How fast is your DC Power Supply?

In this blog, we delve into the speed capabilities of a high-power DC supply.

We have seen a growing number of applications where dynamic response from DC supplies and loads is needed. Most prominently in battery charge and discharge applications to verify how they perform under dynamic load. Other applications that benefit from dynamic capabilities are power conversion systems like inverters and DC motor testing.

While benchtop supplies handling a few hundred Watts exhibit agility, the real test lies in the performance of a robust device. For our assessment, we've opted for the IT-M3912C-800-48, boasting a substantial 12kW output, with a maximum capacity of 800V and 48A. Given its significant output capacitors, functioning akin to a low-pass filter, conventional expectation would deem it considerably sluggish. Let's conduct measurements to ascertain its operational capabilities.

From a design point of view, we try to avoid excessive speed in the power supply, as this can lead to a tendency for the output voltage to become unstable. For this test we connect an oscilloscope to the output terminals with no additional load:

We than perform an output voltage change from 0V to 50V.

The IT-M3912C accomplishes a transition from 0 to 100% in under 100ms, a remarkable feat given its 12kW capacity. However, it's essential to note that measurements can fluctuate based on the load and voltage variations. The test conducted from 0 to 50V without a load offers an approximate range of what we might anticipate.

As the IT-M3912C has a lot of features (see below), we can also perform an ARB sweep (Arbitrary Waveform Sweep) with a sinusoidal waveform from 1Hz to 20Hz. We will see at what frequency the signal still resembles a clean sine wave. For the amplitude we choose 20Vpp. We can reuse the test-setup from test 1 and capture the results with the oscilloscope.

To see if the frequency is correct, we can zoom in on the 1 Hz and 20 Hz parts of the signal.

The result: The IT-M3900C generates accurate frequencies. Again, this is an impressive performance for a DC supply that is not optimised to generate AC signals.

As we can see, the waveform starts to distort at 20Hz, so let's see what frequency still produces a reasonably clean signal.

Like in test 1 this test will yield varying results depending on output load and voltage swing.

However, we can get an indication for what is possible with a modern high-power bi-directional Power supply like the new IT-M3900C series.

A non-conclusive list of features for the IT-M3900C, affordable and fully protected:

• Small! Up to 6kW in a 1U unit, up to 12kW in a 2U unit.
• Up to 1020A source / 720A sink and up to 1500V in a single unit.
• Seamless parallel operation of up to eight 12kW units.
• Regenerative E-Load.
• Seamless Source- / Load-Mode transition.
• Standard USB / CAN / LAN / digital IO interface, optional GPIB & RS-232.
• Built-in Goodies:
  • List mode: 10 Lists, 200 steps each.
  • Function Generator & Arbitrary waveforms (sinus, pulse, CDWell & user defined).
  • Battery charging / discharging function.
  • Battery simulation function.
  • Photovoltaic I/V curve simulation (85V and 150V models).
  • Built-in voltage curves comply with LV123, LV148, DIN40839.
  • Built in automotive test waveforms: ISO-16750-2, SAEJ1113-11, LV124 and ISO21848.
  • Dynamic drive profile simulation function with up to 10’000’000 points.Adjustable rise & fall times.
  • Many more..

The device can be operated from the front panel, over LAN via the virtual front-panel, by using the (free) IT9000-PV3900 remote control software, by providing List files in CSV-format via the front-panel USB connector or via SCPI-commands via any of the available interfaces.

Additionally, ITECH offers Software packages for Battery-Test, PV-Simulation and Fuel-Cell simulation.

The new ITECH IT-M3900C Series of Bidirectional Power-Supplies are feature-packed for a very competitive price. Do not hesitate to talk to our technical experts about your specific application and requirements.

We have the expertise and a carefully selected product portfolio available to fulfill your requirements and support your visions with power supplies, E-Loads, Instruments and more. Talk to us.