Motor Controller Circuit Sine Drive Signal Generation
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Solution Overview
Problem
Existing electric motor control circuits for BLDC motors are limited in their ability to adjust start-up drive signal characteristics and synchronize them with normal operation, leading to noise and vibration issues due to the use of trap drive signals, and they require more pins and are not cost-effective for generating sine drive signals.
Innovation Solution
A motor controller electronic circuit that uses a small number of pins, is low-cost, and generates sine drive signals instead of trap drive signals, providing a synchronized start-up and normal mode operation with reduced noise, suitable for various types of electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If trap drive signals are used to start the motor, 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 waveform parameter from trapezoidal to sinusoidal drive signals. This parameter change eliminates the abrupt transitions inherent in trap drives, thereby reducing audible noise and vibrations while maintaining effective motor starting capability.
Solution Approach 2:
Instead of using the conventional trap drive approach that causes noise, the patent inverts the approach by using sinusoidal drive signals which naturally produce smoother current transitions and eliminate the harmful noise and vibration effects.
2Object-generated harmful factors
If a motor controller integrated circuit is designed to generate sine drive signals with adjustable start-up profiles, then noise is reduced, but the number of pins and circuit complexity increase
Solution Approach 1:
The motor controller integrated circuit is designed with multi-functionality to perform both start-up and normal operation modes using the same sinusoidal drive generation circuitry. This universal design eliminates the need for separate complex circuits, thereby reducing pin count and overall device complexity while maintaining noise reduction benefits.
Solution Approach 2:
The patent implements dynamic adjustability of start-up profiles through software or register-based control rather than hardware switches. This allows multiple start-up characteristics to be selected without adding physical pins, reducing device complexity while providing the needed adaptability for different motor types.
3Duration of action of stationary object
If trap drive signals are used during normal mode operation, then the motor operates continuously, but noise remains prominent even with low duty cycles
Solution Approach 1:
The patent changes the drive signal waveform parameter from trapezoidal to sinusoidal for normal mode operation. This parameter change maintains continuous motor operation while eliminating the prominent noise associated with trap drive signals, even at low duty cycles.
4Reliability
If a fixed and predetermined ramp-up rate is used during start-up, then the motor can be started without BEMF information, but different motor types require different start-up profiles
Solution Approach 1:
The patent implements dynamic adjustability of the sinusoidal drive parameters including ramp-up rate, frequency, and amplitude through software or register-based control. This allows the same hardware circuit to adapt to different motor types (BLDC, PMSM, induction) while maintaining reliable start-up without BEMF information.
Solution Approach 2:
The patent enables parameter changes in the sinusoidal drive signals to accommodate different motor characteristics. By adjusting frequency, amplitude, and ramp-up rate parameters, the system can optimize performance for various motor types while maintaining the reliability of starting without back-EMF sensing.
Data Source
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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.