Programmable DC Power Supplies

Overview

The Photovoltaic Power Profile Emulation (PPPE) software automatically calculates solar array voltage and current profiles based on user-defined parameters. These profiles can be sequentially sent to a Magna-Power Electronics' power supply, which will emulate defined characteristics. The user can define a limitless number of profiles to be emulated and sequenced over a given time period.

Key features for the PPPE software are as follows:

• Automatic voltage/current profile calculation from reference parameters
• Autosequencing through power profiles, at user-defined intervals
• Graphical view of profile and real-time power supply output
• Flexible profile generation for manual or automatic operation
• Compatible with Magna-Power Electronics dc power supplies including the: XR Series (2 kW - 6 kW), TS Series III (5 kW - 45 kW), MS Series III (30 kW - 75 kW), and MT Series IV (100 kW - 900 kW+)
• Up to 50 voltage and current points per curve, with piecewise linear approximation performed between points and higher point density around maximum power point

Design and production validation for photovoltaic connected electronics requires a photovoltaic emulating power source with flexible output characteristics. Inverters and specialized dc-dc converters employ maximum power point tracking (MPPT) control algorithms to maximize utilization of nonlinear energy sources, such as solar panels and wind turbines. For development and manufacturing, using photovoltaic arrays for validation is costly with uncontrolled source characteristics. By utilizing a power supply with user-programmable output characteristics, the user can evaluate the full range of power conditions.

Photovoltaic Modeling and Operation

A profile is a voltage/current curve that the power supply’s output should emulate. There are three methods to generate a power profile in the PPPE software:

1. Automatic, based on solar array reference parameters: The user defines the reference parameters provided by the solar array manufacturer. The user only needs to define the new temperature and irradiance values for each profile. The rest of the parameters: maximum power point (Vmp, Imp), open circuit voltage (Voc), and short circuit current (Isc); are all calculated automatically.
2. Automatic, based on maximum power point: The user defines the maximum power point (Vmp, Imp), open circuit voltage (Voc), and short circuit current (Isc). The profile is then generated based on these parameters alone.
3. Manual: The user defines up to 50 current and voltage points for the power supply to emulate. The power supply performs a piecewise linear approximation between points to provide a smooth output curve.

After the profile is defined, it can be transferred to the power supply for either static or dynamic emulation. A time dependent parameter defines how long the power supply should emulate that profile before loading the next profile in the sequence. A user can define an unlimited number of profiles.