Inverter Voltage-to-Frequency Control with Multi-Gain Segmentation
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Solution Overview
Problem
Existing inverter apparatuses using voltage-to-frequency control methods lack high-resolution voltage variation, leading to inefficient torque control in induction motors due to the inability to accurately adjust output frequency without corresponding voltage changes.
Innovation Solution
The inverter apparatus comprises multiple circuits and a micro-controller unit that processes analog input voltages through clipping and gain units, converting them into digital values for selecting the largest output to generate a corresponding output frequency, thereby enhancing voltage resolution and control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single gain unit is used to convert analog input voltage to output voltage, then the circuit structure is simple, but the voltage resolution is low and cannot provide high-resolution voltage variation for accurate control
Solution Approach 1:
The patent divides the single gain unit into multiple gain units (first gain unit, second gain unit, third gain unit) with different gain values. Each gain unit processes the analog input voltage to produce a different analog output voltage, thereby segmenting the voltage conversion function to achieve higher resolution without excessive complexity.
Solution Approach 2:
The patent introduces a new dimension by adding multiple gain units operating in parallel rather than a single sequential gain unit. This dimensional expansion allows the system to process the same input signal through multiple transformation paths, increasing the resolution of voltage variation detection.
2Adaptability or versatility
If the analog input voltage range is large, then the control range is wide, but the voltage gain becomes small reducing control precision in small-signal portions
Solution Approach 1:
The patent applies different gain values to different gain units, creating local quality variations in the signal processing path. The first gain unit, second gain unit, and third gain unit each have distinct gain characteristics optimized for specific signal ranges, allowing high precision in small-signal portions while maintaining wide control range through the combination of all units.
Solution Approach 2:
The system dynamically selects among multiple gain units based on the input signal characteristics. By having multiple gain units with different gain values available and selecting the appropriate one based on signal amplitude, the system adapts its gain characteristics to maintain precision across the full control range.
Data Source
AI summary
An inverter apparatus has an adaptable high-resolution voltage-to-frequency (V/f) control. The inverter apparatus receives an analog input signal and includes a first circuit, a second circuit, a third circuit, and a micro-controller unit. The first circuit processes a small-signal portion of the analog input signal with a larger voltage gain. The second and the third circuit both processes large-signal portions of the analog input signal with smaller voltage gains respectively. The three processed analog input signals of the first, the second, and the third circuits are converted into three digital output values respectively. The largest digital output value is selected by the micro-controller unit and supplied to a frequency operation unit for generating a corresponding output frequency.