Multi-Phase Motor Harmonic Injection for Torque and Loss Balance
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Solution Overview
Problem
Existing motor and generator systems, particularly induction machines, do not fully utilize harmonic injection techniques to improve efficiency and torque density, as these techniques have primarily focused on voltage capability and torque density for permanent magnet motors, leaving other performance indexes uninvestigated.
Innovation Solution
Implementing a field-oriented harmonic injection control mechanism that injects high-order harmonics into motor windings, configuring them as synchronous harmonic currents to enhance torque and efficiency, with adjustable injection ratios based on performance indexes such as torque, power loss, and system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-order harmonic currents are injected into motor windings to increase torque density, then the torque output is improved, but magnetic saturation may occur in the motor core
Solution Approach 1:
The patent applies parameter changes by injecting high-order harmonic currents with specific amplitude ratios and phase angles into the motor windings. The controller dynamically adjusts the harmonic injection ratios based on operating conditions to maximize torque density while maintaining magnetic flux density within saturation limits. This resolves the contradiction by changing the electrical parameters (current harmonics) to achieve higher torque without causing magnetic saturation.
2Power
If high-order harmonic currents are injected to improve torque, then the torque output increases, but power loss in the motor increases
Solution Approach 1:
The controller dynamically adjusts the harmonic injection ratios as operating parameters change, optimizing the balance between torque output and power loss. By carefully selecting the amplitude and phase of injected harmonics, the system achieves improved torque density while minimizing additional copper losses and core losses, thus resolving the energy loss contradiction.
Solution Approach 2:
The system employs dynamic control where the harmonic injection ratios are continuously adjusted based on real-time operating conditions (speed, load, temperature). This dynamic adaptation allows the motor to operate at optimal efficiency points across different operating ranges, preventing excessive power loss while maintaining high torque output capability.
3Power
If traditional harmonic injection techniques are used to improve voltage capability, then the inverter voltage utilization is improved, but the impact on other performance indexes such as efficiency and power loss is not optimized
Solution Approach 1:
The patent extends traditional harmonic injection by injecting multiple high-order harmonics (5th, 7th, 11th, 13th, etc.) with specifically optimized amplitude ratios and phase angles. This multi-harmonic approach, controlled through field-oriented control, simultaneously improves voltage capability and optimizes efficiency by accounting for the impact of each harmonic on power loss and torque production, resolving the contradiction between voltage utilization and overall system efficiency.
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 approach significantly improves the operational performance of motor drive systems by increasing torque density, reducing power loss, and optimizing system efficiency, while avoiding excessive magnetic saturation and rotor slip.
Implementation Method 1
a motor having a plurality of windings, a rotor and a stator magnetically coupled to the rotor
Data Source
AI summary
A system includes a motor having a plurality of windings, a rotor and a stator magnetically coupled to the rotor, a plurality of power inverters connected to respective windings, wherein the plurality of power inverters is configured to control currents of the plurality of windings, and a controller configured to determine an injection ratio of a high-order harmonic component to a fundamental component based on a performance index, and wherein the injection ratio for a magnetizing component is different from the injection ratio for a torque component at a same harmonic frequency.