Boost Converter Energy Recovery for Fast Pulsed Motor Control
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Solution Overview
Problem
Electric machines, such as motors and generators, operate at varying efficiency levels based on load conditions, with most efficient operation occurring within specific speed and torque ranges, leading to reduced efficiency outside these ranges, particularly in applications like battery-powered electric vehicles where extended range is desirable.
Innovation Solution
Implementing a pulsed control system with a power converter and boost circuit that reduces rise and fall times of pulsed power by extracting magnetic energy from the machine at the end of a pulse and storing it for the beginning of the next pulse, improving overall efficiency by maintaining operation near peak efficiency levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pulsed power is applied to the electric machine without a boost circuit, then the machine can operate in pulsed mode to improve efficiency at certain load conditions, but the rise and fall times of the pulses are prolonged causing energy losses during transition periods
Solution Approach 1:
The boost circuit performs preliminary action by storing energy in the magnetic field before the pulse transition begins. When a pulse edge occurs, the pre-stored energy is immediately released to the stator windings, eliminating the delay that would otherwise be required to build up the magnetic field from scratch. This preliminary energy storage resolves the contradiction by maintaining fast rise/fall times while operating in pulsed mode.
Solution Approach 2:
The system employs periodic pulsed action with controlled duty cycles to operate the electric machine. By switching between pulsed and continuous operation based on load conditions, the system achieves high efficiency at partial loads through pulsing while maintaining adequate performance across the full operating range. The periodic nature of the pulses, combined with the boost circuit's energy recycling, resolves the time loss contradiction.
2Adaptability or versatility
If the electric machine operates outside its peak efficiency speed and torque ranges, then it can meet varying load demands, but the energy conversion efficiency decreases significantly
Solution Approach 1:
The system dynamically adjusts its operating mode between continuous and pulsed operation based on real-time load conditions. The controller monitors the electric machine's operating point and switches to pulsed mode with boost circuit assistance when operating outside the peak efficiency region, thereby dynamically optimizing efficiency while maintaining the ability to meet varying load demands. This dynamic adaptation resolves the contradiction between versatility and efficiency.
Solution Approach 2:
The system changes key operating parameters including pulse duty cycle, frequency, and voltage levels to maintain optimal efficiency across different load conditions. By adjusting these parameters dynamically, the electric machine can operate efficiently even when speed and torque requirements fall outside the peak efficiency region. The boost circuit enables rapid parameter changes without energy loss, resolving the contradiction.
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 enhances the energy conversion efficiency of electric machines by minimizing time spent in less efficient transition periods and optimizing torque delivery, thereby extending the operational range of electric vehicles on a given battery charge.
Implementation Method 1
The boost circuit extracts at least some of a magnetic energy present in the electric machine at the end of a pulse
Implementation Method 2
a power converter coupled between the power supply and the electric machine. The power converter is arranged to provide pulsed input power to the windings of the stator
Data Source
AI summary
A boost circuit is arranged to reduce rise and fall times of pulsed power used for pulsed control operation of electric machines. Magnetic energy present in the electric machine at the end of a pulse is extracted by the boost circuit to reduce the pulse fall time. The energy is stored by the boost circuit and then applied at the beginning of a subsequent pulse to reduce the rise time. By reducing rise and fall times compared to not using such a boost circuit, machine efficiency is improved.