Signal Conversion Device Phase Detection for Motor Drive Control
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Solution Overview
Problem
Existing motor drive systems face challenges in accurately controlling control targets due to varying current values based on the type, power consumption, and operating state of the targets, making it difficult to set appropriate reference values for current detection and achieve high accuracy in ON/OFF control.
Innovation Solution
A signal conversion device with a first signal input terminal for an AC signal and a second signal input terminal for an in-phase and opposite-phase AC signal, where the detector determines whether the second AC signal is in-phase or opposite-phase using the first AC signal, enabling simpler control of the motor drive system by switching between these phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current detection is used for ON/OFF control of multiple control targets, then control can be achieved, but measurement precision deteriorates due to varying current values from different control target types, power consumptions, and operating states
Solution Approach 1:
The invention changes the detection parameter from current magnitude to current phase relationship. By detecting whether the current flowing to a control target is in-phase or opposite-phase with a reference AC signal, the system achieves accurate control state detection regardless of the absolute current value, which varies with different control target characteristics.
2Ease of operation
If a fixed reference value (threshold) is set for current detection, then detection can be performed, but reliability deteriorates because the threshold cannot be appropriately set for control targets with various current values
Solution Approach 1:
The invention replaces the fixed threshold parameter with a phase-based detection parameter. Instead of comparing current magnitude against a fixed threshold, the system determines the phase relationship between the detected current and reference AC signal, which provides reliable control state identification across varying current conditions without requiring threshold adjustment.
Solution Approach 2:
The system uses the detected phase relationship as feedback to determine the control target's operating state. By continuously monitoring whether the current is in-phase or opposite-phase with the reference signal, the system can reliably identify control states and provide appropriate control responses regardless of current magnitude variations.
Data Source
AI summary
A signal conversion device includes a first signal input terminal, a second signal input terminal, and a detector. A first AC signal is supplied to the first signal input terminal from a signal source. The second signal input terminal is supplied with an in-phase signal that is in phase with the first AC signal and an opposite-phase signal that is opposite in phase with the first AC signal. The second signal input terminal is supplied with a second AC signal whose phase has been switched by a switchover between the in-phase signal and the opposite-phase signal from the signal source. The detector detects, using the supplied first AC signal, whether the supplied second AC signal is the in-phase signal or the opposite-phase signal.