Motor Winding Inductance for Auxiliary Power Conversion
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Solution Overview
Problem
Existing motor drive inverters face excessive power dissipation due to the use of high voltage linear regulators for system microcontrollers and other circuitry, and auxiliary power supplies like buck converters or flyback converters incur additional costs and board space.
Innovation Solution
Utilizing the inherent inductance of a motor winding to store and convert energy for an auxiliary power supply, eliminating the need for a dedicated inductive energy transfer element and reducing power dissipation by reusing existing inverter switches as a switched-mode power converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage linear regulators are used to power system microcontrollers and other circuitry, then the motor drive inverter can power itself indefinitely, but excessive power dissipation occurs from the linear regulator
Solution Approach 1:
The patent replaces the linear regulator (electrical component) with a switched-mode power converter that uses the motor winding inductance as its energy storage element. This substitution eliminates the excessive power dissipation associated with linear regulators while maintaining self-sustaining operation of the motor drive inverter.
Solution Approach 2:
The motor winding itself serves dual purposes: it functions as both the motor actuator and the energy storage inductor for the auxiliary power supply. This self-service approach eliminates the need for separate inductive energy transfer elements and reduces overall system power consumption.
2Loss of energy
If auxiliary switching power supplies (buck or flyback converters) are used to efficiently derive power for motor drive inverters from the high voltage bus, then power efficiency is improved, but additional cost and board space are required
Solution Approach 1:
The motor winding is made multi-functional by using it both as the motor actuator and as the inductive energy transfer element for the auxiliary power supply. This eliminates the need for dedicated inductive elements and reduces device complexity while maintaining efficient power conversion.
Solution Approach 2:
The patent merges the motor winding with the auxiliary power supply inductor function. By combining these two functions into a single component (the motor winding itself), the system eliminates additional circuitry and reduces board space requirements while maintaining switching-mode power conversion efficiency.
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 reduces power dissipation and eliminates the need for additional circuitry, providing efficient power to motor driver ICs and system microcontrollers while minimizing motor movement during stationary or low-power operation.
Implementation Method 1
A winding of a motor having a winding inductance is coupled to a half-bridge motor driver circuit
Implementation Method 2
In a first state, the switching circuit is configured to take current from a high voltage power source that powers the motor and to store energy in the winding as current in the inductance of the winding
Data Source
AI summary
A motor driver couples to an auxiliary power supply and to a motor having a winding. The motor driver comprises a first switch and a second switch. The first switch is coupled to the winding at a winding node. The second switch is coupled to the first switch and the auxiliary power supply at an auxiliary node. The auxiliary node corresponds to an output terminal of the first switch and an input terminal of the second switch. The motor driver further comprises control circuitry to place the first switch and the second switch into a first switching configuration in which energy is stored in an inductance of the winding, and a second switching configuration in which the stored energy is delivered to the auxiliary power supply via current through the winding node and the auxiliary node.