AC Rotary Machine Control Modes for Ripple and Switching Loss
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Solution Overview
Problem
Existing AC rotary machine controllers face challenges in reducing the ripple component of the bus current and winding current, leading to increased losses due to mutual inductance and output interval issues in voltage vector management.
Innovation Solution
An AC rotary machine controller that switches between three control modes based on operating states: phase current ripple suppression, bus current ripple suppression, and switching loss suppression, using a voltage command calculation unit to modulate voltage command values and control switching devices in inverters to minimize ripple components and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If different carrier wave signals are used for different phases to suppress bus current ripple, then bus current ripple is reduced, but switching loss increases
Solution Approach 1:
The control system dynamically selects between first control mode (same carrier wave signal for all phases, lower switching loss) and second control mode (different carrier wave signals, lower bus current ripple) based on operating conditions. This dynamic switching resolves the contradiction by applying the appropriate control strategy for each operating scenario.
2Loss of energy
If constant loss calculation and comparison is performed to select minimum loss drive method, then optimal efficiency is achieved, but processing load increases
Solution Approach 1:
The system dynamically switches between control modes based on operating conditions (rotation speed, torque, temperature) rather than continuously calculating and comparing losses. This dynamic approach achieves near-optimal efficiency by selecting appropriate control modes while significantly reducing the processing load compared to constant loss calculation methods.
Solution Approach 2:
The patent changes control parameters (carrier wave signal configuration, control mode selection) based on operating conditions such as rotation speed, torque, and temperature. This parameter-based control strategy achieves efficient operation without requiring continuous loss calculation and comparison, thereby reducing processing load while maintaining optimal performance.
Data Source
AI summary
To provide an AC rotary machine controller, a vehicle apparatus, and an electric power steering apparatus which can achieve appropriately reduction of the ripple component of the bus current, reduction of the ripple component of the winding current of each phase, or reduction of the switching loss. An AC rotary machine controller controls an AC rotary machine provided with one set or a plurality of sets of three-phase windings; switches a first control mode, a second control mode, and a third control mode, based on an operating state of the AC rotary machine, for each set; executes a phase current ripple suppression control in the first control mode; executes a bus current ripple suppression control in the second control mode; and executes a switching loss suppression control in the third control mode.