Motor Control Circuit Sinusoidal Drive Signal Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric motor control circuits for BLDC motors are limited in their ability to provide customizable start-up drive signal characteristics, leading to noise and vibration issues due to the use of trap drive signals, and lack flexibility in accommodating different motor types and loads.
Innovation Solution
A motor controller circuit that generates sinusoidal drive signals with adjustable start-up profiles, synchronized with normal operation, using a small number of pins and low-cost design, to reduce noise and accommodate various motor types by detecting back EMF signals and adjusting drive signals accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If trap drive signals are used during start-up and normal operation, then the motor can be started with a predetermined fixed rate, but audible noise and vibrations occur due to the trap drive signals
Solution Approach 1:
The patent changes the drive signal waveform parameter from trapezoidal to sinusoidal during start-up operation. This parameter change eliminates the abrupt current transitions inherent in trap drives, thereby reducing audible noise and vibrations while maintaining effective motor starting capability across different motor types and load conditions.
Solution Approach 2:
The patent implements dynamic adaptation of the drive signal characteristics by using sinusoidal waveforms with adjustable frequency and amplitude during start-up. This dynamic approach allows the drive signals to be optimized for each specific motor type and load condition, reducing noise and vibration while ensuring reliable motor starting.
2Adaptability or versatility
If a predetermined fixed ramp-up rate is used during start-up, then the motor can be started without BEMF motor position information, but different electric motors require different motor drive signal start-up profiles
Solution Approach 1:
The patent creates a universal start-up drive signal generation method that works across different motor types (BLDC, PMSM, induction motors) and load conditions. By using sinusoidal waveforms with programmable frequency and amplitude characteristics, the system achieves multi-functionality without requiring complex hardware modifications, accommodating various motor inertias and coupled loads through software-controlled parameter adjustment.
3Object-generated harmful factors
If sine drives are used instead of trap drives, then motor noise is reduced, but the drive signals must be synchronized with BEMF signals which are not available until minimum rotating speed is achieved
Solution Approach 1:
The patent applies preliminary action by generating sinusoidal drive signals with predetermined frequency and amplitude characteristics before BEMF information is available. The system pre-configures the drive waveform parameters based on motor specifications, enabling reliable start-up without requiring real-time BEMF feedback during the initial acceleration phase, while still maintaining low noise characteristics.
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 solution effectively reduces motor noise and vibration, provides a customizable start-up profile for different motor types, and ensures efficient operation by synchronizing start-up and normal modes, while maintaining a low-cost and pin-efficient design.
Implementation Method 1
Some sensor-less motor drive arrangements rely upon so-called 'back EMF,' or simply 'BEMF' generated on the motor windings to sense a position of a motor shaft
Data Source
AI summary
A motor control circuit and associated techniques can drive an electric motor in a start-up mode of operation followed by a normal mode of operation. The motor control circuit and techniques can receive a selection signal provided by a user that can select one of a plurality of sets of parameter values that determine characteristics of drive signals applied to the motor during the start-up mode of operation. The motor control circuit and associated techniques can synchronize operation between the start-up mode of operation and the normal mode of operation.