Electric Machine Power Map Control for Current Spike Prevention
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Solution Overview
Problem
Existing electric machine control systems face challenges in efficiently adjusting power in response to varying input signals, particularly in managing power supply changes and accessory demands, which can lead to inefficiencies and excessive current spikes.
Innovation Solution
The method involves storing power maps with control values for different power levels, selecting appropriate maps based on input signals, and using advance and freewheel times to control winding excitation, thereby managing power and efficiency across a range of voltages and speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single power map is used for all operating conditions, then the control system is simple, but the efficiency and power control precision deteriorates across varying voltages and speeds
Solution Approach 1:
The control system divides the operating range into multiple segments by storing multiple power maps, each optimized for specific voltage and speed ranges. The controller selects the appropriate power map based on current operating conditions, ensuring optimal efficiency across the entire operating range rather than using a single generic map.
Solution Approach 2:
The control system dynamically adapts to changing operating conditions by selecting different power maps based on real-time voltage and speed measurements. This dynamic adaptation allows the system to maintain high efficiency across varying operating conditions rather than being fixed to a single control strategy.
2Power
If power is increased to meet accessory demands, then the power output is sufficient, but excessive current spikes occur that can damage the power supply
Solution Approach 1:
The controller proactively monitors power supply voltage and accessory demands before excessive current spikes occur. By selecting appropriate power maps in advance based on predicted power requirements, the system prevents harmful current spikes rather than reacting after damage occurs.
Solution Approach 2:
The control system continuously monitors operating conditions including voltage, speed, and accessory demands, using this feedback to dynamically select the most appropriate power map. This closed-loop control ensures power output meets demands while preventing harmful current spikes by adjusting control parameters in real-time.
3Device complexity
If the excitation timing is not optimized for varying voltages, then the control is simple, but the efficiency and power output deteriorate
Solution Approach 1:
Each power map contains optimized excitation timing parameters specifically tuned for certain voltage and speed ranges. By changing the control parameters (excitation timing) based on operating conditions through map selection, the system maintains high efficiency and power output across the entire operating range.
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 allows for precise control of electric machine power and efficiency, maintaining constant output power and high efficiency (≥75%) across a broad range of voltages and speeds, preventing excessive current spikes and optimizing performance.
Implementation Method 1
an electric machine, the method comprising: storing a plurality of power maps, each power map comprising control values for driving the electric machine at different power
Implementation Method 2
The winding is excited in advance of zero-crossings of back emf in the winding by an advance time that is defined by the first control value
Data Source
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AI summary
A method of controlling an electric machine, the method comprising storing a plurality of power maps, each power map comprising control values for driving the electric machine at different power, and selecting a power map in response to an input signal. Additionally, a control system for an electric machine, and a product incorporating the control system and electric machine.