Motor Driving Device Power Failure Detection
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Solution Overview
Problem
Existing motor driving devices face challenges in accurately detecting power failures and voltage sags due to varying power source voltage amplitudes, leading to either inadequate or excessive protection, and increased computational load with multiple voltage drop detection sections.
Innovation Solution
A motor driving device with a rectifier, inverter, voltage amplitude detection section, counter input determination section, and power failure detection section that accumulates a counter input value inversely proportional to power failure tolerance, allowing for accurate detection by comparing it with a threshold value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple voltage drop detection sections with different reference voltage and reference time values are provided, then power failure detection accuracy is improved, but computational load is increased
Solution Approach 1:
The patent changes the parameter representation from multiple fixed reference values to a single reference value combined with a variable counter input value that is inversely proportional to power failure tolerance. This allows the detection system to adapt to different voltage conditions without increasing computational complexity, as the counter input value dynamically adjusts based on the detected voltage amplitude.
Solution Approach 2:
The patent introduces dynamics by making the counter input value variable rather than fixed. The counter input value changes based on the detected voltage amplitude, allowing the detection threshold to adapt dynamically to different operating conditions. This eliminates the need for multiple static detection sections while maintaining detection accuracy across various power failure scenarios.
2Device complexity
If a single reference voltage value is used for power failure detection, then device complexity is reduced, but detection accuracy varies with voltage amplitude
Solution Approach 1:
The patent uses parameter changes by modifying the counter input value based on the detected voltage amplitude. When voltage amplitude changes, the counter input value is adjusted inversely proportional to the power failure tolerance, allowing a single reference voltage value to effectively cover multiple detection scenarios that would otherwise require multiple reference values.
Solution Approach 2:
The counter input value acts as an intermediary between the detected voltage amplitude and the power failure detection threshold. Instead of directly comparing voltage amplitude to multiple reference values, the system uses the counter input value as a mediator that translates voltage conditions into an appropriate detection threshold, simplifying the overall detection logic.
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 accurate power failure detection with a simple configuration, effectively managing power failure tolerance and reducing computational load while ensuring timely protection of the device and associated equipment.
Implementation Method 1
a rectifier for converting three-phase AC input power source into DC power
Implementation Method 2
at least one inverter for converting the DC power into AC power of a desired frequency
Data Source
AI summary
A motor driving device that accurately achieves power failure detection according to a power failure tolerance with a relatively simple configuration. A counter input computing unit determines, as a counter input value, a value that is inversely proportional to the power failure tolerance determined from a voltage amplitude value and supplies the counter input value to a counter. The counter accumulates the input value at predetermined intervals and outputs an output value. A comparator determines that power failure occurs if the output of the counter 42 exceeds a threshold value.