Newton N4L Power Analyzer Application Example: Variable-Speed Motor Drive Analysis [PPA3500, PPA4500, PPA5500]

Published: 2022-11-27 Views: 次

A power analyzer is a precision test instrument used to measure the power consumption or generation (in watts) of equipment, circuits, or subsystems. Modern power analyzers can also determine a signal's power factor, harmonic distortion, peak value, average value, and more parameters.

A power analyzer samples the voltage and current waveforms entering or exiting the device under test (DUT). This sampling process typically occurs every 0.5us to 1us, depending on the analyzer model used; some lower-specification models from other manufacturers may sample at as low as 100ks/s. After sampling, the data is processed by a dedicated high-speed digital signal processor (which can also be implemented on modern FPGAs), and various derived parameters are calculated.

An important difference between oscilloscopes/data acquisition cards and true power analyzers is that high-end power analyzers (such as the N4L PPA) can record, store, process and delete samples "on the fly". This means there are never gaps in the sampling process, because the memory buffer is continuously emptied after samples are processed. This is uncommon, but absolutely essential for accurate power measurement.

The N4L power analyzer can transmit raw sample points across the isolation barrier at full resolution. Traditional power analyzers do not transmit this "high-speed" data because the isolation stage is a bottleneck, so other analyzers perform calculations before the data is transmitted to the main CPU card.

The benefit of transmitting raw data samples across the isolation barrier means that the FPGA and DSP can perform inter-phase parallel signal processing across phases. The result is excellent phase accuracy achieved by performing real-time DFT on the raw data samples.PPA5500-TEhas a nominal phase accuracy of 0.003º. A dedicated frequency detection DSP continuously tracks the input frequency and is able to filter the input signals in parallel. This is beneficial when analyzing PWM-type waveforms; in all cases the parallel filtering process does not affect the raw data used to calculate measurement parameters—it only applies filters to the data used for frequency detection.

Our proprietary power analyzer technology gives you extremely high accuracy

There are many power analyzer options on the market offering varying degrees of accuracy, but at the high end of metrology, you can narrow your choice down to a few manufacturers. Every manufacturer will claim their solution is the best, and for good reason, at N4L we refer to hard facts and traceable data to provide our customers with clear, concise and useful metrics to make a decision. We have also developed various application modes and sophisticated power measurement algorithms, which are key to achieving accurate measurements in dynamically changing environments. It is worth noting that achieving accurate measurements using sinusoidal reference waveforms in a calibration environment is much easier than in distorted, dynamically changing motor drive or LED power measurement applications. With this in mind, N4L, together with the University of Oxford (UK), developed a 2MHz calorimetric-principle-basedISO17025certified watt calibrator, utilizing a unique liquid heat transfer medium to enable rapid calibration of test equipment. This research provided us with a world-leading watt reference up to 2MHz and highlighted our design philosophy of designing products that perform as well in real-world applications as they do on the calibration bench. The industry's obsession with headline specifications often leads instrument designers to overlook what really matters - accurate measurement in real-world environments where distorted waveforms and broadband power exist.

Key reasons to choose N4L:

• Best high-frequency performance on the market – key to accurate power measurement of devices containing high distortion/switching frequencies

• Best phase accuracy on the market – traceable toISO17025

• Best CMRR (common mode rejection) on the market – very important for floating differential measurements, e.g. when measuring current at high common mode potential

• The only power analyzer manufacturer offering power calibration up to 2MHz, throughISO17025 Certification

• Designed and manufactured in the UK, compliant withISO9001：2015Quality standards

• Excellent low-power standby measurement, compliant with IEC62301

• Compliant with IEC61000-3-2, IEC61000-3-3, IEC61000-3-11and IEC61000-3-12

• Frequency synchronization range from 10mHz to 2MHz (PPA5500)

Variable speed motor drives have become the technology of choice for motor control in many industries. From industrial automation, utility waste transport, large-scale traction drives to today's electric vehicle market. In particular, variable speed variable frequency drives pose a huge challenge to power analyzers in terms of accurate power measurement. The PPA3500,PPA4500 and PPA5500was designed with this in mind.

Key measurements provided by N4A PPA:

• AC input to DC bus power efficiency

• DC bus to inverter output power efficiency

• Electrical to mechanical efficiency using torque and speed inputs

• Current waveform distortion analysis

• Simultaneous measurement of broadband and fundamental electrical parameters

• Connect to high-current external sensors such as LEM zero-flux sensors.

• Completing the signal chain'sISO17025system calibration, including; PPA, interface box and external current sensors

• Complex parallel frequency filtering for dedicated frequency-tracking DSP, providing fast frequency tracking during acceleration/deceleration

All N4L PPA series power analyzers are capable of measuring LED driver efficiency and power quality, and the PPA range can analyze the following parameters;

• AC input to DC output power efficiency

• DC Input to DC Output Power Efficiency

• Independent DC component and AC ripple voltage analysis

• Surge Analysis

• PPA3500 – Simultaneous Power and Integrator/Oscilloscope Analysis

• Extremely Low Signal Sensitivity

• Fast Measurement Updates Down to 2ms

• High sampling rate ensuring wide measurement bandwidth

Why choose N4L power analyzers for LED driver analysis?

