Skip to content

Pump: integrated power converter

Necessity to include the converter in the pump definition

When a manufacturer requires a power conditioning unit to be used with their pump, they typically specify the converter electrical input rather than the pump's input requirements as operating conditions. Therefore, in these cases, the component black box includes the converter-motor-pump set, and the PVsyst pump model must use the converter as input variables.

This is particularly the case with AC motor pumps, as PVsyst never manages the pump input AC voltage or its frequency. Only the pump power input is a relevant input variable.

This holds indeed for any pump for which the power is specified instead of the current and voltage (Flowrate=f(Power) model).

Converter input

The converter input corresponds to either:

  • A fixed-DC voltage converter: the input voltage should be defined in the controller specifications. On most commercial devices, this is adjustable via hardware. At design time, the controller dialog provides access to the Voltage Optimisation tool for selecting the best suited voltage.
  • A MPPT converter: the minimum and maximum tracking voltages must be specified in the controller dialog.

Like other converters, the maximum and Euro-efficiencies are required to establish the efficiency curve. For simplification, there is no option for defining a customized efficiency profile.

Converter output

As typically specified by the manufacturer, the converter is supposed to perfectly match the pump's input requirements. That is, it will be sufficiently well designed to deliver the optimal voltage/current to the pump at any given time and for the required head, in order to use the available power with optimal efficiency.

The simulation will account for the power limitation due to step-down technology only when the pump's voltage behavior is known in the model. This is the case when the pump model is defined by a set of Flowrate=f(Power) curves, supplemented by additional I=f(U) curves for the pump input.

For positive displacement pumps, the converter replaces the booster, as the starting inrush current is usually required at very low voltage, so the starting power is not prohibitive.