Synchronous Motor Vector Control for Regenerative Current Limiting
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Solution Overview
Problem
Existing methods for limiting regenerative current in synchronous type electric motors, such as power steering motors, either require bulky and expensive passive elements or modify the motor torque, leading to deviations in the driver's experience.
Innovation Solution
A method for controlling a synchronous type electric motor using vector control, where the AC supply current is determined through a series of steps to maintain motor torque at the setpoint while ensuring the DC supply current remains above a global regeneration threshold, without additional components, by adjusting direct and quadrature axis currents based on static and dynamic thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If passive elements such as resistive elements are used to reduce regenerative current, then regenerative current is limited, but the device becomes bulky and expensive
Solution Approach 1:
The patent replaces passive resistive elements with an active control system that uses vector control methodology. The microcontroller adjusts the quadrature axis current (Iq) and direct axis current (Id) to regulate motor torque, thereby controlling regenerative current through software-based torque management rather than physical resistive components.
Solution Approach 2:
The patent changes the operational parameters of the motor by dynamically adjusting the quadrature axis current (Iq) and direct axis current (Id) through vector control. By modifying these current components, the system regulates the motor's torque output and consequently controls the regenerative current flow without requiring additional hardware.
2Object-generated harmful factors
If DC supply current is limited with priority over setpoint torque, then regenerative current is limited, but motor torque deviates from setpoint torque
Solution Approach 1:
The patent employs dynamic torque regulation through vector control, where the quadrature axis current (Iq) and direct axis current (Id) are continuously adjusted based on operating conditions. This dynamic control allows the system to maintain motor torque at the setpoint value while simultaneously regulating regenerative current, adapting in real-time to different operational scenarios.
Solution Approach 2:
The patent implements a feedback control mechanism where the microcontroller monitors the motor's operational state and adjusts the AC supply current components accordingly. By continuously comparing actual torque with setpoint torque and regulating the quadrature and direct axis currents, the system ensures torque consistency while limiting regenerative current flow.
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
Effectively limits regenerative current without additional components, maintaining motor torque consistency and avoiding torque deviations, thus enhancing the driving experience.
Implementation Method 1
the inverter being driven by at least one microcontroller using a vector control method
Implementation Method 2
synchronous type rotary electric motor, having at least three phases
Data Source
AI summary
A method for controlling an electric motor (12) comprising at least:one first determination step (E1) in which an intermediate value of a direct axis current (Idstat) and an intermediate value of a quadrature axis current (Iqstat) of the AC supply current of the motor (12) are determined,one second determination step (E2) in which a target value of the direct axis current (Idcible) and a target value of the quadrature axis current (Iqcible) are determined,one driving step (EP) in which the at least one inverter is driven by the microcontroller (20) based on the target value of the direct axis current (Idcible) and the target value of the quadrature axis current (Iqcible).