• All instruments areISO17025Certification

• N4L offers the fastest update rates in their class

• Maximum Sampling Rate Always Maintained Regardless of Update Rate

• PPA can separate DC component and AC ripple

• Seamless analysis ensures all data is analyzed

• Extremely stable measurements even at low signal levels

The N4L PPA series power analyzers provide a highly accurate solution for standby power consumption analysis, with custom-designed software enabling users to easily perform fast, simple, compliant measurements. Every N4L power analyzer is UKASISO17025certified, giving users ultimate confidence that measurements are correct and traceable.

Standby power measurement overview

• ISO17025Traceable measurements

• Compliant with EN50564 + IEC62301 standards

• AC power sourceAlso available from N4L

• Start, stop + report functions from the custom-designed software package – provided free with every instrument

• The software can also analyze AC power supply compliance during testing

• Cyclic, non-cyclic, variable power and limited-duration modes all meet

• Breakout boxEnables simple, safe connections

PPA55x1 (fully compliant) and PPA5530 (pre-compliant) provide compliance testing to the latest standards IEC61000-3-3, IEC61000-3-2, IEC61000-3-11 and IEC61000-3-12. N4L has developed comprehensiveISO17025calibration protocols, available on request, to cover all aspects of IEC61000 harmonics and flicker. In particular, the d(t) testing performed as part of N4L's IEC61000ISO17025(UKAS) calibration protocol is an industry first, as coverage of d(t) testing within an accredited calibration procedure is extremely rare.

• The industry's most comprehensiveISO17025Accredited Calibration

• You deal directly with the manufacturer of the flicker meter/harmonic analyzer, not a system integrator

• High precision

• Also availableAC power source和Impedance network

• AC power sources can be calibrated on-site via the PPA – no need to ship AC power sources for calibration

• The PPA verifies AC power source compliance during IEC61000 testing

• The PPA can also be used as a general-purpose/development power analyzer in many applications

• Currents up to 50Arms can be accepted internally by the PPA, with external current sensors for higher currents

The N4L PPA5500-TE was developed specifically for the transformer testing and development industry, with 0.02% reading + 0.02% range error, the PPA5500-TE is the market leader and reference in transformer testing. One of the key design features that gives the PPA5500-TE such a performance advantage is its current shunt design; this proprietary design enables the PPA5500-TE to achieve 0.003 degree phase accuracy. No other power analyzer on the market performs so well in this area, which is a critical performance parameter for measurements at low power factor – for example during load core loss analysis.

PPA5500-TE Overview;

• Compliant with IEC60076-1

• 0.003 degree phase accuracy

• Watt accuracy of 0.55% at PF = 0.01

• All accuracies areISO17025Certification

• 3-year warranty

• Highly Stable Measurements

• Interfacing with external voltage/current sensors

• Harmonic analysis

• 与ADI40Temperature/DC sensor interface compatible

The PPA4500 and PPA5500 have market-leading phase accuracy, making them ideal for inductor (choke) loss analysis at low and high frequencies. The typical power factor during inductor loss analysis is very low, because calculating the correct watt dissipation of an inductor or choke places high demands on precisely measuring the phase shift between voltage and current.

Why choose PPA for inductor loss analysis?

• Market-leading low power factor performance

• Capable of measuring extremely low watt values over a wide VA range

• Bandwidth up to 2MHz (PPA5500)

• Excellent dynamic range

• High common-mode rejection ratio (150dB), essential for floating current measurements above high-frequency noise

• Internal current measurement range up to 50Arms

Evaluating solar inverter systems requires instruments to be synchronized with both the DC waveform (the solar cell output) and the AC waveform (the inverter output). This means the analyzer needs at least two independent frequency measurement channels, and all PPAs are capable of such measurements. In addition, it is essential that the power analyzer acquires data synchronously from each channel. This ensures that power measurements and subsequent efficiency measurements are made using data occurring within the same time window; power analyzers typically do not acquire data synchronously from each channel, resulting in incorrect efficiency measurements. All N4L power analyzers can also be used for harmonic analysis of inverter output waveforms to verify compliance with relevant standards.

Why Choose N4L Analyzers for Solar Inverter Analysis?

• Excellent DC accuracy for solar cell power measurement

• AC+DC coupling, enabling separate evaluation of DC and AC content

• Harmonic analysis to ensure inverter output distortion compliance

• Synchronous measurement of each input channel, ensuring time-aligned power and efficiency measurements

• Fast acquisition option for transient analysis

• Continuous 2Ms/s (PPA5500) high sampling rate, independent of window size and update rate

• ISO17025Accredited Measurement Standards

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