Multi-phase Brushless DC Motor with Independent Windings
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Solution Overview
Problem
Conventional multi-phase brushless DC motors with star-type coil winding configurations result in high power consumption and audible noise due to non-sinusoidal voltage and current outputs.
Innovation Solution
A multi-phase brushless DC motor design featuring independent phase coil windings driven by pulse width-modulated sine waves from a controller, utilizing H-bridge unipolar inverters with a CORDIC algorithm and FPGA, ensuring all windings receive smooth pure sine waves with identical frequency and amplitude, and non-zero phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If star-type coil winding configuration is used, then device complexity is reduced, but power consumption increases and audible noise is generated
Solution Approach 1:
The patent divides the motor into multiple independent phase windings (two-phase, three-phase, or four-phase) instead of using a single star-type configuration. Each phase winding is independently controlled by separate H-bridge unipolar inverters, allowing independent optimization of each phase to reduce overall power consumption and eliminate audible noise through balanced operation.
2Device complexity
If conventional H-bridge inverters with non-sinusoidal output are used, then device complexity is reduced, but audible noise and power consumption increase
Solution Approach 1:
The patent changes the output waveform parameters of the H-bridge unipolar inverters to generate pure sinusoidal voltages with identical frequency and amplitude. This parameter optimization eliminates harmonic content that causes audible noise, while the unipolar configuration maintains relatively simple device structure compared to traditional bipolar bridges.
3Device complexity
If phase coil windings with common terminal are used, then device complexity is reduced, but power harmonic increases
Solution Approach 1:
The patent segments the phase coil windings into independent configurations without common terminals. Each phase winding is independently connected to its own H-bridge inverter, eliminating the harmonic-distorting common terminal connection. This segmentation allows each phase to operate independently with pure sinusoidal current, minimizing total power harmonic content.
4Ease of operation
If trapezoidal or sinusoidal magnetic field orientation control is used, then ease of operation is improved, but power consumption and audible noise increase
Solution Approach 1:
The patent implements a multi-phase universal control system where H-bridge unipolar inverters can operate with different phase configurations (two-phase, three-phase, or four-phase). The system universally applies pure sinusoidal PWM control to all phases simultaneously, achieving efficient commutation with reduced power consumption across all operating modes.
Data Source
AI summary
A multi-phase brushless direct-current motor and a drive method therefor. The motor comprises a motor body and a driving module, and the driving module comprises a controller, a plurality of H-bridge unipolar inverters each of which for a respective phase, and independent phase coil windings (1) which are successively electrically connected. The method comprises: outputting pulse width-modulated sine waves with identical frequency and amplitude from the controller thereby driving respective ones of the plurality of H-bridge unipolar inverters for each phase; wherein the pulse width-modulated sine waves correspond to every two adjacent phase coil windings having a non-zero phase difference, and phase differences of the plurality of phase coil windings are identical; and outputting sine wave driving voltages or sine wave driving currents in their corresponding phases from the respective ones of the plurality of H-bridge unipolar inverters to the corresponding, electrically connected phase coil windings. The multi-phase brushless direct-current motor and the drive method therefor can realize sine-shaped voltage or current driving, thereby improving the efficiency and reducing noise.