Electric Vehicle Control Device Phase Correction
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Solution Overview
Problem
Transformers equipped with separators to reduce mutual inductance effects are large, heavy, and costly, and existing methods for controlling PWM converters may not sufficiently decrease the harmonic component of the primary current in electric vehicle control systems.
Innovation Solution
An electric vehicle control device with a main transformer and converter controllers that adjust the phase angle of signal and carrier waves based on load operating states, allowing for phase correction of secondary currents without countermeasures for mutual inductance reduction between windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separators are arranged between secondary and tertiary windings to decrease mutual inductance, then the effect of mutual inductance is reduced, but the transformer becomes large in size, heavy in weight, and expensive to manufacture
Solution Approach 1:
The patent replaces the mechanical/physical approach of using separators to reduce mutual inductance with a control system approach. Converter controllers dynamically adjust the phase angles of signal waves and carrier waves used in PWM control, thereby compensating for mutual inductance effects through electronic control rather than physical modification of the transformer structure.
Solution Approach 2:
The patent changes the operational parameters (phase angles) of the converter controllers in response to load operating states. By dynamically adjusting these phase angle parameters, the system compensates for mutual inductance effects without requiring physical separators, thus avoiding the associated weight, size, and cost penalties.
2Ease of operation
If PWM converters are controlled with fixed phase relationships, then control is simple, but harmonic components of primary current are not sufficiently decreased when load operating states vary
Solution Approach 1:
The patent transitions from static fixed phase relationships to dynamic phase angle adjustment. The converter controllers continuously determine and adjust the phase angles of signal waves and carrier waves based on real-time load operating states, enabling the system to adapt to varying conditions while maintaining simple control logic through automated determination of correction amounts.
Solution Approach 2:
The patent implements a feedback mechanism where converter controllers monitor load operating states and use this information to determine appropriate phase angle corrections. This closed-loop control ensures that harmonic components are effectively reduced by continuously adjusting phase relationships in response to actual operating conditions rather than relying on fixed predetermined values.
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
This configuration effectively decreases the harmonic component of the primary current by maintaining phase differences caused by mutual inductance, even without implementing countermeasures for mutual inductance reduction, thus reducing the harmonic component of the primary current.
Implementation Method 1
a main transformer to convert an input AC voltage, input to an input winding from an AC power supply, and to output an output AC voltage converted thereby from each of a plurality of output windings
Implementation Method 2
a plurality of converter main circuits, each connected to one of a plurality of secondary windings included in the plurality of output windings, to convert the output AC voltage, output from the secondary winding connected to the converter main circuit, into a DC voltage
Data Source
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AI summary
An electric vehicle control device (100) includes: a main transformer (102) to convert AC voltage input to an input winding thereof from an AC power source, and output converted AC voltage from each of a plurality of output windings; a plurality of converter main circuits (103), each connected to one of a plurality of secondary windings included in the output windings, to convert AC voltage output from connected secondary windings into DC voltage; and a plurality of converter controllers (111), each targeting for control one of the converter main circuits (103), to control by pulse width modulation the control-target converter main circuit (103), by comparing a signal wave and carrier wave. Each of the converter controllers (111) determines a phase angle correction amount of the signal wave and/or the carrier wave, in response to operating state of a load supplied power through a predetermined output winding among the output windings.