal and one or more voltages of a second terminal of the power converter, and
• a control system configured to control the converter circuitry and to control discharge circuits of series connected capacitive elements of the capacitive energy storage to control voltage balance between the capacitive elements based on voltages measured from the capacitive elements, current (i) of the capacitive energy storage, estimates of capacitances of the capacitive elements, and estimates of equivalent serial resistances of the capacitive elements,
• the computer program comprising computer executable instructions for controlling a programmable data processing system of the control system to:
• control the converter circuitry to supply identification current via the first terminal, and
• compute the estimates of the capacitances and the estimates of the equivalent serial resistances based on i) the identification current as the function of time and ii) changes caused by the identification current in the voltages measured from the capacitive elements.