Pseudo-sinusoidal Motor Control Reducing Noise and Compute Load
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing synchronous electric motor control methods require significant computing resources for sinusoidal control, leading to high costs and complexity, or generate noise with trapezoidal control.
Innovation Solution
A pseudo-sinusoidal control method that generates three control signals with varying pulse durations, using pulse width modulation to create a supply current shape close to sinusoidal without needing a dedicated signal processing processor, reducing noise and computational requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sinusoidal control current is generated based on real-time rotor position and current measurements, then proper motor operation is ensured, but significant computing resources are required including complex mathematical transformations and dedicated DSP units
Solution Approach 1:
The control method segments the sinusoidal control current generation into discrete control ranges, each associated with a predefined interval of rotor angular positions. For each control range, specific control signals with predetermined modulation duty cycles are applied, eliminating the need for continuous real-time calculations while maintaining proper motor operation across all positions.
Solution Approach 2:
The invention pre-calculates and stores control signals with specific modulation duty cycles for each control range before actual motor operation. This preliminary preparation allows the controller to simply retrieve and apply pre-determined control parameters based on the current control range, without performing complex real-time mathematical transformations.
2Device complexity
If trapezoidal supply current is used to simplify control calculation, then computing resources are reduced, but the motor generates high noise during operation due to abrupt reversals in supply current
Solution Approach 1:
The invention applies different modulation duty cycle characteristics to different control ranges. Within each control range, the first and second control signals have modulation duty cycles that vary inversely, while the third control signal maintains a constant modulation duty cycle. This localized differentiation produces a pseudo-sinusoidal current waveform that is smooth and noise-free while keeping control calculations simple.
3Reliability
If sinusoidal control is implemented with dedicated DSP units, then proper motor operation is achieved, but the cost and manufacturing complexity of the motor control system increases
Solution Approach 1:
The invention extracts the complex signal processing functionality from dedicated DSP units and implements it through a simplified control method using basic microcontroller capabilities. By removing the requirement for specialized hardware and using only standard control components, the manufacturing complexity and cost are significantly reduced while maintaining proper motor operation.
4Object-generated harmful factors
If pseudo-sinusoidal control with varying duty cycles is used, then noise is reduced and computing resources are lowered, but the control system must manage multiple control ranges and inverse duty cycle variations
Solution Approach 1:
The invention introduces dynamic adjustment of modulation duty cycles within each control range, where the duty cycles of the first and second control signals vary inversely to produce a pseudo-sinusoidal waveform. This dynamic control is confined to discrete control ranges rather than continuous operation, simplifying the overall management while achieving noise reduction.
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
The pseudo-sinusoidal control method achieves efficient motor operation with reduced noise and computational resources, suitable for high-torque or low-voltage applications, without the need for expensive signal processing hardware.
Implementation Method 1
generation of electric supply currents to power a synchronous electric motor, each powering a winding of the motor and being generated by pulse width modulation from the control signal which is associated with that winding
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The pseudo-sinusoidal control method for controlling a synchronous electric motor comprises steps of a) generating (104) three control signals, each having a plurality of pulses, b) generating (106) electrical currents for powering a synchronous electric motor, each powering a motor winding and being generated by pulse width modulation from the control signal associated with this winding, while, in step a), the three control signals are generated for consecutive control ranges, each associated with a predetermined range of angular positions of a rotor of the motor; the method is characterised in that the pulses of the control signals generated in step a) have a duration that varies over the consecutive control ranges, such that, for each control range, the respective modulation duty cycle values of first and second control signals selected for this control range from the three generated control signals vary inversely in relation to the other, the third control signal having a constant value.