Rotary Machine Control via Dynamic Low-Pass Filtering
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Solution Overview
Problem
Rotary electric machines in vehicles experience excessive torque fluctuations and vibrations during startup due to hyperbolic torque-rotational speed characteristics, leading to user discomfort.
Innovation Solution
A rotary electric machine control apparatus with a limit torque calculating unit and a filter processing unit that applies a low-pass filter process, adjusting the time constant based on drive permissive power and rotational speed to suppress vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper limit power generation amount is supplied as permissive power for the rotary electric machine operation, then the power source state can be effectively managed, but excessive torque fluctuations and vibrations occur during startup due to hyperbolic torque-rotational speed characteristics
Solution Approach 1:
A low-pass filter is introduced as an intermediary between the permissive power calculation and the torque command generation. The filter processes the permissive power signal to remove high-frequency components before torque calculation, thereby eliminating vibrations while preserving the power source management function. The filter acts as a mediator that smooths the relationship between power constraints and torque output.
Solution Approach 2:
The patent changes the parameter of the permissive power by applying a low-pass filter, which modifies the frequency characteristics of the power signal. This parameter transformation converts the hyperbolic torque-rotational speed relationship into a smoother curve, reducing torque fluctuations during startup while maintaining the overall power management strategy.
2Object-affected harmful factors
If a low-pass filter process is applied to the limit torque calculation, then vibrations are suppressed, but the response time of the torque control increases
Solution Approach 1:
The patent applies dynamic adjustment of the low-pass filter characteristics based on the rotational speed of the rotary electric machine. At low speeds where vibrations are problematic, the filter is applied with specific time constants. At higher speeds where response time is critical, the filter characteristics are adjusted or bypassed. This dynamic adaptation allows the system to suppress vibrations when necessary while maintaining fast response when performance is prioritized.
Data Source
AI summary
It is possible to suppress vibration of a rotary machine in a rotary machine control apparatus. A drive control system of a fuel cell vehicle having a rotary machine includes a control unit having: a drive permission power calculation module which calculates the rotary machine drive permission power according to the states of a fuel cell and an accumulator as power sources of the rotary machine: a limit torque calculation module which calculates a limit torque of the rotary machine according to the drive permission power; and a filter processing module which performs a low-pass process on the limit torque calculation. A storage device of the control unit stores a filter processing region map indicating the region where the filter process is executed by correlating the region with the drive permission power and the rpm.