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Traditional wattmeters mainly measure electrical parameters as voltage RMS, current RMS and active power. In addition to the above parameters, the power tester generally also requires the measurement of fundamental voltage RMS, fundamental current RMS, fundamental active power and harmonic voltage, harmonic current and harmonic power.

Since there are many parameters to be measured by power analyzer, and some parameters need to be processed based on digital signals such as digital filters and Fourier transforms, power anaylzers are mostly based on AC sampling technology, and various parameters that need to be measured are acquired by AC sampling. The digital sample sequence is obtained by correlation operation. For example, the true effective value can be obtained by performing root-mean-square operation on the digital sample sequence of one signal cycle of the measured voltage, and the Fourier transform can be used to obtain the fundamental wave effective value, harmonic amplitude and phase of the measured voltage, and further operation Harmonic distortion, harmonic content, and more can be obtained.

Power analyzer generally also includes the functions of a harmonic detector or a harmonic analyzer and a real-time oscilloscope.

Power tester is a title in recent years. It generally refers to instruments and meters that mainly measure active power, commonly known as power meters or wattmeters. Traditional wattmeters mainly measure electrical parameters as voltage RMS, current RMS and active power.

In recent years, the power electronics technology represented by frequency conversion speed regulation has developed rapidly. The measured electrical signal has evolved from the traditional 50Hz sine wave to a variable frequency electric quantity with a wide fundamental frequency range, rich harmonics, and complex waveforms. Traditional power meters cannot meet the test requirements of frequency conversion power. Under this circumstance, the power analyzer was developed to meet these requirements.

The power analyzer usually needs to adapt to the test needs of variable frequency power, and requires more functions and higher technical indicators.

Since there are many parameters to be measured, and some parameters need to be processed based on digital signals such as digital filters and Fourier transforms, power testers are mostly based on AC sampling technology, and various parameters that need to be measured are acquired by AC sampling. The digital sample sequence is obtained by correlation operation. For example, the true effective value can be obtained by performing root-mean-square operation on the digital sample sequence of one signal cycle of the measured voltage, and the Fourier transform can be used to obtain the fundamental wave effective value, harmonic amplitude and phase of the measured voltage, and further operation Harmonic distortion, harmonic content, and more can be obtained.

### Power Analyzers can operate at wider range of fundamental frequency

Traditional power meters are generally only suitable for 50Hz/60Hz power frequency electrical parameter measurement, and some power meters are specialized for 400Hz electrical parameter measurement.

The power analyzer generally requires a wider frequency band. As far as the fundamental frequency is concerned, the low frequency is generally 1Hz or lower, and the high frequency is 400Hz or higher.

### Power Analyzers have more functions

Traditional wattmeters mainly measure electrical parameters as voltage RMS, current RMS and active power. In addition to the above parameters, the power tester generally also requires the measurement of fundamental voltage RMS, fundamental current RMS, fundamental active power and harmonic voltage, harmonic current and harmonic power.

Since there are many parameters to be measured by power analyzer, and some parameters need to be processed based on digital signals such as digital filters and Fourier transforms, power anaylzers are mostly based on AC sampling technology, and various parameters that need to be measured are acquired by AC sampling. The digital sample sequence is obtained by correlation operation. For example, the true effective value can be obtained by performing root-mean-square operation on the digital sample sequence of one signal cycle of the measured voltage, and the Fourier transform can be used to obtain the fundamental wave effective value, harmonic amplitude and phase of the measured voltage, and further operation Harmonic distortion, harmonic content, and more can be obtained.

Power analyzer generally also includes the functions of a harmonic detector or a harmonic analyzer and a real-time oscilloscope.

### Power analyzers needs to work under Higher Bandwidth

The output waveform of the frequency converter is a PWM wave, and the fundamental frequency is not necessarily high. However, the PWM wave contains rich high-order harmonics. Therefore, the power analyzer generally requires a wider bandwidth.

Generally speaking, the frequency conversion motor test mainly focuses on the fundamental wave and low-order harmonics. According to the requirements of relevant national standards, generally 30kHz is sufficient.

The switching frequency of some low-power inverters is very high, and the power tester needs a higher bandwidth. Generally, the bandwidth is required to be at least 6 times the switching frequency.

For example, the switching of electronic ballasts for fluorescent lamps may be as high as 50kHz, and the bandwidth of the power tester is preferably above 300kHz.

### Power Analyzers have more functions

Traditional wattmeters mainly measure electrical parameters as voltage RMS, current RMS and active power. In addition to the above parameters, the power tester generally also requires the measurement of fundamental voltage RMS, fundamental current RMS, fundamental active power and harmonic voltage, harmonic current and harmonic power.

Since there are many parameters to be measured by power analyzer, and some parameters need to be processed based on digital signals such as digital filters and Fourier transforms, power anaylzers are mostly based on AC sampling technology, and various parameters that need to be measured are acquired by AC sampling. The digital sample sequence is obtained by correlation operation. For example, the true effective value can be obtained by performing root-mean-square operation on the digital sample sequence of one signal cycle of the measured voltage, and the Fourier transform can be used to obtain the fundamental wave effective value, harmonic amplitude and phase of the measured voltage, and further operation Harmonic distortion, harmonic content, and more can be obtained.

Power analyzer generally also includes the functions of a harmonic detector or a harmonic analyzer and a real-time oscilloscope.

### They support different types of sensors

When the amplitude of the measured electrical parameter is greater than the range of the power tester, it is necessary to add a voltage sensor and a current sensor at the input end of the power tester. Voltage sensors and current sensors also need to meet the relevant bandwidth requirements.

Compared with power testers, the bandwidth of sensors, especially voltage sensors, is the current technical bottleneck. At present, the voltage sensors suitable for frequency conversion power measurement mainly include the Hall voltage sensor, and its bandwidth is generally within 15kHz, the maximum test voltage is 6400V, and the bandwidth is only 700Hz.

The RAPS series variable frequency power sensor developed by RenAn Precision integrates voltage and current sensors. The voltage bandwidth can reach 100kHz, the current bandwidth can reach 30kHz, and the global accuracy can reach 0.05%.

### Power analyzers need to adapt to more complex electromagnetic environments

In the operating environment of the inverter, the electromagnetic environment is complex, and the electromagnetic compatibility of the power analyzer is one of the key indicators to determine whether the test results are credible.

In contrast, the traditional power meter faces a relatively simple electromagnetic environment with low electromagnetic interference, while the voltage transformer and current transformer supporting the power meter have a large output signal and strong anti-interference ability.

However, the voltage and current sensors suitable for frequency conversion power measurement not only have to face a more complex electromagnetic environment, but also have a small output signal and weak anti-interference ability.

When the anti-interference ability of the sensor is weakened, and the environmental interference becomes larger, which leads to the problem of electromagnetic compatibility becoming a key difficulty in the high-precision measurement of frequency conversion power.

The RAPS series frequency conversion power sensor developed by RenAn Precision. adopts the front-end digital technology based on optical fiber transmission. The optical fiber transmission not only has strong anti-interference ability, but also cuts off the important way of electromagnetic interference, which greatly improves the electromagnetic compatibility of the product.

To sum up, the power analyzer can be understood as an upgraded product of the traditional power meter. For traditional power frequency electricity, the two functions are equivalent, but the RAPA600 power analyzer has a wider range of application. It can usually meet the test requirements of various frequency conversion power.