Pulse-Width Modulated Signal Sequence Generation in Automation Systems
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Solution Overview
Problem
Existing methods for generating pulse-width modulated signals in automation systems suffer from a dead time between setpoint calculation and signal output, particularly when connected via a field bus, leading to inefficiencies and fluctuations.
Innovation Solution
Synchronizing the generation of the signal sequence with the arrival of new target values, ensuring that a new period begins at or shortly before its intended time, and using a synchronization means connected to the field bus clock to minimize dead time and filter transient processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If pulse width modulation is used with field bus connection for automation control, then communication and control capabilities are improved, but dead time between setpoint calculation and signal output increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple PWM signal sequences in advance before they are actually needed. The microcontroller prepares a buffer of pre-calculated PWM sequences that can be immediately output when required, eliminating the dead time between setpoint calculation and signal output while maintaining full automation control capabilities through field bus connection.
2Ease of operation
If setpoint calculation is performed cyclically in automation device, then control algorithm execution is simplified, but synchronization with PWM period boundaries becomes difficult
Solution Approach 1:
The system performs preliminary calculation of PWM signal sequences in advance and stores them in a buffer. This allows the control algorithm to execute cyclically without worrying about synchronization timing, as the pre-calculated sequences are ready to be output immediately when a period boundary is reached, maintaining both ease of operation and synchronization precision.
Solution Approach 2:
The patent introduces an intermediary buffer memory that decouples the setpoint calculation process from the PWM output process. The buffer acts as a mediator that stores pre-calculated PWM sequences, allowing the control algorithm to run independently on its schedule while ensuring synchronized output at the correct PWM period boundaries.
3Speed
If new setpoint values are calculated continuously, then responsiveness to process changes is improved, but dead time before new PWM signal output increases
Solution Approach 1:
The system continuously pre-calculates and stores multiple PWM signal sequences in advance in a buffer, even before new setpoint values are immediately needed. This preliminary preparation ensures that when a new setpoint is required, the corresponding PWM sequence is already ready for immediate output, achieving both high responsiveness and zero dead time.
Data Source
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AI summary
The method involves switching output voltage during a time period (T) between values (U1, U2). Time duration is determined using predetermined desired values (1) while receiving the output voltage. A generation of a pulse width modulated signal flow is synchronized with desired value calculation of the desired values. The desired value calculation is performed in an automation apparatus, where the desired value is provided at time point corresponding to an integer multiples of the time period. An actuating element is controlled by the signal flow with the determined time duration. An independent claim is also included for a device for outputting a pulse width modulated signal flow, comprising a signal flow generating unit.