HFI Compensation Pulse for Salient Pole Motor Disturbance Elimination
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Solution Overview
Problem
High frequency injection transitions in salient pole electric machines cause temporary disturbances, leading to inaccuracies in motor angle and angular velocity estimation due to delays in drive current stabilization during ON to OFF or OFF to ON transitions.
Innovation Solution
A processor-based system determines compensation pulse voltages for a High Frequency Injection (HFI) compensation pulse, which is injected into the current regulator voltage output signal, settling the HFI current to a steady state almost instantaneously, thereby mitigating transition disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If HFI transition is directed for motor control, then position estimation accuracy is improved, but temporary disturbances occur during transition causing current stabilization delays
Solution Approach 1:
The compensation pulse is generated and injected in advance during the PWM cycle following the HFI transition, before the current stabilization delay completes. This preliminary action prevents the disturbance from affecting position estimation accuracy by proactively counteracting the expected current instability.
Solution Approach 2:
The compensation pulse applies an opposing voltage action to counteract the temporary disturbance caused by HFI transition. By injecting this compensating voltage during the transition PWM cycle, the system preemptively neutralizes the harmful current stabilization delay before it degrades measurement precision.
2Ease of operation
If HFI voltage is injected into current regulator, then drive current control is achieved, but transition disturbances cause delays in current stabilization
Solution Approach 1:
The compensation pulse is applied periodically during the PWM cycle following HFI transition, creating a structured periodic control action. This periodic injection of compensating voltage accelerates current stabilization by providing rhythmic corrective forces during the transition period, reducing the overall stabilization time.
Solution Approach 2:
The compensation pulse is injected in the PWM cycle immediately following the HFI transition, acting preliminarily to prevent prolonged current stabilization delays. This timely intervention reduces the loss of time by addressing the stabilization issue before it extends into subsequent control cycles.
3Speed
If compensation pulse is injected during transition PWM cycle, then HFI current settles to steady state rapidly, but additional control complexity is introduced
Solution Approach 1:
The compensation pulse generation utilizes the existing HFI transition detection mechanism and current regulator infrastructure. By leveraging the already-present transition detection capability and injecting compensation through the existing PWM control path, the system achieves rapid current settling without requiring separate dedicated compensation hardware or complex external control circuits.
Solution Approach 2:
The compensation pulse injection is merged with the existing PWM control cycle for current regulation. By combining the compensation function with the already-executing PWM control infrastructure, the system achieves rapid current settling while avoiding the complexity of separate compensation control paths, thus integrating multiple functions into a unified control framework.
Data Source
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AI summary
For high frequency injection (HFI) transition disturbance elimination, a processor directs an HFI transition for a motor. The processor determines compensation pulse voltages for an HFI compensation pulse. The processor further injects a sum of the HFI compensation pulse and an HFI voltage into a current regulator voltage output signal for a compensation Pulse Width Modulation (PWM) cycle. The HFI compensation pulse settles an HFI current to a steady state