Inverter control device and power conversion device

An inverter control device for controlling an inverter which converts DC power supplied thereto via an LC filter including a reactor and a capacitor into AC power having an intended frequency and an intended voltage value, and supplies the converted power to an AC motor, the inverter control device comprising:

• control calculation sections for calculating an output voltage command;
• an output voltage correction section for directly receiving a DC voltage value from a DC voltage detection section which detects a voltage of DC power supplied to the inverter so as to correct an output voltage command from the control calculation sections based on the DC voltage value;
• a PWM calculation section for calculating a control signal for PWM-controlling the inverter based on an output voltage command from the output voltage correction section;
• a fluctuation component detection section for detecting a fluctuation component (the fluctuation component at least not including a DC component and including a resonance frequency (f0) component of the LC filter) of the DC voltage detected by the DC voltage detection section;
• a link resonance compensation section for calculating an amount of compensation (amount of link resonance compensation) for reducing link resonance due to the LC filter based on the fluctuation component detected by the fluctuation component detection section;
• a limitation section for limiting the amount of link resonance compensation to a predetermined range;
• and
• a correction section for correcting, by the amount of link resonance compensation limited by the limitation section, an input command to one of the compensators in the control calculation section that has such a control band with which it is possible to control the resonance frequency (f0) of the LC filter.

A power conversion device comprising:

• a converter section for converting AC power from an AC power supply into DC power;
• an LC filter including a reactor and a capacitor;
• an inverter section, to which the DC power from the converter section is supplied via the LC filter, for converting the DC power into AC power having an intended frequency and an intended voltage value, and supplying the converted power to an AC motor;
• and
• an inverter control section for controlling the inverter section, wherein
• within a predetermined frequency band of fluctuation of a DC voltage supplied to the inverter, a fluctuation component detection section configured to allow passage of a resonance frequency of the LC filter allows the inverter control section to increase an inverter output voltage supplied from the inverter to a motor when the DC voltage increases, and to decrease the inverter output voltage when the DC voltage decreases, whereas, within a frequency region that is an upper frequency region above the predetermined frequency band of the DC voltage and that is a frequency region of fluctuation when a power supply and a voltage rapidly change and a lower frequency region below the predetermined frequency band, the inverter control section reduces fluctuation of the inverter output voltage due to fluctuation of the DC voltage, the predetermined frequency band of the DC voltage fluctuation including at least the resonance frequency of the LC filter, and being less than or equal to a frequency band of a feedback control in a current controller configured to control such that a current supplied to the AC motor follows a command value.

A power conversion device comprising:

• a converter section for converting AC power from an AC power supply into DC power;
• an LC filter including a reactor and a capacitor;
• an inverter section, to which the DC power from the converter section is supplied via the LC filter, for converting the DC power into AC power having an intended frequency and an intended voltage value, and supplying the converted power to an AC motor;
• and
• an inverter control section for controlling the inverter section, the inverter control section comprising:
• a DC voltage detection section for detecting a voltage of the DC power supplied to the inverter section;
• control calculation sections for calculating an output voltage command;
• an output voltage correction section for directly receiving a DC voltage value detected by the DC voltage detection section so as to correct an output voltage command from the control calculation sections based on the DC voltage value;
• a PWM calculation section for calculating a control signal for PWM-controlling the inverter section based on an output voltage command from the output voltage correction section;
• a fluctuation component detection section for detecting a fluctuation component (the fluctuation component at least not including a DC component and including a resonance frequency (f0) component of the LC filter) of the DC voltage detected by the DC voltage detection section;
• a link resonance compensation section for calculating an amount of compensation (amount of link resonance compensation) for reducing link resonance due to the LC filter based on the fluctuation component detected by the fluctuation component detection section;
• a limitation section for limiting the amount of link resonance compensation to a predetermined range;
• and
• a correction section for correcting, by the amount of link resonance compensation limited by the limitation section, an input command to one of the compensators in the control calculation section that has such a control band with which it is possible to control the resonance frequency (f0) of the LC filter.