MOS Heater Controller Closed-Loop Power Control via CAN Bus

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Solution Overview

Problem

Conventional relay control methods for engine heaters lack precise control strategies, leading to mechanical wear and potential faults such as contact adhesion and vehicle fires, as they cannot adjust power at any time effectively.

Innovation Solution

A control method and apparatus that integrate a main control circuit board, fault detection circuit board, and MOS array within a controller, allowing for real-time communication via a CAN bus to adjust heater power and detect initial and real-time states, enabling closed-loop control and failure protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If relay control method is used, then heater power cannot be adjusted at any time, but mechanical wear and contact faults occur

Engineering Contradiction:

Improveheater power adjustment capabilityVSAvoidcontact reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the mechanical relay system with an electronic control system using MOS tubes (field-effect transistors). The controller includes a MOS tube array that can be electronically switched on and off based on control signals from the ECU, eliminating mechanical contacts and their associated wear and reliability issues while enabling precise, continuous power adjustment of the heater.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements continuous power adjustment by changing the duty cycle parameter of the MOS tube switching. The ECU sends control commands that adjust the proportion of time the MOS tube remains on during each switching cycle, thereby continuously varying the average power delivered to the heater without mechanical contact wear.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If relay control method is used, then control strategy is insufficiently precise, but mechanical wear occurs

Engineering Contradiction:

Improvecontrol precisionVSAvoidcontact durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical relay control system with an electronic MOS tube switching system. This substitution enables precise control through electronic duty cycle modulation while completely eliminating mechanical contact wear, achieving both high measurement precision and high reliability simultaneously.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a closed-loop control system where the ECU receives feedback information and adjusts the MOS tube control commands accordingly. This feedback mechanism enables precise, adaptive control of heater power while maintaining the reliability benefits of the mechanical-contact-free electronic switching system.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If relay control method is used, then contact adhesion and fuse faults may occur, but heater power adjustment is limited

Engineering Contradiction:

Improveheater power adjustabilityVSAvoidcontact fault risks

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical relay system with an electronic MOS tube switching system, eliminating mechanical contacts that are prone to adhesion, fuse, and wear faults. The electronic switching provides reliable, maintenance-free operation while enabling continuous heater power adjustment through duty cycle control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses MOS tubes that can be rapidly switched on and off without degradation. Unlike mechanical contacts that degrade over time, the electronic MOS tubes provide long-lasting, fault-resistant switching capability that can handle frequent power adjustment cycles without accumulating wear or developing contact faults.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS11649790B1Control method and apparatus applied to controller

Publication Date: 2023.05.16 WEICHAI POWER CO LTD

AI summary

A control method and a control apparatus are provided. A main control circuit board in a controller receives an initial control command via a CAN bus from an ECU after being powered on, controls a fault detection circuit board to detect initial states of the controller and all devices connected to the controller based on the initial control command to obtain initial state information, transmits the initial state information to the ECU via the CAN bus, receives a first target control command via the CAN bus from the ECU, and controls a conduction control circuit board to turn on at least one MOS in a MOS array based on the first target control command to output a control signal to a heater connected to the controller to control the heater to operate, thereby realizing a closed-loop control on the heater and adjusting a power of the heater at any time.