Drive System Stator Windings as Inductors for Efficient Charging
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Solution Overview
Problem
Existing drive systems for battery-powered vehicles require costly circuits with inductors to efficiently charge energy stores, limiting flexibility in voltage usage and increasing component losses.
Innovation Solution
A compact charging circuit utilizing the stator windings of an electric motor as inductors and an additional energy source, allowing for a wide range of voltage inputs and reducing losses through pulse width modulation and asynchronous control, enabling efficient charging even with fluctuating voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a charging circuit with inductors is used to charge the energy store, then the charging efficiency is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the motor function and charging circuit function into a single system. The stator windings of the motor serve dual purposes: driving the motor and acting as inductors for the charging circuit. This eliminates the need for separate inductor components and reduces overall circuit complexity while maintaining charging efficiency.
Solution Approach 2:
The stator windings are designed to perform multiple functions: they operate as motor windings during motor operation and as inductors during charging operation. This multi-functionality reduces the number of dedicated components needed, simplifying the overall device structure while preserving the energy transfer efficiency of a proper charging circuit.
2Loss of energy
If a charging circuit with inductors is used to charge the energy store, then the charging efficiency is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges the motor structure with the charging circuit components, using the stator windings for both motor operation and as inductors in the charging circuit. This eliminates the need for separate inductor components, reducing part count and manufacturing cost while maintaining charging efficiency.
Solution Approach 2:
The stator windings serve dual purposes as motor windings and charging circuit inductors, eliminating the need for dedicated inductor components. This multi-functionality reduces component procurement costs, assembly costs, and overall manufacturing complexity.
3Power
If the stator windings are used as inductors for the charging circuit, then the voltage level can be increased and compact design is achieved, but the switching frequency increases causing higher switching losses
Solution Approach 1:
The patent employs dynamic control strategies including variable switching frequencies and pulse width modulation (PWM) to optimize the operation of the charging circuit. By dynamically adjusting switching parameters based on operating conditions, the system achieves high voltage conversion while minimizing switching losses through adaptive frequency selection and optimized switching timing.
4Volume of moving object
If the stator windings are used as inductors for the charging circuit, then the device size is reduced, but the ohmic heat losses increase
Solution Approach 1:
The patent combines the motor and charging circuit into a single integrated system, using the stator windings for both purposes. While this achieves compact size, the patent addresses ohmic losses through optimized winding designs, appropriate current distribution strategies, and control methods that minimize resistive heating during charging operation.
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
The solution provides a cost-effective, compact, and efficient charging method that can handle a wide range of voltages, reduces switching and ohmic losses, and allows for simultaneous motor and generator operation, enhancing overall system performance.
Implementation Method 1
at least one stator winding of the electric motor being able to be supplied with a current that can be controlled by a switch, which is supplied from an electrical energy source different from the energy store
Implementation Method 2
the stator windings also at least partially have the function of an additional energy store and also contribute to the smoothing of the charging current
Data Source
Figure 1
AI summary
The invention relates to a drive system and to a method for operating a drive system, comprising an electric motor, inverter, and energy store, wherein the electric motor can be fed by the inverter, and the inverter is supplied from the energy store, wherein at least one stator winding of the electric motor can have current applied thereto controlled by a switch, said current being supplied by an external electrical energy source different from the energy store.