Open-Ended Motor Charger Using Phase Windings as Filter Inductors
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Solution Overview
Problem
Existing synchronous electric motor chargers for batteries face issues with torque generation, demagnetization of permanent magnets, increased weight and cost due to external inductors, and complexity in handling single-phase and three-phase power conversions, necessitating a need for an integrated charger that prevents undesirable torque and adapts to either phase type.
Innovation Solution
An integrated synchronous motor charger with open-ended phase windings and a bidirectional inverter, capable of shifting between charging and driving modes, uses soft magnets that can be demagnetized to prevent torque and operate as filter inductors, and includes power decoupling mechanisms to handle single-phase or three-phase power efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If external filter inductors are added to reduce power variations, then improved efficiency is achieved, but weight increases and additional failure points are introduced
Solution Approach 1:
The patent combines the filter inductor function with the motor's existing phase windings by connecting them in series during charging mode. This merging eliminates the need for separate external inductors, reducing weight and component count while maintaining the power filtering function.
Solution Approach 2:
The motor's phase windings serve dual purposes: they function as both the motor's operational windings and as filter inductors during charging. This multi-functionality eliminates redundant components and reduces overall system weight.
2Device complexity
If motor coils are repurposed as inductor filters, then external inductors are eliminated, but torque generation and permanent magnet demagnetization occur
Solution Approach 1:
The patent dynamically controls the motor's magnetic field during charging by adjusting the DC bus voltage to match the battery voltage. This dynamic control prevents torque generation and permanent magnet demagnetization while allowing the phase windings to function as filter inductors.
Solution Approach 2:
The patent changes the operational parameters of the motor during charging mode by applying controlled DC voltage to the phase windings rather than standard AC motor voltage. This parameter change ensures the windings act as inductors without generating harmful torque or demagnetizing the permanent magnets.
3Object-generated harmful factors
If phase windings are center tapped with all nine terminals available, then magnetic fields cancel out and no torque is generated, but effective inductance decreases and current ripples increase
Solution Approach 1:
The patent segments the phase windings into specific series connections during charging mode, using only two terminals per phase winding rather than all nine terminals. This segmentation maintains effective inductance while preventing torque generation.
Solution Approach 2:
The patent uses only a partial configuration of the motor terminals (two per phase) rather than all available terminals. This partial action maintains sufficient inductance for filtering while avoiding the torque cancellation issues of full center-tapping.
4Object-generated harmful factors
If single-phase excitation is used to prevent torque, then a pulsating magnetic field is generated, but power pulses at twice line frequency require additional decoupling electronics
Solution Approach 1:
The patent combines the power decoupling function with the motor's phase windings and the bidirectional inverter. The phase windings serve as both the excitation source and the filtering/decoupling mechanism, eliminating the need for separate decoupling electronics.
Solution Approach 2:
The motor's phase windings self-regulate the power pulses by functioning as filter inductors during single-phase charging. The system uses its own components to decouple the power ripples rather than requiring external decoupling mechanisms.
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 minimizes torque and weight, reduces complexity, and eliminates the need for external inductors, providing efficient and adaptable battery charging with minimal electronics, while supporting both single-phase and three-phase power sources.
Implementation Method 1
a synchronous motor having a set of phase windings... electrically connected to the power source via a bidirectional inverter on a first end of at least one phase winding
Implementation Method 2
The synchronous motor is electrically connected to the battery via a bidirectional inverter... allow electric power to flow bidirectionally between the power source and the battery in the charging mode
Data Source
AI summary
An integrated synchronous motor charger includes a battery, and a synchronous motor having a set of phase windings, with each phase winding thereof having an open-ended winding configuration, the synchronous motor being electrically connected to the battery via a bidirectional inverter on a first end of at least one phase winding from the set of phase windings, and to a power source on a second end of the at least one phase winding. The synchronous motor is operably shiftable between a charging mode and a driving mode, the synchronous motor allowing electric power to flow bidirectionally between the power source and the battery in the charging mode, and allowing electric power to flow bidirectionally between the battery and the synchronous motor in the driving mode.