Three-Phase Transformer With Unique Phase Angles For Harmonic Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional variable frequency drive (VFD) systems experience high harmonic currents due to their nonlinear load characteristics, which are exacerbated by the 2× pulse characteristic of conventional designs, leading to operational inefficiencies and harmonic issues in three-phase applications.
Innovation Solution
The implementation of a three-phase transformer circuit with a secondary winding phase angle scheme that increases the number of current pulses to greater than two times the number of converter/inverter modules, achieving advanced harmonic current quashing (AHQ) by using a magnetic core with primary and secondary windings configured to produce unique phase angles for each output, thereby reducing harmonic currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional VFD designs with standard transformer configurations are used, then the device complexity is low, but harmonic currents increase and pulse number is limited to 2× the number of converter/inverter modules
Solution Approach 1:
The transformer is divided into multiple secondary windings (at least three) with different winding turns, where each secondary winding provides a distinct phase angle. This segmentation allows the system to generate multiple current pulses with different phase relationships, thereby reducing harmonic currents through phase cancellation effects while maintaining manageable complexity in each individual winding.
Solution Approach 2:
The invention changes the winding turns parameter of secondary windings to create different phase angles. By adjusting the number of turns in each secondary winding relative to the primary winding, the system generates specific phase shifts (e.g., 30°, 60°, 90°) that multiply the pulse number and reduce harmonic content. This parameter modification transforms the standard transformer output into a harmonic-reducing multi-pulse configuration.
2Productivity
If the number of secondary windings with unique phase angles is increased, then the pulse number increases to greater than 2×, but the transformer design complexity increases
Solution Approach 1:
The invention systematically varies the winding turns parameter across secondary windings to generate discrete phase angles. By establishing a mathematical relationship between turns ratio and phase angle, the system achieves high pulse numbers (greater than 2×) through controlled parameter variation rather than complex structural arrangements, making the design scalable and manufacturable.
3Object-generated harmful factors
If standard transformer configurations are used, then manufacturing is simple, but harmonic current reduction is insufficient
Solution Approach 1:
The invention modifies the winding turns parameter in a systematic manner to achieve harmonic reduction. Each secondary winding's turns are calculated based on desired phase angle requirements, creating a repeatable manufacturing process. This parameter-based approach allows standard winding techniques to be used while achieving advanced harmonic current quashing, bridging the gap between manufacturability and performance.
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 significantly reduces harmonic currents and increases the number of current pulses, resulting in a substantial decrease in harmonic occurrences within the VFD system, enhancing operational efficiency and power input characteristics.
Implementation Method 1
a primary winding placed around the magnetic core and having three primary winding leads to which a three phase power supply can be connected; and a plurality of secondary windings placed around the magnetic core in a predetermined winding turns configuration to generate a plurality of three phase outputs
Data Source
AI summary
A power supply device comprising an advanced harmonic current quashing (AHQ) and current pulse multiplier (CPM) (AHQ/CPM) three-phase transformer having: a primary winding placed around a magnetic core and having three primary winding input leads to connect a three phase power supply; and a plurality of secondary windings placed around the magnetic core in a predetermined winding turns configuration to generate a plurality of three phase outputs, where each three phase output of the plurality of three phase outputs has a different phase angle from all other three phase outputs, with each unique phase angle associated with a three phase output of a corresponding secondary winding being determined based on the winding turns configuration utilized for the corresponding secondary winding. A variable frequency drive (VFD) having 3N converters/inverters coupled to the secondary windings outputs exhibit substantially reduced harmonic currents and a current pulse number of greater than 6N.