Variable Frequency Drive for BLDC Motor Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional BLDC motor control systems face challenges with high PWM switching noise, which causes electromagnetic interference (EMI) and crosstalk, particularly in sensitive applications like gimbal platforms, leading to performance degradation and increased costs due to the need for additional shielding.
Innovation Solution
The implementation of variable generator circuits, such as switching regulators, that generate electrical drive signals based on torque control signals, allowing for adjustable angular speed of the motor without relying on PWM control signals, thereby reducing noise and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If PWM control signals are used to regulate motor torque, then motor speed control is improved, but switching noise and electromagnetic interference increase
Solution Approach 1:
The patent extracts the harmful PWM switching noise from the motor control system by implementing a separate variable frequency drive circuit that generates motor drive signals without using PWM switching. The control system separates torque regulation (via variable frequency drive) from commutation control (via commutation logic circuit), removing the source of electromagnetic interference while preserving speed control functionality.
Solution Approach 2:
The patent introduces a variable frequency drive circuit as an intermediary between the control system and motor windings. This intermediary circuit converts control signals into motor drive signals through a different mechanism that does not rely on high-frequency PWM switching, thereby mediating between the need for speed control and the need to minimize electromagnetic interference.
2Temperature
If high PWM switching frequencies are used to reduce ripple currents in low inductance motors, then heating is reduced, but switching noise and crosstalk increase
Solution Approach 1:
The patent replaces the PWM switching mechanism with a variable frequency drive approach that uses a different physical principle for current regulation. Instead of relying on high-frequency switching and inductive smoothing, the system uses a commutation logic circuit synchronized with rotor position to regulate current flow, eliminating the need for high-frequency PWM switching while maintaining effective ripple current management.
Solution Approach 2:
The patent enables the motor system to self-regulate current flow by synchronizing commutation logic with rotor position feedback. The commutation logic circuit automatically adjusts drive signal timing based on rotor position, allowing the system to manage current ripple and heating without external PWM control, thereby eliminating switching noise while maintaining thermal performance.
3Manufacturing precision
If additional shielding is deployed to avoid crosstalk from motor windings, then signal quality is improved, but space and component cost increase
Solution Approach 1:
The patent converts the harmful electromagnetic interference into a beneficial situation by eliminating its source. By replacing PWM control with a variable frequency drive approach synchronized to rotor position, the system transforms what would have been a noisy environment requiring complex shielding into a clean electromagnetic environment where shielding becomes unnecessary, thereby reducing space and cost while maintaining signal quality.
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 effectively minimizes noise and interference, maintaining performance similar to PWM drive techniques while reducing EMI and shielding requirements, enabling efficient control of electric motors with low inductance, even in sensitive applications.
Implementation Method 1
a plurality of switching regulators, where each of the switching regulators is configured to generate a respective electrical drive signal based on a torque control signal
Implementation Method 2
a commutation logic circuit configured to selectively provide the electrical drive signals of the switching regulators to the windings based on a position of the rotor
Data Source
AI summary
Techniques are disclosed for facilitating control of electric motors. A system includes a brushless direct current (BLDC) electric motor that includes a rotor and windings, where the rotor is configured to rotate with an adjustable angular speed. The system further includes a plurality of switching regulators. Each switching regulator is configured to generate an electrical drive signal based on to a torque control signal, where the angular speed of the rotor is based on the electrical drive signals. The system further includes a commutation logic circuit configured to selectively provide the electrical drive signals of the switching regulators to the windings based on a position of the rotor. To selectively provide the electrical drive signals, the commutation logic circuit may be configured to provide routing control signals provided as six-step commutation signals or motor phase control signals provided as sinusoidal commutation signals. Related systems, devices, and methods are also disclosed.