Motor d-q Current Control for Vehicle Drive Heating Under Load
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Solution Overview
Problem
The heating effect of electric drive systems in vehicles is uncontrollable, particularly in low ambient temperatures, and is mainly limited to stationary scenarios, restricting its application range.
Innovation Solution
A control method for electric drive systems that dynamically adjusts heat generation by determining target torque and current values based on vehicle conditions, using a quadrature-direct axis current combination to optimize heating in both traveling and stationary states without altering hardware topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electric drive system operates in a stationary state to provide heating, then the heating effect is improved, but the application scope is limited and cannot meet traveling state requirements
Solution Approach 1:
The patent implements dynamic control of the motor operating point by adjusting direct-axis and quadrature-axis current values based on real-time vehicle state (stationary or traveling). This allows the system to adaptively optimize heat generation for different operating conditions, transforming the system from a static heating solution to a dynamic one that works effectively in both stationary and traveling states.
2Temperature
If the motor current is increased to enhance heating effect, then the heat generation amount is improved, but the vehicle torque output is reduced
Solution Approach 1:
The patent changes the operating parameters (direct-axis current Id and quadrature-axis current Iq) to move the motor operating point from the original optimal efficiency point to a new point that provides required heating. The control system calculates adjusted current values based on the desired heat generation amount, allowing flexible adjustment of the torque-heat trade-off ratio according to actual vehicle needs.
Solution Approach 2:
The system dynamically adjusts the motor operating point based on real-time requirements. When heating is needed, the operating point shifts along the torque curve to increase heat generation; when torque is prioritized, the operating point returns to the optimal efficiency position. This dynamic adjustment enables the system to flexibly balance between torque output and heat generation.
3Temperature
If the waste heat amount is increased to meet heating demands, then the heating effect is improved, but the control precision is lost
Solution Approach 1:
The patent implements closed-loop feedback control by continuously monitoring the actual heat generation amount and comparing it with the target value. Based on the deviation between actual and target heat amounts, the system adjusts the motor operating point to correct the heat generation level, thereby achieving precise control of waste heat amount and improving control precision.
4Temperature
If the motor operating point is adjusted to increase heat generation, then the heating effect is improved, but the system complexity increases
Solution Approach 1:
The motor controller utilizes its existing current control capabilities and operating point adjustment functions to generate heat, without requiring additional heating hardware or complex external control systems. The system leverages the motor's inherent electrical characteristics and control mechanisms to achieve heating, thereby avoiding increased system complexity while still providing effective heat generation.
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
Enables adjustable heat generation to meet heating demands in various vehicle conditions, enhancing occupant comfort and expanding application scenarios while maintaining normal vehicle operation at a lower cost.
Implementation Method 1
the stator windings of the motor have a certain resistance, and when current flows through the stator windings, heat is generated due to resistive heating
Data Source
AI summary
A method for controlling an electric drive system, includes: determining that the vehicle is in a traveling condition; obtaining a rotation speed value, a shaft end torque value, a present direct axis current value, and a present quadrature axis current value of the motor when receiving a vehicle heat-up demand signal; determining a target torque curve according to the shaft end torque value, and determining a target traveling heating calibration curve according to the vehicle heat-up demand signal and the rotation speed value; determining an intersection of the target torque curve and the target traveling heating calibration curve as a target traveling condition point; determining a target quadrature axis current value and a target direct axis current value according to the target traveling condition point; and controlling, according to the target direct axis current value and the target quadrature axis current value, the motor to operate.