RMS measurements

Description of the Voltage RMS and Current RMS components in Schematic Editor, which measure the root mean square (RMS) values

In real-time/VHIL simulation, these types of measurements use the so called DSP solver part of the processor. The same solver is used for power sources and thermal models. Number of RMS measurements is not strictly limited.

Figure 1. Voltage RMS component in Typhoon HIL Schematic Editor
Figure 2. Current RMS component in Typhoon HIL Schematic Editor

Ports

  • p_node (electrical)
    • Positive port of RMS measurement.
  • n_node (electrical)
    • Negative port of RMS measurement.
  • out
    • Available if the Signal output property value is set to True.
    • Output signal port of the RMS measurement.
      • Supported types: real
      • Vector support: no

General (Tab)

  • Operation mode
    • Sets one of two operation modes of RMS measurements: PLL based and Fixed frequency.
    • PLL based mode is more general, and it adapts in real time to the signal frequency. This mode should be used in case of variable frequency signals. In case the measured signal is significantly distorted built-in PLL may fail to lock resulting in inconsistent readings.
    • In Fixed frequency mode RMS value is measured with predefined fundamental frequency, defined by value set in the Fundamental frequency parameter.
  • Fundamental frequency
    • Available if the Operation mode property value is set to Fixed frequency.
    • Sets the fundamental frequency of the measured signal. [Hz]

Signal Processing (Tab)

  • Pin to System CPU
    • If Pin to System CPU is checked, signal processing code in the component will be mapped to the System CPU. In this case, execution rates for signal processing code inside the component are defined in the Signal processing settings.
    • If Pin to System CPU is unchecked, signal processing code in the component will be mapped to the CPU according to standard CPU partitioning algorithms. More about this algorithm can be found in the Signal processing settings. In this case, it is possible to specify Fast and Slow execution rates.
    • In TyphoonSim, all signal processing code is mapped to a single platform, and is partitioned according to execution rates.
  • Fast execution rate
    • Available if the Pin to System CPU checkbox is unchecked.
    • This execution rate sets the sampling rate of the measurement signal. [s]
  • Slow execution rate
    • Available if the Pin to System CPU checkbox is unchecked.
    • This execution rate applies to the analog output signal name.rms. If the signal output port is enabled, the output execution rate is the same as Slow execution rate. [s]
  • Signal output
    • If the property value is set to True, the measured RMS value is available on a dynamically added output signal port.
  • Output execution rate
    • Available if the Signal output property value is set to True, and Pin to System CPU is checked.
    • Sets the output execution rate. [s]

Advanced (Tab)

  • Exact measurement
    • If checked, the measurement is calculated as a state variable. In some corner cases, where there are very fast time constants (<1e-5s), enabling exact measurement will give more accurate results.
    • Exact measurement option is not supported in TyphoonSim and changing its value will not affect TyphoonSim simulation.
Drawbacks using exact measurements are:
  1. Might increase the memory usage,
  2. Might require more processing power which may result in a larger required simulation step.

Extras (Tab)

The Extras tab gives you the opportunity to set Signal Access Management for the component.
Signal visibility is calculated based on the 'signal_access' property and whether or not a parent component in its hierarchy is locked or not. Components that are not contained within locked components expose their signals regardless of the 'signal_access' property. The 'signal_access' property can have one of three values:
  • Public - Components marked as public expose their signals on all levels.
  • Protected - Components marked as protected will hide their signals to components outside of their first locked parent component.
  • Inherit - Components marked as inherit will take the nearest parent 'signal_access' property value that is set to a value other than inherit.

Analog output signals from voltage and current RMS measurements

Analog output variable name Description
name.rms RMS measurement
name.instantaneous Instantaneous measurement