Fuel Cell Air Compressor Speed Control via Torque History Estimation

Solution Overview

Problem

Conventional fuel cell systems experience overshoot of air compressor rotational speed due to delays in measured value transmission among ECUs, leading to inaccuracies in rotational speed control.

Innovation Solution

A fuel cell system with a controller that estimates the current rotational speed of the air compressor based on a history of torque command values, reducing the influence of delays by using estimated rotational speed to calculate the torque command value, and incorporating filtering and smoothing processing to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the measured rotational speed value is transmitted among multiple ECUs, then the rotational speed information can be shared and used for control, but the reception delay causes the measured value to differ from the actual current rotational speed, resulting in overshoot

Engineering Contradiction:

Improverotational speed information accuracyVSAvoidmeasurement value transmission delay

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The system performs preliminary estimation of the current rotational speed by combining the measured value with the history of torque command values before using it for control calculations. This preliminary action compensates for the time delay inherent in measurement value transmission among ECUs, ensuring that the control system operates with more accurate and timely rotational speed information.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller acts as an intermediary that receives the measured rotational speed value from one ECU, estimates the current rotational speed by incorporating torque command history, and then uses this estimated value for control calculations. This intermediary processing resolves the timing mismatch between measurement and control usage across multiple ECUs.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If filtering is applied to the measured rotational speed value, then noise is reduced, but the delay in obtaining the filtered value increases, potentially causing overshoot

Engineering Contradiction:

Improverotational speed measurement accuracyVSAvoidfiltering processing delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary estimation of the current rotational speed by combining the measured value with the history of torque command values before using it for control calculations. This preliminary action compensates for the time delay inherent in measurement value transmission among ECUs, ensuring that the control system operates with more accurate and timely rotational speed information.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the history of torque command values to estimate the current rotational speed. By incorporating this feedback information, the system can compensate for delays introduced by filtering operations, maintaining both measurement precision and timely response for control purposes.

Inventive Principle:

Principle #23Feedback

3Productivity

If the torque command value is calculated using the current rotational speed, then the control response is immediate, but the delay in measured value reception causes inaccuracy in the calculated torque

Engineering Contradiction:

Improvecontrol response speedVSAvoidrotational speed measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary estimation of the current rotational speed by combining the measured value with the history of torque command values before using it for control calculations. This preliminary action compensates for the time delay inherent in measurement value transmission among ECUs, ensuring that the control system operates with more accurate and timely rotational speed information.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller acts as an intermediary that receives the measured rotational speed value from one ECU, estimates the current rotational speed by incorporating torque command history, and then uses this estimated value for control calculations. This intermediary processing resolves the timing mismatch between measurement and control usage across multiple ECUs.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9970447B2Fuel cell system and method for controlling rotational speed of air compressor

Publication Date: 2018.05.15 TOYOTA JIDOSHA KK

AI summary

A fuel cell system includes an air compressor that supplies oxidant gas to a fuel cell installed in a fuel cell vehicle, a measured rotational speed acquirer that acquires a measured value of rotational speed of the air compressor, and a controller that calculates a rotational speed command value of the air compressor based on required generated power of the fuel cell, calculates a torque command value of the air compressor based on the calculated rotational speed command value and current rotational speed of the air compressor, and controls rotational speed of the air compressor based on the calculated torque command value. The controller estimates the current rotational speed of the air compressor baaed on the measured value of the rotational speed acquired by the measured rotational speed acquirer and a history of the calculated torque command value, and calculates the torque command value by using the estimated rotational speed.