Asynchronous Motor Starting Torque via Inverter Parameter Tuning
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Solution Overview
Problem
Asynchronous motors in electric vehicles face challenges in achieving high starting torque without using a torque converter, which is problematic due to size, weight, and cost considerations, and existing solutions either require complex coupling arrangements or result in high power consumption.
Innovation Solution
A program-controlled, parametrizable inverter is configured to operate outside its factory specifications by setting parameters such as nominal output, frequency, and voltage to higher or lower values than recommended, allowing for increased excitation voltage and torque without the need for a torque converter, using a more powerful inverter and optimizing settings for the specific application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If simple coupling is used to start the motor, then high starting torque is achieved, but high power consumption occurs
Solution Approach 1:
The patent applies parameter changes by modifying the inverter's operational parameters (nominal output, frequency, voltage) to deviate from factory specifications. By setting the nominal output to 70-90% of actual value, frequency to 70-95% of actual value, and voltage to 105-120% of actual value, the system achieves higher excitation voltage and starting torque while reducing power consumption during motor startup
2Force
If multiple batteries are connected in parallel to supply high starting power, then high starting torque is achieved, but system size increases
Solution Approach 1:
The patent resolves this contradiction by changing the inverter's parameters to enable it to deliver higher power output than its nominal rating during startup. By configuring the inverter with adjusted parameters (lower nominal output setting, modified frequency and voltage), the system achieves high starting torque without requiring multiple batteries in parallel, thereby maintaining a compact system size
3Force
If a more powerful inverter is used to increase excitation voltage, then high starting torque is achieved, but cost and device complexity increase
Solution Approach 1:
The patent applies parameter changes to the inverter's configuration parameters rather than hardware upgrades. By adjusting software parameters (nominal output to 70-90%, frequency to 70-95%, voltage to 105-120% of actual values), the system achieves higher excitation voltage and starting torque using the existing inverter hardware, avoiding the need for a more powerful and complex inverter system
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 method enables high starting torque with reduced power consumption, minimizing battery size and weight, and allows for efficient energy recovery during braking, maintaining vehicle stability and performance without overheating the motor.
Implementation Method 1
the inverter transforms the output of the DC power supply into AC (alternating-current) voltage
Implementation Method 2
an asynchronous motor driven by an inverter
Data Source
AI summary
The invention relates to a method for generating high starting torque in an asynchronous motor at a low power consumption, using a program-controlled, parametrizable inverter for industrial use. The invention involves choosing the inverter in such a way as to increase its power output by 20-40% compared to the motor's nominal value, as well as by deviating from the manufacturer's recommendations while setting a number of the inverter's operational parameters, namely, by setting the nominal output of the motor to a value between 70% and 90% of the actual nominal output, by setting the nominal frequency of the motor to a value between 70% and 95% of the actual nominal frequency, and/or by setting the nominal voltage of the motor to a value between 105% and 120% of the actual nominal voltage.