Redundant Motor Driver Control Using Adjustable Fault-State Current
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Solution Overview
Problem
Existing control devices for electric motors, particularly in steering systems, suffer from reduced power efficiency and increased costs due to the use of additional switches and resistors to prevent current flow between redundant driver units, which are necessary for maintaining operation in fault conditions.
Innovation Solution
A control device with a primary and secondary driver unit, where the secondary unit has an integrated power source with adjustable current strength, allowing it to take over in fault conditions, thereby improving efficiency and reducing computational effort by using the same components and connection lines for both units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional switches and resistors are used to prevent current flow between parallel driver units, then operational reliability is improved, but power efficiency deteriorates and device complexity increases
Solution Approach 1:
The patent applies dynamics by making the driver units switchable between active and inactive states through controlled current flow. The secondary driver unit can be dynamically activated or deactivated based on operational needs, allowing the system to adapt its configuration rather than relying on fixed passive components like resistors or switches that continuously consume power.
Solution Approach 2:
The invention changes the current strength parameter of the power source connected to the secondary driver unit. By adjusting the current to a first value (below a first limit) in normal operation and a second value (above a second limit) when activation is needed, the system achieves reliable switching between driver units without requiring additional power-consuming protective components.
2Reliability
If additional switches and resistors are used to prevent current flow between parallel driver units, then operational reliability is improved, but device complexity and costs increase
Solution Approach 1:
The power source serves multiple functions: it provides power to the secondary driver unit and simultaneously controls its activation state through current strength adjustment. This eliminates the need for separate switches and resistors, reducing device complexity while maintaining the ability to ensure reliable operation by preventing unwanted current flow between parallel driver units.
Solution Approach 2:
The secondary driver unit's power source self-regulates the current flow to control the activation state of the driver unit. By monitoring and adjusting its own current output, the power source inherently prevents unwanted current flow without requiring external protective components, thereby simplifying the overall device structure.
3Reliability
If the secondary driver unit is kept ready with full power capability, then fault state response is improved, but power consumption in normal state increases
Solution Approach 1:
The system dynamically adjusts the current strength provided to the secondary driver unit based on operational state. During normal operation, the current is reduced to a first value that maintains basic readiness without full power consumption. When a fault is detected, the current can be rapidly increased to a second value above the second limit, enabling the secondary driver unit to take over immediately while minimizing power consumption during normal operation.
Data Source
AI summary
A control device for operating an electric motor, in particular a steering system, includes a power electronics, a primary driver unit provided for actuating the power electronics in a normal operating state, and a secondary driver unit connected in parallel to the primary driver unit and provided for actuating the power electronics in at least one fault operating state in which a malfunction and/or failure of the primary driver unit occurs. The secondary driver unit comprises a power source having an adjustable current strength for controlling a switching state of at least one circuit breaker of the power electronics. An absolute value of the power source in the normal operating state is set to a first value which is below a first limit value, and in the at least one fault operating state it is set to a second value which is above a second limit value.