Switched Reluctance Motor Controller Using Dedicated Timer Module
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current control methods for switched reluctance motors, such as those using digital signal processors (DSPs) with polling input/output, face limitations in timing resolution due to clock cycle constraints, leading to temporal jitter and processing overhead, which is problematic for high-speed applications requiring accurate timing.
Innovation Solution
A controller system for switched reluctance motors that uses a combination of polling and interrupt-driven input/output methods, employing a clock signal to modulate energy delivery to stator windings based on rotor position and speed, with a flux reference and characteristic look-up tables to determine and adjust flux, allowing for precise control in various operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If polling driven input/output is used in DSP to control SR motors, then the system is simpler to implement, but timing resolution is limited due to clock cycle constraints
Solution Approach 1:
The patent segments the control system into two distinct parts: a DSP that handles high-level control decisions and a separate timer/counter module that handles precise timing measurements. This segmentation allows the DSP to operate with simpler polling I/O while the dedicated timer module provides high-resolution timing without burdening the main processor, thus resolving the contradiction between system simplicity and timing precision.
2Measurement precision
If the clock period is reduced to improve timing resolution, then timing precision improves, but processing overhead increases heavily
Solution Approach 1:
The patent introduces a dedicated timer/counter module as an intermediary between the DSP and the motor control signals. This intermediary handles the high-frequency timing operations and pulse generation, allowing the DSP to maintain a higher clock period for processing while the timer module independently provides the fine timing resolution needed for motor control, thus avoiding the processing overhead penalty.
3Measurement precision
If interrupt driven systems are used to avoid temporal jitter, then timing accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the interrupt handling functionality from the main DSP control loop and delegates it to a dedicated timer/counter module that operates independently. This extraction allows the system to achieve interrupt-driven timing accuracy for critical motor control functions while keeping the main DSP control logic simpler and less complex, as it doesn't need to implement full interrupt handling infrastructure.
Data Source
AI summary
A method of controlling a switched reluctance motor is disclosed herein. The motor comprises a stator carrying a plurality of phase windings and a rotor. The method comprises activating the phase windings in a sequence selected to apply torque to the rotor, wherein during a cycle of rotation of the rotor the phase windings switch between an active state in which current in the phase winding applies torque to the rotor and an inactive state; applying a voltage to a selected phase winding whilst the selected phase winding is in the inactive state to provide a flux in the selected phase winding; determining the current in the selected phase winding; determining the rotor angle based on the current and the flux; and controlling said activating based on the rotor angle.