Real-Time Modeling Tools
RT-EVENTS is a Simulink toolbox for fixed-step simulations of hybrid systems involving dynamic and discrete events that are asynchronous with respect to the simulation clock. It allows the simulation of high frequency modulation signals of firing pulse units and power electronic controls.
The RT-EVENTS Blockset works with a fixed time-step, making it compatible with the Simulink Coder and Embedded Coder and RT-LAB, and can be used for real-time applications.
Features
Improved Accuracy for Discrete Simulation of Event-Based Systems
- Compensates for errors introduced when events occur between samples
- Accuracy depends on the time-step selected with respect to the frequency content of continuous signals
- Simulates high frequency modulation signals used in power electronic controls
Rapid Simulation of Event-Driven Systems
- No iteration, uses fixed time-step algorithm
- Faster simulation than variable-step algorithms
- Supports distributed real-time simulation
- Suitable for hard real-time applications such as hardware-in-the-loop or embedded simulations
- Compatible with Simulink and Simulink Coder and Embedded Coder
Using RT-EVENTS
The RT-EVENTS Blockset provides a solution to typical problems encountered in the simulation of event-based systems:
Long Simulation Times
- The simulation of event-based systems requires time consuming variable-step algorithms, revealing the limitations of current visual simulation tools, such as Simulink
- Code generators do not support variable-step algorithms
Imprecise Hard-Real-Time Simulation
- Variable time-step algorithms cannot be used for hard real-time simulations
- Limitations of discrete simulation algorithms
- Errors for event-based systems when events occur between the sampling instants
- Require sampling periods and/or interrupt response latencies smaller than the specified timing precision of critical events: for example, 10us for a combustion engineer
Typical Applications
Complex Hybrid Systems
The use of variable-step solvers carries the disadvantage of significantly slowing the simulation of complex converter controls. The use of fixed-step solvers improves simulation speed, but often provides incorrect results due to delays for discrete events (asynchronous with the simulation step) to the next simulation cycle, causing an accumulation of errors and phase shifts.
Hybrid & Electrical Transportation
Only fixed-step solvers are used for automatic code generation. Standard fixed-step solvers for Simulink yields errors, which are then applied to converter controls; this may accumulate and cause drift and significant phase shift. RT-EVENTS applies a compensation algorithm to discrete events in real-time, resulting in a greater precision.
Power Electronics
When rapid prototyping power electronic systems, it can be challenging to convert controller outputs to switching signals sent to time-stamped digital outputs. The use of standard Simulink blocks causes high jitter, due to the lack of any timing information: when simulated at fixed-step in the order of 10us to 100us, the firing pulses cannot be generated precisely. RT-Event generates timing information about the switching and state transitions to each switching state, ensuring more precise results.
