3-Phase Power Analysis

The 4 Series MSO is available with up to 6 analog channels, making it well-suited for 3-phase power measurements. This three-phase analysis option (4-3PHASE) enables the 4 Series MSO to set up and perform the calculations needed to make key 3-phase power system measurements such as total power, harmonic distortion and phase parameters. The analysis package is ideal for design validation with flexible measurement trending and automatic reporting. Power converters often use Pulse Width Modulation (PWM) which complicates measurements since it is difficult to lock onto cycles. The analysis option includes filtering that provides stable measurements on PWM waveforms, while still providing the signal detail of a fast-sampling oscilloscope. Support for DC to three-phase AC converters make this package ideal for use in analyzing electric vehicle systems. Measurements are controlled using the 4 Series MSO’s intuitive touch interface. 12-bit ADC’s (up to 16- bit resolution in High Res mode) deliver accurate measurements and the three-phase power analysis software helps make measurements easier and repeatable.

Key features and specifications

Measurement overview

The three-phase analysis on the 4 Series MSO automates key electrical measurements which are grouped into the Electrical Analysis group. The measurements can be configured to measure the Input or Output wiring configuration.

The measurements can be set to measure 1V1I (1-Phase-2-Wire), 2V2I (1-Phase-3-Wire), 2V2I (3-Phase-3-Wire), 1V1I (1-Phase-2-Wire DC), 3V3I (3-Phase-3-Wire), and 3V3I (3-Phase-4-Wire) to support various wiring configurations. Measurements can be performed line-to-line or line-to-neutral, to support delta or wye (star) configurations.

Harmonics

Power waveforms are rarely textbook sinusoids. Harmonics measurements break down non-sinusoidal voltage or current waveforms into their sinusoidal components, indicating the frequency and amplitude for each component.

Harmonics analysis can be performed up to the 200^th harmonic order. The maximum harmonic order can be set to suit your needs by specifying the range in the measurement configuration. The THD-F, THD-R, and fundamental values are measured for each phase. Measurements can be evaluated against the IEEE-519, IEC 61000 3-2 standard, or custom limits. Test results are recorded in a detailed report, indicating pass/fail status.

The harmonics plot shows the test results for all three phases grouped so one can easily compare results among phases. For quick insight, harmonics bars are highlighted in green during a pass condition, and turn red when limits are exceeded.

Power quality

This measurement provides critical three-phase power measurements including

It also displays the sum of true power, the sum of reactive power, and the sum of apparent power components.

In addition, in the Line-Neutral configuration, this measurement displays True power, Reactive power, and Apparent power components of all three-phases. Voltage and current vectors are displayed on a phasor diagram so you can quickly judge the phase shift for each phase and the balance among phases. Each vector is represented by an RMS value and the phase is computed using the Discrete Fourier Transform (DFT) method.

Efficiency

Efficiency measures the ratio of the output power to input power (DC-in AC-out, 2V2I configuration, and 1V1I industrial configuration). The efficiency measurement leverages all 6-channels of the 4 Series MSO and computes the overall system efficiency (1 voltage and 1 current source on the input side, and 2 voltage and 2 current sources on the output side).

Ripple analysis

Ripple is residual or unwanted AC voltage on a DC power supply. In a three-phase converter system, it is typically measured on the DC bus. This measurement helps to understand how efficiently the signal is getting converted from AC-DC on the input side, and the impact of unwanted components on the PWM signal on the output side.

Dynamic measurements using Trend analysis

A common requirement in three-phase analysis is the need to look at the system response over longer test times to monitor the DUT behavior over varying load conditions. Trends provide insight into interdependency between different parameters like voltage, current, power, frequency, and their variance based on the load conditions.

Three-phase solution offers two unique trend plots on the power quality measurement to support such requirements – TimeTrend and Acq Trend plots. Each plot has its advantages and can be used to plot any of the power quality measurements. The Time Trend plot shows the measured value per cycle, or for an acquired waveform (a record), while the Acq Trend plot shows a mean of the measured value per record, over multiple acquisitions. The acquisition count is set by the user during the test configuration. This allows users to capture long records of data to perform deep record analysis and understand the dynamic behavior of the system response. The plots can be saved as a CSV file for offline analysis.

Report generation

The three-phase software simplifies data collection, archiving, documentation of your design, and development process. It supports the report generation in MHT or PDF formats with pass/fail results for easy analysis.