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TDEMI - 645 MHz Real-time Analysis Bandwidth for Full Compliance Testing

TDEMI - 645 MHz Real-time Analysis Bandwidth for Full Compliance Testing


Realistic Simulation

Whatever solar array simulator you use, the simulation must be as realistic as possible. For example, many PV inverters generate AC ripple on the DC connected to the photovoltaic array. For single‐phase inverters, the frequency of this ripple is twice the line frequency (100Hz). An increasing number of inverters (and virtually all micro‐inverters) accurately measure amplitude and phase of the ripple voltage and current to quickly track the MPP of the array.

This approach allows the inverter to track the MPP at a much higher speed when compared to conventional dithering techniques (also called perturb and observe). Faster tracking of the MPP results in a much higher overall efficiency in cloudy conditions, where the irradiance is constantly changing. It is likely that all solar inverters will use this approach in the near future, since end-users are very sensitive to the overall efficiency of their solar energy installations.

The simulator’s power supplies must not suppress this ripple as a function of their regulation loop. To perform the most effective test, the solar array simulator must be capable of reproducing the voltage / current behaviour of a solar array even in the presence of this ripple.

This is just one of the parameters that you must consider when selecting a solar array simulator. For more information on solar array simulators and what to look for when choosing them, contact Fuseco, your trusted partner in programmable power solutions.

More about the Elgar TerraSAS

The TerraSAS consists of programmable DC power supplies, a rack mounted controller, keyboard and LCD display with control software and GUI interface, output isolation, polarity reversing relays and a unique PV simulation engine that controls the power supply. This combination of hardware allows the TerraSAS to simulate most test protocols or combination of events that a solar installation will be subjected to. Power supplies are available in 1-15KW increments to simulate arrays up to 1MW.

Measurements of radiated emissions in the frequency range up to 1 GHz are performed in a semi-anechoic chamber or on open area test sites (OATS). Such measurements are very time consuming as according to CISPR and FCC Standards the measurements have to be performed at several antenna heights and all angular positions of the device under test.

In the past the total test time was reduced by performing pre-scans with peak detector and short dwell times and final maximisation carried out at individual frequencies only. During the pre-scan procedure overview measurements are performed to search for the frequencies with maximum emissions. A list of suspicious frequencies (peak list) is generated. Then at these frequencies the final measurement is performed in single frequency mode with longer dwell times.

Using the GAUSS INSTRUMENTS TDEMI X with a real-time analysis bandwidth of 645 MHz and fully gapless evaluation and visualising, the final maximisation can be performed at all frequencies simultaneously.

The unique feature of the fully gapless real-time spectrogram mode combines all the advantages of the single frequency mode of a traditional receiver with the possibility to carry out the measurement at all frequencies simultaneously. Two detectors are applied simultaneously, thus CISPR-Average and Quasi-peak detectors can be measured simultaneously in real-time and stored and visualized in real-time.

Fully gapless processing and evaluation of all frequencies is given, which is a mandatory requirement of CISPR 16-1-1 Ed. 3. Fulfilling all the requirements of the CISPR 16-1-1 2007 till the current version of CISPR 16-1-1 entirely, thus the real-time spectrogram mode can be used for final maximization either for product standards that reference older CISPR 16-1-1 versions or also the current version of the CISPR 16-1-1 version that contains the inclusion of the “FFT-based measuring instrument”.

By applying the real-time analysis bandwidth of 645 MHz the measurement is carried out first in the frequency range of 30 MHz – 645 MHz using Quasi-peak and CISPR-Average detectors including maximization at all angular positions and heights. After characterization in the range from 30 MHz – 645 MHz the second full maximization is performed in the range 645 MHz – 1 GHz. Both measurements are combined to the final test report.

The final test result contains all the measurements of Quasi-peak and CISPR-Average at all frequencies over all positions as well as the maximum emissions. Now, the overall test time corresponds approximately to the test time of a final maximization carried out at two critical frequencies according to the traditional pre-scan and final maximization procedure which was performed in the past. In Addition the total measurement quality is improved and the measurement uncertainty is reduced performing the measurement in the TDEMI X real-time spectrogram mode.

The advantage of using this method is that all operation modes of a device under test can be easily measured in a very short total test time. Complicated test procedures resulting in increased measurement uncertainty are now a thing of the past. Fast and reliable testing is of crucial importance to address today’s short time-to-market cycles.

It is not necessary anymore to perform pre-scan and final maximisation. In addition, evaluation according to the limit lines as well as report generation is performed by the instrument creating a report in MS Word file format which can be integrated into larger documents. Using full automation software such measurements can be also performed fully automated, and radiation patterns and further evaluations can be included in the test report.

645 MHz Real-time Measurement visualized in a 3D Plot

Gauss Instruments……….Synonymous for highest quality.


GAUSS INSTRUMENTS develop and produce high quality instruments made in Germany that utilise cutting edge technology to fulfil the requirements of complex measurement tasks. Their goal is to provide an additional benefit by accelerating test and measurement procedures, continuously increasing performance parameters and providing high quality measurement results to their customers. Founded in 2007, the company is a spin-off from the Institute for High-Frequency Engineering of the Technische Universität München.

The research in the field of time domain measurements of electromagnetic interferences (EMI) started in the year 2000 and in the following years resulted in over 50 publications, transactions and journal articles being published on the topic of time-domain EMI measurements.

GAUSS INSTRUMENTS is the manufacturer of the award winning TDEMI Measurement System that uses ultra-high-speed analogue to digital converters and real-time digital signal processing systems to enable ultra-fast tests and measurements for electromagnetic compliance that fulfil the demand for measurements of today’s complex electronic equipment and applications.

The presentation of the first TDEMI Measurement System (TDEMI 1G) at the EMC Zurich 2007 Conference in Munich, was the beginning of what was to become a highly respected product range which covers a wide range of the demands of modern EMC testing.

Customised signal processing solutions are also offered based on their established hardware and software platforms. Using their expertise about real-time digital technology and microwave technologies they are developing systems that are unique in the field of test and measurement.

For further information, please contact Fuseco, your trusted partner in programmable power solutions.

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