ECM Motor Speed Range Extension via Advance Angle Control
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Solution Overview
Problem
Existing methods for increasing the rotational speed range of ECM motors are complex and resource-intensive, requiring high computational power and accurate rotor position and phase current information, leading to high production costs and operational complexity.
Innovation Solution
The method employs advance angle control, using a microprocessor to calculate and regulate an advance angle based on DC bus current and rotational speed, simplifying calculations and reducing microprocessor load, and incorporating a PWM signal to control the inverter circuit and achieve target rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If vector flux weakening control is used to increase rotational speed, then the maximum rotational speed is improved, but the device complexity and microprocessor requirements increase tremendously
Solution Approach 1:
The patent extracts and eliminates the complex coordinate transformation and vector control calculations from the control system. Instead of implementing full vector flux weakening control requiring Id and Iq current calculations, the invention uses only the basic PWM voltage equation U=F(V_D, θ+α) with advance angle control, removing unnecessary computational complexity while maintaining speed extension capability
Solution Approach 2:
The patent changes the control parameter from complex vector currents (Id, Iq) to a simplified advance angle α that is calculated based on DC bus current I and rotational speed n through the function α=F(I, n). This parameter transformation simplifies the control logic and reduces computational requirements while achieving the same speed extension objective
2Speed
If vector flux weakening control is implemented, then rotational speed range is increased, but production cost increases due to high microprocessor requirements
Solution Approach 1:
The patent replaces expensive high-performance microprocessors required for vector control with simpler, lower-cost microprocessors that can handle basic PWM generation and advance angle calculation. The simplified control algorithm using α=F(I, n) requires minimal computational resources, allowing the use of more economical hardware components while maintaining the ability to extend rotational speed range
3Measurement precision
If accurate rotor position and phase current information are used for control, then speed regulation precision is improved, but operation complexity increases
Solution Approach 1:
The patent extracts and removes the requirement for accurate phase current information from the control system. Instead of measuring and processing three-phase currents to calculate Id and Iq, the invention uses only DC bus current I measurement combined with rotor position θ from Hall sensors to calculate the advance angle, significantly simplifying the measurement and operation requirements while maintaining control precision
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 simplifies the control process, decreases production costs, and enables faster and more reliable achievement of target rotational speeds while protecting the motor from excessive currents and speeds, thereby broadening the rotational speed range effectively.
Implementation Method 1
the hall sensor inputs a rotor position signal to the microprocessor and converts the rotor position signal into a real rotational speed n of the rotor
Implementation Method 2
calculating a PWM signal input into the inverter circuit by the microprocessor; outputting a PWM chopper voltage U by the inverter circuit
Data Source
AI summary
A method for increasing rotational speed range of an ECM motor, including: 1) starting the motor and initializing parameters; 2) reading the rotor position signal from the hall sensor by the microprocessor and updating the rotor angle; 3) reading the DC bus current I and the rotational speed n of the motor; 4) inputting a target rotational speed S from an external device, acquiring the target rotational speed S by the microprocessor, calculating the rotational difference e, and utilizing a rotational speed PI regulator to output a regulating parameter V_D; 5) calculating an advance angle α=F(I, n) by the microprocessor, and calculating a real-time angle of the rotor θ=ω×t by the microprocessor; and 6) calculating a PWM signal input into the inverter circuit, and outputting a PWM chopper voltage U by the inverter circuit, where U=F(V_D, θ+α).