Rotary Machine Control Dead-Time Compensation
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Solution Overview
Problem
Existing rotary electric machine control methods face challenges in accurately detecting the magnetic pole position, especially at low speeds and low torque conditions, due to voltage errors caused by dead time, which affects detection accuracy and operation efficiency.
Innovation Solution
A sensorless magnetic pole position detection technique that performs dead-time compensation by adjusting the start and end points of control pulses for inverter switching elements, ensuring the armature current magnitude is maintained at or above a lower-limit current, thereby reducing voltage errors and improving detection accuracy while minimizing efficiency impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dead-time compensation is performed by adjusting control pulse timing, then voltage error due to dead time is reduced and magnetic pole position detection accuracy is improved, but operation efficiency is lowered
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the armature current magnitude based on operating conditions. When dead-time compensation is active, the system modifies current parameters to compensate for efficiency losses, ensuring current magnitude remains above a lower limit while optimizing the balance between detection accuracy and operational efficiency
2Measurement precision
If armature current magnitude is increased to maintain detection accuracy, then magnetic pole position detection accuracy is improved, but operation efficiency is lowered
Solution Approach 1:
The patent implements dynamics by making the armature current magnitude adjustable and adaptive rather than fixed. The control device dynamically modifies current magnitude based on detection requirements and operational conditions, allowing the system to maintain sufficient current for accurate magnetic pole position detection while minimizing energy consumption by keeping current above a lower limit rather than continuously high
3Manufacturing precision
If dead-time compensation is performed, then voltage error is reduced, but the proportion of time when phase currents are near zero increases, reducing detection accuracy
Solution Approach 1:
The patent applies feedback by using the detected magnetic pole position information to optimize control pulse timing and adjust armature current magnitude. The feedback loop ensures that dead-time compensation is performed effectively while maintaining sufficient current magnitude to prevent prolonged zero-current periods, thereby preserving detection accuracy
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
This approach allows for accurate electrical derivation of the magnetic pole position, reducing voltage errors and maintaining operation efficiency by ensuring sufficient armature current magnitude, even at low torque conditions.
Implementation Method 1
an inverter that performs power conversion between AC power and DC power
Implementation Method 2
a rotor in which a permanent magnet is disposed
Implementation Method 3
a magnetic pole position is detected utilizing an induced electromotive force produced by rotation of the rotor
Data Source
AI summary
The magnetic pole position of a rotary electric machine is electrically derived accurately by reducing a voltage error due to a dead time while suppressing the influence on the operation efficiency of the rotary electric machine. A control device performs dead-time compensation, and performs current feedback control in a d-q-axis vector coordinate system using a magnetic pole position computed on the basis of an induced voltage produced by rotation of a rotor or on the basis of a response component to a high-frequency observation signal applied to the rotary electric machine. In the case where the rotary electric machine is controlled by deciding current commands Id*, Iq* in the d-q-axis vector coordinate system, the rotary electric machine control device controls the rotary electric machine such that the magnitude of an armature current Ia becomes equal to or more than a lower-limit current Ia_min prescribed in advance.