Power analyzer

The power analyzer is mainly used to measure the power and efficiency of power conversion devices such as motors, inverters and transformers. It is widely used in power calculation and analysis of hybrid electric vehicles, electric vehicles, solar power, wind power, inverters, variable frequency motors and fuel cells. Some analyzers, such as the WP4000 variable frequency power analyzer, also have real-time waveform, waveform data recording and harmonic analysis.

The difference between power analyzer and power meter

In a nutshell, the power analyzer is an upgrade of the power meter, including the active power measurement function of the power meter, and has a stronger function and a wider application range.
Functionally, power meters can only be used for power measurements in sinusoidal circuits. Even a power meter that can measure the power of a non-sinusoidal circuit can only measure the voltage, current true rms, and total active power.
In the practical application of non-sinusoidal electric power measurement, in addition to the voltage, current true rms value and total active power, we also want to know the fundamental rms value of voltage and current, the total harmonic content, the amplitude of each harmonic, Fundamental power and power of each harmonic.
The power analyzer measures the active power of sinusoidal and non-sinusoidal circuits, as well as the fundamental and harmonic power of non-sinusoidal circuits.
In other words, the former mainly deals with sinusoidal signals, the latter can handle sinusoidal and non-sinusoidal signals.
In other words, the former has a weaker processing function for non-sinusoidal signals, and can only view its approximate (true rms value and active power of the signal). The latter can understand the detailed structure of the signal (harmonic amplitude and harmonics) through frequency domain analysis. power).
The characteristics of frequency domain analysis are accurate but too abstract. Frequency domain analysis allows us to accurately quantify the internal structure and details of the signal, but it is not intuitive enough!
Observing real-time waveforms can visually understand unknown complex signals at the fastest speed and establish perceptual knowledge. In many cases, the observed waveforms can be used for fault diagnosis or interference elimination. Real-time waveforms belong to time domain analysis.
Based on the above requirements, the power analyzer should have the functions of time domain analysis and frequency domain analysis in addition to the voltage, current rms measurement and total active power measurement of the power meter.

Power Analyzer Ranking

No1, WP4000 variable frequency power analyzer on the list reason: WP4000 variable frequency power analyzer is a low-key brand, so that the brand has been developed for many years has not been known, but its measurement concept is the most suitable for variable frequency measurement However. The fiber-based front-end digitization technology can solve the powerful electromagnetic interference in the transmission process of variable frequency measurement; the wide range direct measurement technology of 100μV~15kV voltage and 100μA~7kA current solves the problem of shifting multiple sets of sensors; system accuracy, global precision, relative The precision nominal method of precision is the most realistic precision nominal method made entirely from the user's point of view; for the moment, the WP4000 variable frequency power analyzer is in DC, 0.1Hz~1500Hz fundamental frequency range, type A power The unit's system accuracy can reach 0.05% rd, which is unmatched by other power analyzers.
No2, Norma5000 high-precision power analyzer on the list of reasons: Fluke as a globally renowned brand, has a deep heritage in the electronic measurement industry. Fluke introduced the Norma 5000 broadband power analyzer after acquiring the D6000 power analyzer from LEM, Switzerland. The Norma5000 high-precision power analyzer has a maximum sampling rate of 1MHz (depending on the power module, PP50 and PP51 is 1MHz). It is ahead of other power analyzers. The accuracy of the fundamental frequency measurement range below 1000Hz can reach 0.05% rd+0.05%Fs (PP50, PP51, PP52, PP54) is also an amazing indicator. In contrast, its human-machine interface is not in line with the nationals, and the appearance lacks the solid sense of FLUKE's authentic lineage.
No3, WT3000 high-precision power analyzer list reasons: As the highest-end power analyzer in Yokogawa, WT3000 high-precision power analyzer once occupied the market share of the high-end power analyzer market. The basic power accuracy of 0.02% rd+0.04% Fs does allow many power analyzers to only look back, but this accuracy is limited to the sine wave range of the power frequency (45Hz~66Hz), and the accuracy of other frequency bands has a significant drop. However, as a high-end machine of Yokogawa for centuries, the list is a must.

Power analyzer principle

The traditional active power meter is usually designed for power frequency or medium frequency sine wave measurement, so it can only meet the active power measurement of the sine wave circuit. When the waveform distortion is small, the accuracy of the nominal measurement can be obtained. When the waveform distortion increases. The measurement error increases and even the normal measurement function is lost.
The power analyzer is a function upgrade product of the active power meter, and generally has the following functions:
1, with the basic functions of the power meter: voltage, current true RMS and total active power measurement;
2. Extend the applicability of the basic functions of the power meter to measure the voltage, current true rms and total active power of the sinusoidal and non-sinusoidal circuits. Generally required to adapt to a wider bandwidth and a wider range of fundamental frequency;
3. Ability to enter qualitative and quantitative analysis of detailed information contained in non-sinusoidal voltages, currents, and power.
Qualitative analysis is generally based on an intuitive time domain analysis method, which is based on real-time waveforms. Quantitative analysis is generally based on an abstract but accurate quantitative frequency domain analysis method, which is based primarily on the Fourier transform.

Power Analyzer Application

For the case where the frequency deviates from the power frequency and the voltage or current is obviously distorted, the traditional transformer and power meter measurement often cannot guarantee the accuracy of the measurement. Power analysis with wide frequency band and digital signal processing function should be adopted. It is measured by a system consisting of a wide-band, low-angle, high-precision voltage and current sensor.
1. Evaluation of motor energy efficiency For the development of high-efficiency motors represented by hybrid vehicles, it is possible to accurately measure the power, efficiency and harmonics of the converter.
2. New energy measurement power converter input DC power, output AC power and harmonic analysis according to the characteristics of PWM wave harmonic distribution, total harmonic distortion rate calculation. Through DC and AC power calculations, power consumption and power generation can be measured simultaneously, and energy efficiency can be accurately evaluated.
3. The inverter test passes the variable frequency power sensor, which can simply perform the power measurement of the inverter input measurement and the inverter output measurement on the spot, and perform harmonic analysis in accordance with the harmonic distribution characteristics of the PWM wave.
The main circuit structure of the inverter is generally “AC-DC-AC”. A large capacitor is connected in the rectifier circuit. The input current is a pulsed charging current. The output voltage signal in the inverter output loop is a pulse waveform modulated by the PWM carrier signal. . Therefore, the choice of measuring instruments is different from the traditional ones. In the face of the inverter containing a large amount of harmonics, high distortion or non-power frequency, the measurement with traditional instruments will produce large errors, and even the measurement results are completely wrong. The accurate measurement method is to use FFT. Functional instrument.
4. Transformer test transformer no-load test, its current waveform distortion rate is large, the input current distortion rate of the rectifier transformer is large, these high distortion rate currents are rich in high-order harmonics, and its energy efficiency evaluation test should adopt wide-band Sensors and power analyzers make accurate measurements.