Power conversion control apparatus

A power conversion system including first and second control systems and a converter, each of said control systems comprising:

• voltage control means for calculating a difference between a voltage detection value and voltage reference value and for amplifying said difference and outputting a voltage control signal;
• margin angle control means for setting a margin angle and tracking the margin angle of said converter to the set margin angle and outputting a margin angle control signal;
• current control means for generating outputting a current control signal, said current control means including,
• an integrating amplifier for outputting an error difference signal between a current reference signal and a detected current value,
• first selection means for selecting between said error difference signal of said first system and said error difference of said second system according to the magnitude and outputting said selected current error difference signal as said current control signal,
• means for applying a correction signal to an input of said integrating amplifier, said correction signal indicating a difference between the output of the integrating amplifier and said selected current error difference signal;
• control advance angle priority means for selecting the control signal which has the most advanced control angle of said current control signal, voltage control signal, and margin angle control signal, and outputting a control advance angle priority signal;
• second selection means for selecting one of the control advance angle priority signals of said first control system and said second control system according to the condition of the control systems and outputting a converter control signal;
• and
• converter control means for controlling the converter in response to said converter control signal.

A method of converting power in a power conversion system including first and second control systems and a converter, comprising the steps of:

• calculating a difference in a voltage control means between a voltage detection value and voltage reference value, amplifying said difference, and outputting a voltage control signal;
• setting a margin angle and tracking the margin angle of said converter to the set margin angle in a margin angle control means and outputting a margin angle control signal;
• calculating a current error difference signal between a current reference signal and a detected current value, amplifying said difference in an integrating amplifier;
• selecting between said error difference signal of said first system and said error difference of said second system according to the magnitude and outputting a selected current error difference signal as a current control value;
• applying a correction signal to an input of said integrating amplifier, said correction signal indicating a difference between the output of the integrating amplifier and said selected current error difference signal;
• selecting the control signal which has the most advanced control angle of said current control signal, voltage control signal, and margin angle control signal in a control advance angle priority means and outputting a control advance priority signal;
• selecting one of said control advance priority signals from the control advance angle priority means of said first control system and of said second control system according to the condition of the control systems and outputting a selected control advance priority signal;
• and
• controlling the converter in response to said selected control advance priority signal.