Safety Function Unit Segmentation for Independent Certification
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Solution Overview
Problem
The integration of power conversion devices and safety modules makes it difficult to efficiently test and certify the safety module independently, leading to increased costs and product prices, as changes in safety function parts require re-certification of the entire system.
Innovation Solution
A safety function unit is introduced within the power conversion device, which includes an input terminal, output terminal, drive signal path, and interruption circuit, allowing the safety function to be tested and certified independently of other components, with the option to connect directly or through a safety function circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power conversion device and safety module are integrated as a single system, then the safety function can be implemented, but it becomes difficult to test and certify the safety module independently, requiring re-certification of the entire system for any changes
Solution Approach 1:
The patent divides the integrated system into separate functional modules: the power conversion device and the safety function unit are physically and functionally separated. The safety function unit includes its own control substrate with interruption circuit, while the power conversion device has its own control substrate. This segmentation allows the safety module to be tested and certified independently according to IEC 61508 standards without requiring certification of the entire integrated system, resolving the contradiction between maintaining safety reliability and reducing testing complexity.
2Reliability
If the safety module is integrated with the power conversion device, then the safety function is achieved, but the parts cost and development cost increase, leading to higher product prices
Solution Approach 1:
By segmenting the safety function into a separate testable unit, the patent enables independent certification of the safety module. This reduces development costs because the safety module can be developed, tested, and certified once and then reused across multiple power conversion device configurations. It also reduces parts costs by eliminating the need for additional safety-related components in each integrated system, as the separated safety function unit can be optimally designed and manufactured as a standardized component.
Data Source
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AI summary
The present invention provides a configuration capable of efficiently testing only the part of the safety module of a power conversion device. The power conversion device incudes: a control unit 102 that outputs a drive signal to drive equipment to be driven; a drive unit 101 that drives the equipment to be driven based on the drive signal; a terminal unit 103 that receives a signal from an upper control device and transits to the control unit 102; and a safety function unit 104 that interferes with the drive signal transmitted from the control unit 102 to the drive unit 101. The safety function unit 104 includes: an input terminal 1006 that inputs the drive signal from the control unit 102; an output terminal 1005 that outputs the drive signal to the drive unit 101; a drive signal path connecting the input terminal 1006 with the output terminal 1005; a control terminal that receives an interruption signal from the upper control device to instruct to stop the equipment to be driven; and an interruption circuit 1001 that interferes with the drive signal in the drive signal path based on the interruption signal.