Motor End Winding PCB with Transient Voltage Suppression
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Solution Overview
Problem
High power density motors face challenges in reducing losses due to connections between windings and external components, which increase resistance and size, and conventional methods like soldering or brazing negate the benefits of multi-strand wire constructions, while existing lightning strike protection in motor drives adds complexity, weight, and cost.
Innovation Solution
Incorporating transient voltage suppression components onto the end winding PCB, allowing for compact motor design and relocating functions from the motor drive to the PCB, which provides electrical isolation and reduces losses by using a heavy copper PCB for connections without soldering or brazing, enabling efficient lightning strike protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering or brazing is used to connect windings, then electrical connection is achieved, but resistance increases and losses are introduced
Solution Approach 1:
The patent extracts the harmful soldering/brazing process from the connection method and replaces it with direct mechanical connection through PCB pads. The windings are connected to copper pads on the PCB without any intermediate soldering or brazing, eliminating the resistance increase and energy losses associated with these thermal joining processes.
Solution Approach 2:
The PCB acts as an intermediary component that provides low-resistance electrical connections between different windings and external components. The heavy copper PCB with large copper pads serves as a mediator that maintains electrical continuity without requiring soldering or brazing, thus avoiding the associated resistance penalties.
2Loss of energy
If multi-strand wire is used for windings, then eddy current losses are reduced, but connection complexity increases
Solution Approach 1:
The patent extracts the connection complexity from the multi-strand wire assembly by providing a dedicated PCB connection interface. The PCB with its copper pads and traces handles the complexity of connecting multiple strands, allowing the multi-strand wire to maintain its low eddy current loss characteristics while the connection task is delegated to the PCB structure.
3Reliability
If lightning strike protection is provided in the motor drive, then protection function is achieved, but size, weight, cost and complexity increase
Solution Approach 1:
The patent merges the lightning strike protection function with the existing PCB end winding structure. By integrating TVS diodes and other protection components directly onto the PCB that already serves as the end winding connection, the protection function is combined with the existing structural element, avoiding additional size, weight, and complexity in the motor drive assembly.
Solution Approach 2:
The PCB is designed to serve multiple functions: it acts as the end winding connection structure, provides electrical isolation between phases, and simultaneously houses the lightning strike protection components. This multi-functionality eliminates the need for separate protection devices and reduces overall system complexity.
4Reliability
If end windings are connected by passing leads over other end windings, then electrical connection is achieved, but bulk is added and additional insulation is required
Solution Approach 1:
The patent replaces the mechanical routing of leads over other end windings with an electrical connection system on the PCB. Instead of physically routing leads through space, the connections are made through PCB copper traces and pads, eliminating the need for additional bulk and reducing the space required for lead routing and insulation.
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 solution reduces the size, weight, and complexity of motor and motor drive assemblies by integrating lightning strike protection into the end winding PCB, maintaining low resistance connections and improving high-frequency operations while maintaining the benefits of multi-strand wire constructions.
Implementation Method 1
The PCB includes transient voltage suppression components to provide a lightning strike protection (LSP) function to the motor
Implementation Method 2
it is necessary to have complete electrical and magnetic isolation between different windings or winding channels so as not to propagate electrical faults through the system
Implementation Method 3
using multi-stranded wire (e.g. Litz wires) for the windings, so as to reduce eddy current effects, proximity effects and circulating currents within the conductor bundle, and the associated losses
Data Source
Figure 1~3
AI summary
An electric motor comprising: a stator; a rotor; and a printed circuit board, pcb, mounted to an end of the motor, the motor end windings being provided as connections on the pcb; the motor further comprising transient voltage suppression, TVS, components (40) on the pcb.