Motor Drive Inverter Control for Vibration and Harmonic Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power conversion apparatuses fail to prevent an increase in harmonic components of the power-supply current when compensating for torque pulsation in motors, leading to imbalances and increased harmonics.
Innovation Solution
A power conversion apparatus with a control device that includes an excitation current compensation unit and an excitation current compensation limiting unit, which reduces pulsation of the capacitor output current and limits the excitation current compensation value to prevent harmonic component increases in the power-supply current, while compensating for torque pulsation in motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If excitation current compensation is applied to reduce torque pulsation, then vibration of the load is reduced, but harmonic components of the power-supply current increase
Solution Approach 1:
The system dynamically adjusts the excitation current compensation based on the operating state of the motor. The control device calculates optimal compensation values that vary with motor speed and load conditions, allowing the system to reduce vibration while preventing excessive harmonic generation across different operating points
Solution Approach 2:
The patent changes the parameters of excitation current compensation to optimize the balance between vibration reduction and harmonic control. By adjusting compensation magnitude and frequency characteristics based on motor operating state, the system achieves vibration reduction without causing excessive harmonic distortion in the power supply current
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents harmonic component increases in the power-supply current, maintaining balance and reducing vibrations in motor-driven loads, thus enhancing the efficiency and reliability of the power conversion process.
Implementation Method 1
a converter that rectifies a power-supply voltage applied from an AC power supply
Implementation Method 2
a capacitor connected to an output end of the converter
Implementation Method 3
an inverter that converts a DC voltage output from the capacitor into an AC voltage and applies the AC voltage to the motor
Implementation Method 4
a control device that performs vibration reduction control of reducing vibration of the load by controlling an operation of the inverter
Implementation Method 5
an excitation current compensation unit that reduces pulsation of a capacitor output current output from the capacitor to the inverter
Data Source
AI summary
A power conversion apparatus includes: a converter that rectifies a power-supply voltage applied from an AC power supply; a capacitor connected to an output end of the converter; an inverter connected across the capacitor; and a control device that performs vibration reduction control of reducing vibration of a compressor by controlling an operation of the inverter. The control device includes: a γ-axis current compensation unit that reduces pulsation of a capacitor output current output from the capacitor to the inverter; and a γ-axis current compensation limiting unit that limits an excitation current compensation value generated by the γ-axis current compensation unit so as to reduce a harmonic component included in a power-supply current flowing between the AC power supply and the converter.