Power Electronics Circuit Optocoupler Testing

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Solution Overview

Problem

Existing power electronic circuits for electric machines lack a reliable method to check the functionality of their drive electronics during current operation without disrupting normal functioning.

Innovation Solution

A power electronic circuit with a control device that uses a pulse pattern to alternately open and close semiconductor switches, employing an optocoupler and two semiconductor switches to enable functionality testing without affecting ongoing operations, utilizing a second semiconductor switch to verify its operation by evaluating electrical signals during normal operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If functionality testing is performed during current operation, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvefunctionality testing capabilityVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The second semiconductor switch serves dual purposes: it functions as a normal switching element during power conversion operation and as a test element for verifying optocoupler functionality. By integrating testing capability into an existing operational component, the patent enables reliability verification without adding separate dedicated test hardware, thus improving reliability while minimizing complexity increase.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The control device alternates between normal power conversion mode and test mode by periodically switching the second semiconductor switch. During test intervals, the second switch is opened to verify optocoupler functionality, while during normal operation intervals, it closes to perform power conversion. This periodic alternation enables continuous reliability testing without requiring permanent disruption of normal operations.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the second semiconductor switch is opened for testing, then functionality verification is improved, but power conversion performance deteriorates

Engineering Contradiction:
Improveswitch functionality verificationVSAvoidpower conversion efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control device implements periodic alternation between normal power conversion operation and test operation. During brief test intervals, the second semiconductor switch is opened to verify optocoupler functionality. Between these intervals, the switch returns to its normal closed state for power conversion. This periodic approach minimizes the time power conversion is disrupted while still enabling regular functionality verification.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The testing function is implemented using a portion of the existing semiconductor switch infrastructure rather than requiring complete system shutdown or extensive modifications. By utilizing the second semiconductor switch's existing circuit path for testing purposes during brief intervals, the patent achieves functionality verification with minimal impact on overall power conversion productivity.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If quick shutdown capability is implemented, then safety is improved, but response time may increase

Engineering Contradiction:
Improvesafety shutdown capabilityVSAvoidshutdown response time
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The second semiconductor switch is pre-configured in the circuit topology specifically to enable rapid shutdown functionality. During normal operation, it remains closed and ready. When shutdown is required, the control device simply opens this pre-positioned switch, which immediately interrupts the power conversion current path. This preliminary positioning of the switch in the circuit allows safety shutdown to be achieved without complex additional mechanisms or delayed response.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the reliable testing of power semiconductor switches within the power electronic circuit during ongoing operation without disturbing the machine's functionality, ensuring the second semiconductor switch opens correctly and allowing for quick shutdown or inverter blocking as needed.

Implementation Method 1

the drive electronics comprises the optocoupler, which in turn has the light transmitter as an input stage the light transmitter and as the output stage the light receiver

Methodology Applied
Scientific EffectOptocoupling: Light Emitting Diode

Implementation Method 2

The light transmitter includes e.g. a light-emitting diode and is configured to produce light when an electric current flows through the light transmitter

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 3

The light transmitter and the light receivers are optically coupled so that the light receiver receives the light generated by the light transmit and then a corresponding electrical signal

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Data Source

PatentEP2741407B1Power electronics circuit, electric machine and method for monitoring the functionality of a power electronics circuit
Publication Date: 2021.03.10 KUKA DEUT GMBH
  • EP2741407B1 patent drawingFigure 1
  • EP2741407B1 patent drawingFigure 2
  • EP2741407B1 patent drawingFigure 3

AI summary

The electronic power circuit has second semiconductor switch connected in series to parallel circuit consisting of first semiconductor switch and light emitter. The first switch is provided to be opened and closed alternately in accordance with a pulse pattern, so that an electrical current flows through light emitter in correspondence with pulse pattern and the light emitter emits light in correspondence with the pulse pattern. The emitted light is received by light receiver to generate a corresponding control signal for power semiconductor switch. Independent claims are included for the following: (1) electric machine; and (2) method for testing the electronic power circuit.