Rotary Electric Machine Control Apparatus Modulation Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control apparatuses for rotary electric machines do not adequately address single pulse modulation, leading to issues with current ripples and torque shocks due to phase differences between triangular carrier waves and sinusoidal command voltages.
Innovation Solution
A control apparatus that includes a command voltage generator, a carrier signal generator, and a controller to perform pulse-width modulation and single-pulse modulation using a cyclic carrier signal, preventing narrow-width pulses and unnecessary switching by synchronizing peaks and adjusting the number of carrier pulses based on specific equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pulse-width modulation is used with triangular carrier wave, then current ripples are reduced, but torque shocks occur due to phase difference between carrier wave and command voltages
Solution Approach 1:
The patent dynamically switches between pulse-width modulation and single-pulse modulation modes based on operating conditions. The controller selects pulse-width modulation when it provides better current ripple reduction, and switches to single-pulse modulation when torque shock becomes problematic, creating a dynamic adaptation strategy that resolves the contradiction between current ripple reduction and torque shock prevention
Solution Approach 2:
The invention changes the modulation parameter by switching between two distinct modulation modes (pulse-width modulation and single-pulse modulation). This parameter change allows the system to select the optimal modulation strategy for different operating conditions, thereby resolving the contradiction between reducing current ripples and preventing torque shocks
2Object-generated harmful factors
If single-pulse modulation is used, then torque shock is reduced, but current ripples increase due to phase difference issues
Solution Approach 1:
The system dynamically adjusts the modulation mode based on real-time operating conditions. When single-pulse modulation is selected to reduce torque shock, the controller monitors current ripple levels and can switch back to pulse-width modulation when appropriate, creating a dynamic balance between the two competing objectives
Solution Approach 2:
The controller implements feedback control by monitoring both current ripple and torque shock levels, and uses this information to determine when to switch between modulation modes. This feedback mechanism ensures that the system maintains optimal performance by automatically adjusting the modulation strategy based on actual operating conditions
3Manufacturing precision
If modulation mode switching is implemented, then both current ripple and torque shock are controlled, but control system complexity increases
Solution Approach 1:
The controller is designed with multi-functionality to handle both pulse-width modulation and single-pulse modulation within a single unified control architecture. This universal controller implementation reduces the need for separate control systems for each modulation mode, thereby minimizing the increase in system complexity while still achieving both current ripple and torque shock control
Data Source
AI summary
In a control apparatus, a controller performs comparison between a command voltage and a cyclic carrier signal to thereby perform one of pulse-width modulation upon each of first positive and negative peaks of the command voltage being within or identical to the corresponding one of second positive and negative peaks of the cyclic carrier signal, and single-pulse modulation upon each of the first positive and negative peaks of the command voltage being outside the corresponding one of the second positive and negative peaks of the cyclic carrier signal. The pulse-width modulation generates, for each cycle of the command voltage, plural drive pulses based on a result of the comparison. The single-pulse modulation generates, for each cycle of the command voltage, a single positive pulse and a single negative pulse for each cycle of the command voltage based on a result of the comparison.