Motor Control Device Segmented Driver Stage Safety Management
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Solution Overview
Problem
Conventional motor control devices for motor units, particularly in safety-critical applications like vehicles, face challenges in reliably detecting and responding to malfunctions, which can lead to component failure and unsafe conditions due to inadequate safety levels and power handling capabilities.
Innovation Solution
A motor control device with a control unit, safety stage, and driver stage featuring three separate electronic circuits for the power bridge circuit, allowing for synchronized operation and selection of safety states to ensure safe operation even in malfunction scenarios, meeting safety requirements up to ASIL C and D levels, and extending the power range of motor units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If three separate electronic circuits are used to control the power bridge circuit, then the power range is extended and can be tripled, but the device complexity increases and safety management becomes more challenging
Solution Approach 1:
The driver stage is segmented into three separate electronic circuits (first, second, and third electronic circuits) that independently control different portions of the power bridge circuit. This segmentation enables the system to handle higher power levels by distributing the control across multiple circuits, with each circuit managing a specific phase or portion of the overall power conversion process.
Solution Approach 2:
The safety stage is designed as a universal control unit that manages multiple functions simultaneously: it monitors all three electronic circuits, detects malfunctions in any of them, selects appropriate safety states, and coordinates the response across all circuits. This multi-functional safety stage simplifies the overall system architecture by providing centralized control for what would otherwise be three separate control systems.
2Power
If multiple electronic circuits are used to control the power bridge circuit, then the power handling capability increases, but the reliability decreases due to increased risk of malfunction and shorter circuit failures
Solution Approach 1:
The safety stage continuously monitors the operational status of all three electronic circuits through feedback signals. When a malfunction is detected in any circuit, the safety stage receives feedback about the specific failure condition and automatically responds by selecting an appropriate safety state. This closed-loop feedback mechanism ensures that the system can detect and respond to failures in real-time, maintaining reliability despite the presence of multiple circuits.
Solution Approach 2:
The system incorporates predefined safety states that are prepared in advance to handle various malfunction scenarios. Before a failure occurs, the safety stage is configured with multiple safety states (such as safe operating states and safe failure states) that can be immediately activated upon detecting a malfunction. This prior preparation ensures that when a circuit fails, the system can quickly transition to a safe state without compromising reliability.
3Device complexity
If conventional single electronic circuit control is used, then the device complexity is lower, but the power range is limited and safety response capability is insufficient
Solution Approach 1:
Instead of using a single electronic circuit to control the entire power bridge circuit, the system segments the control function across three separate electronic circuits. Each circuit is responsible for controlling a specific phase or portion of the power bridge, enabling the system to handle higher power levels that would be impossible for a single circuit to manage alone.
Solution Approach 2:
The safety stage acts as an intermediary between the control unit and the three electronic circuits of the driver stage. It receives control signals from the control unit and distributes them to the appropriate electronic circuits, while also monitoring their operational status. This intermediary structure enables coordinated control of multiple circuits without requiring complex direct communication between all components.
4Reliability
If three separate electronic circuits are implemented with synchronized safety state management, then safety standards up to ASIL C and D levels are met, but the ease of operation decreases due to coordination requirements
Solution Approach 1:
The safety stage is designed as a universal control unit that consolidates multiple safety management functions into a single device. It simultaneously monitors all three electronic circuits, detects malfunctions in any of them, selects appropriate safety states, and coordinates the response across all circuits. This multi-functional design meets stringent safety standards (ASIL C and D) while maintaining ease of operation by centralizing control rather than requiring separate safety management for each circuit.
Data Source
Figure 1~2A
Figure 2B
Figure 3
AI summary
The invention relates to a motor control device (3) for a motor unit (2) comprising a control unit (4), a safety stage (S) for setting a safety state (STATE1, STATE2) of the motor unit (2), a driver stage (5), and a power bridge circuit (6), wherein the driver stage (5) comprises three separate electronic circuits (IC1 to IC3) for controlling the power bridge circuit (6), and the safety stage (S) is configured, in the event of a detected malfunction of the power bridge circuit (6), to select and/or activate a safety state (STATE1, STATE2) associated with the malfunction and to synchronize the three electronic circuits (IC1 to IC3) depending on the selected safety state (STATE1, STATE2). The invention further relates to a method