Variable Magnetization Machine Controller Inverter Voltage Limit
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Solution Overview
Problem
At high motor speeds, the voltage induced by pulse currents in variable magnetization machines becomes too high for the inverter to maintain sufficient voltage, limiting the motor's operational speed.
Innovation Solution
A controller system that generates a reverse rotating d-axis/q-axis current vector trajectory, reducing the voltage induced by pulse currents through elliptical current trajectories, allowing the inverter to provide sufficient voltage even at high speeds by managing the magnetization state and current pulses effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor speed is increased, then the performance of the variable magnetization machine is improved, but the voltage induced by pulse current increases to a level that the inverter can no longer provide sufficient voltage
Solution Approach 1:
The patent applies reverse rotation of the current vector trajectory to counteract the harmful effects of high-speed operation. By rotating the current vector in the opposite direction (reverse rotating d-axis/q-axis current vector trajectory), the system reduces the induced voltage and prevents excessive voltage buildup that would otherwise limit motor speed. This inversion approach allows the inverter to maintain sufficient voltage control even at high speeds.
Solution Approach 2:
The patent changes the magnetization state of the variable magnetization machine to optimize performance at different operating conditions. By manipulating the magnetization level dynamically, the system can adjust its magnetic properties to reduce induced voltage at high speeds while maintaining torque capability. This parameter change enables the motor to operate effectively across a wider speed range without exceeding inverter voltage capabilities.
2Speed
If the current pulse width is shortened to increase ramp rate, then the current response speed is improved, but the voltage induced in the control system increases
Solution Approach 1:
The patent uses reverse rotating current vector trajectories to counteract the voltage induced by fast current pulses. By implementing the reverse rotation control strategy, the system can maintain short current pulse widths for fast response while the reverse rotation effect reduces the net induced voltage, preventing it from reaching levels that would limit inverter capability.
3Force
If the magnetization level is increased to increase torque, then the torque output is improved, but the voltage requirements increase
Solution Approach 1:
The patent dynamically adjusts the magnetization state to optimize the torque-voltage tradeoff. By changing the magnetization level based on operating conditions, the system can achieve high torque output when needed while managing the associated voltage requirements. The reverse rotating current vector trajectory further helps to reduce induced voltage, allowing higher magnetization levels to be used without exceeding inverter voltage capabilities.
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
Enables the inverter to maintain sufficient voltage at high motor speeds by reducing the induced voltage, ensuring stable operation of the variable magnetization machine.
Implementation Method 1
the voltage induced by a pulse current to control a variable magnetization machine, such as an electric motor
Data Source
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AI summary
A variable magnetization machine control system comprising a controller (100) configured to generate a reversely rotating d-axis/q-axis current vector trajectory during a change in a magnetization state of a variable magnetization machine (10) to drive the variable magnetization machine (10) at a predetermined speed while maintaining the driving voltage below a predetermined maximum magnitude.