Power Converter Control for DC Voltage Pulsation Suppression

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Solution Overview

Problem

Existing power converter systems face challenges in suppressing the pulsation component of DC voltage, which leads to inefficiencies and noise in electrical motor driving devices.

Innovation Solution

A control device for a power converter that includes a pulsation component detection unit and a control circuit, which adjusts the load angle of a synchronous electrical motor in response to the instantaneous value of the pulsation component, thereby controlling the output power to suppress the amplitude of the pulsation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the inverter switches to convert DC voltage to AC voltage, then the motor can be driven, but the DC voltage pulsation component increases

Engineering Contradiction:
Improvemotor driving capabilityVSAvoidDC voltage stability
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The control device detects the pulsation component of the DC voltage and feeds back control signals to the inverter to adjust its switching timing. This feedback mechanism allows the system to dynamically compensate for voltage pulsations while maintaining motor driving capability, resolving the contradiction between power conversion function and voltage stability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control device applies periodic correction to the inverter switching based on the detected pulsation pattern. By synchronizing the correction with the pulsation frequency, the system effectively reduces DC voltage pulsation while maintaining continuous motor operation, addressing the contradiction between periodic switching necessity and voltage stability.

Inventive Principle:
Principle #19Periodic action

2Power

If the pulsation component amplitude increases, then more power can be transmitted, but motor noise increases

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidmotor noise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The control device converts the harmful pulsation effect into a beneficial control signal. By detecting the pulsation component and using it to adjust inverter switching timing, the system transforms what would be noise-causing vibrations into a controlled parameter that actually improves power transmission efficiency while reducing noise through active compensation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If conventional control methods are used, then the system structure remains simple, but the pulsation component cannot be suppressed

Engineering Contradiction:
Improvecontrol system structureVSAvoidDC voltage pulsation suppression
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The control device integrates multiple functions into a single unit: it detects pulsation components, processes control signals, and adjusts inverter switching all through one control circuit. This multi-functional approach suppresses DC voltage pulsation without requiring separate complex subsystems, resolving the contradiction between structural simplicity and pulsation suppression capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3522363B1Control device for power converter
Publication Date: 2024.01.10 DAIKIN INDUSTRIES LTD
  • EP3522363B1 patent drawingFigure 1
  • EP3522363B1 patent drawingFigure 2~3
  • EP3522363B1 patent drawingFigure 4

AI summary

The present invention is a control device for a power converter capable of suppressing a pulsation component of a DC voltage. A power converter converts a DC voltage (Vdc) including a pulsation component (Vdch) into an AC voltage and outputs the AC voltage to a synchronous electrical motor. A control device for controlling the power converter includes a pulsation component detection unit (6) and a control circuit (3). The pulsation component detection unit (6) detects a pulsation component (Vdch). The control circuit (3) controls the power converter so that a load angle of the synchronous electrical motor is increased in accordance with increase in an instantaneous value of the pulsation component (Vdch).