JPWO2022149210A5 - - Google Patents

Description

In order to solve the above-described problems and achieve the object, a power conversion device according to the present disclosure includes a rectification unit that rectifies first AC power supplied from a commercial power supply, and a rectification unit that is connected to an output end of the rectification unit. A capacitor, an inverter connected to both ends of the capacitor to generate a second AC power and output it to the motor, a detector for detecting the power state of the capacitor, and a pulsation corresponding to the detected value of the detector to drive the motor. a control unit that controls the operation of the inverter so as to be superimposed on the pattern and suppresses the charging and discharging current of the capacitor. The detection unit detects the charge/discharge current, and the control unit automatically searches for a drive pattern that reduces the pulsation component of a specific frequency contained in the charge/discharge current.

Claims (9)

a rectifier that rectifies first AC power supplied from a commercial power supply;
a capacitor connected to the output terminal of the rectifying unit;
an inverter connected to both ends of the capacitor for generating a second AC power and outputting it to the motor;
a detection unit that detects the power state of the capacitor;
a control unit that controls the operation of the inverter so that the pulsation corresponding to the detection value of the detection unit is superimposed on the drive pattern of the motor, and suppresses the charging and discharging current of the capacitor;
with
The detection unit detects the charge/discharge current,
The power conversion device, wherein the control unit automatically searches for the drive pattern in which a pulsation component of a specific frequency contained in the charge/discharge current is reduced. a rectifier that rectifies first AC power supplied from a commercial power supply;
a capacitor connected to the output terminal of the rectifying unit;
an inverter connected to both ends of the capacitor for generating a second AC power and outputting it to the motor;
a detection unit that detects the power state of the capacitor;
a control unit that controls the operation of the inverter so that the pulsation corresponding to the detection value of the detection unit is superimposed on the drive pattern of the motor, and suppresses the charging and discharging current of the capacitor;
with
The detection unit detects a DC bus voltage that is a voltage across the capacitor,
The power conversion device, wherein the control unit automatically searches for the drive pattern in which a pulsation component of a specific frequency contained in the DC bus voltage is reduced. The control unit
a Fourier coefficient calculator that calculates the amplitude of a component that is included in the deviation between the detected value and the command value or the target value and that corresponds to the power supply frequency of the commercial power supply;
a proportional-integral-derivative control unit for converging the deviation;
an AC restoration unit that restores the output from the proportional-integral-derivative control unit to an AC component and generates a pulsating command for suppressing the charge/discharge current of the capacitor;
The power converter according to claim 1 or 2 , comprising: The detection unit detects an input current flowing from the rectification unit to the capacitor,
The control unit controls the q-axis current command of the motor based on the input/output power relationship of the motor so that the difference between the input current and the output current from the capacitor to the inverter becomes small.
The power converter according to any one of claims 1 to 3. The control unit stores a pulsation pattern for suppressing charging/discharging current of the capacitor, which is set for each operating condition of the load including the motor, and uses the pulsation pattern according to the operating condition of the load. generating a pulsating command for suppressing the charging and discharging current of the capacitor and controlling the operation of the inverter;
The power converter according to any one of claims 1 to 4 . The detection unit detects at least one of a charging/discharging current of the capacitor and a DC bus voltage that is a voltage across the capacitor,
The control unit automatically searches for the pulsation pattern in which a pulsation component of a specific frequency contained in the detection value of the detection unit decreases, and stores the pulsation pattern as the pulsation pattern set for each operating condition.
The power converter according to claim 5 . When the motor drives a load with periodic load torque pulsations,
The control unit suppresses speed pulsation caused by the load torque pulsation.
The power converter according to any one of claims 1 to 6 . A motor drive device comprising the power conversion device according to any one of claims 1 to 7 . A refrigerating cycle application equipment comprising the power converter according to any one of claims 1 to 7 .