Electric Machine Field Coil Doubles as CSI Inductor
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Solution Overview
Problem
The high cost of drive systems for electric vehicles and wind power generators is driven by the expense of rare earth permanent magnet materials and the need for bulky, temperature-limited capacitors in Voltage Source Inverters, which limits their efficiency and scalability.
Innovation Solution
Integration of an electric machine and a Current Source Inverter (CSI) where the electric machine's field excitation coil doubles as the CSI inductor, reducing the need for capacitors and permanent magnets, thereby minimizing cost, weight, and volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Permanent Magnets are used in electric machines, then the machine performance is improved, but the cost increases significantly due to rare earth materials
Solution Approach 1:
The patent removes permanent magnets from the electric machine design, replacing them with an electromagnet system consisting of field windings and a magnetically conductive rotor. This extraction eliminates dependency on expensive rare earth materials while maintaining the necessary magnetic field generation for machine operation
Solution Approach 2:
The field excitation coil serves dual functions: it generates the magnetic flux required for electric machine operation and simultaneously acts as the inductor for the Current Source Inverter. This multi-functionality reduces the total component count and eliminates the need for separate inductor components, thereby reducing cost and complexity
2Ease of operation
If Voltage Source Inverters are used, then the drive system can operate, but bulky and expensive capacitors are required which are temperature-limited
Solution Approach 1:
The patent inverts the traditional inverter architecture by switching from a Voltage Source Inverter (VSI) that requires large capacitors to a Current Source Inverter (CSI) that uses inductors. This inversion eliminates the need for bulky, temperature-limited capacitors while enabling inverter operation through the use of the field excitation coil as the inductor
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 integration significantly reduces the volume and cost of capacitors, eliminates the need for permanent magnets, and enhances the performance of electric machines and generators, making them more efficient and economically viable for large-scale applications.
Implementation Method 1
uses the electric machine's field excitation coil for not only flux generation in the electric machine
Implementation Method 2
also for the CSI inductor
Data Source
AI summary
A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.