EV Inverter Torque Control via Variable Switching Frequency
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Solution Overview
Problem
Current electric vehicle motor control systems do not adequately explore the relationship between motor control systems and torque output, limiting the acceleration performance of electric vehicles.
Innovation Solution
A system and method that includes a torque capability controller and a PWM inverter, where the switching frequency is adjusted based on a selected mode to increase torque output, reducing switching loss and allowing higher current to improve acceleration performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If switching frequency is reduced to allow higher current and increase torque output, then acceleration performance is improved, but switching loss increases
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The control system dynamically modifies the switching frequency of the inverter based on operating conditions, allowing it to be reduced during high-torque需求的acceleration phases to enable higher current flow and torque output, while potentially being increased during normal operation to minimize switching losses.
Solution Approach 2:
The patent changes the parameter of switching frequency to resolve the contradiction. By modifying the switching frequency parameter from a fixed value to a variable parameter that can be adjusted based on torque requirements, the system can optimize between torque output and switching loss at different operating points.
2Force
If higher current is supplied to increase torque output, then acceleration performance is improved, but heat generation increases
Solution Approach 1:
The system dynamically adjusts switching frequency in response to thermal conditions and torque demands. When high torque is needed, the switching frequency is reduced to allow higher current flow, but the system monitors thermal conditions and adjusts accordingly to prevent excessive heat generation that would damage components.
Solution Approach 2:
The control system employs feedback mechanisms to monitor operating conditions including current, temperature, and torque output. This feedback allows the system to adjust the switching frequency in real-time, reducing it when high torque is needed and current is safe, and increasing it or limiting current when thermal conditions approach dangerous levels.
3Force
If switching frequency is reduced to enable higher torque, then acceleration performance is improved, but control precision may deteriorate
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The control system dynamically modifies the switching frequency of the inverter based on operating conditions, allowing it to be reduced during high-torque需求的acceleration phases to enable higher current flow and torque output, while potentially being increased during normal operation to minimize switching losses.
Solution Approach 2:
The patent changes the parameter of switching frequency to resolve the contradiction. By modifying the switching frequency parameter from a fixed value to a variable parameter that can be adjusted based on torque requirements, the system can optimize between torque output and switching loss at different operating points.
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 system enhances torque output and acceleration performance by reducing switching loss and increasing current within heat and power limits, improving 0-60 mph times by 0.5-1.2 seconds compared to normal mode.
Implementation Method 1
an inverter configured to drive the electric motor. The inverter may include at least one power electronic device
Implementation Method 2
The torque capability controller may also be configured to apply a switching frequency to the at least one power electronic device. The switching frequency may have a lower value when the received information indicates the selection of the second mode than when the received information indicates the selection of the first mode
Data Source
AI summary
Systems and methods are disclosed for improving acceleration performance of an electric vehicle that includes an electric motor for propulsion. An exemplary system may include an inverter configured to drive the electric motor. The inverter may include at least one power electronic device. The system may also include a torque capability controller. The torque capability controller may be configured to receive information indicative of a selection between a first mode and a second mode. The second mode may correspond to a higher torque to be output by the electric motor than the first mode. The torque capability controller may also be configured to apply a switching frequency to the at least one power electronic device. The switching frequency may have a lower value when the received information indicates the selection of the second mode than when the received information indicates the selection of the first mode.