Motor drive power analysis software upgrades oscilloscopes

With the addition of three-phase power analyser capability and motor speed and torque integration, the complete drive system can be more quickly and easily validated and debugged, and extensive drive and motor power and efficiency measurements may be performed.

The HDO8000 and Motor Drive Power Analyser software can be used by designers and manufacturers of motors, motor drives, variable frequency drives, variable speed drives, industrial automation and motion control equipment manufacturers.

Design engineers that integrate motors into their designs (vehicles, power tools, appliances, elevators, fans, blowers, compressors, pumps, etc.) will utilise the product to validate proprietary controls and complete drive system designs.

A complete drive system is a complex mix of three-phase power electronics, motor/mechanical analog and digital sensors, and embedded controls, with a complex variety of analogue, digital, serial data and pulse-width modulated (PWM) signals.

Oscilloscopes are able to capture higher-speed embedded control system or power transistor activities, but until now have been unable to measure drive power and efficiencies. Power Analysers are a single-use tool for measuring input/output “black-box” drive power and efficiencies, but provide limited or no waveform capture for embedded control or drive system debug.

The HDO8000 oscilloscope with Motor Drive Power Analyser software permits waveform captures from the drive power section, individual power transistors, and embedded control system, and performs coincident three-phase power analysis of the power section waveforms in one high-performance instrument, enabling debug and analysis of all aspects of the complete motor drive.

An intuitive, graphical user interface provides setup/connection guidance.

Setup capability is provided for any combination of single-phase or three-phase drive input/output, and supports both two- and three-wattmeter calculation methods and a line-line to line-neutral voltage conversion. Using the two-wattmeter method, drive input/output and motor output efficiencies can be measured using the eight inputs on the oscilloscope.

The Motor Drive Power Analyser software permits simple integration of nearly any type of speed, rotation or position sensor, including analogue and digital (pulse) tachometers, Brushless DC (BLDC) Hall sensor, Quadrature Encoder Interface (QEI), and Resolvers. Additionally, Hall sensor and QEI signals can be integrated through digital inputs, preserving valuable analog input channels for other signals.

Various voltage, current, power (real, apparent, and reactive), phase angle/power factor, and efficiency parameters are calculated on acquired voltage and current waveforms and displayed in a table. The table is user-configurable and is displayed along with the acquisition waveform, and corresponds to information normally provided by a Power Analyser.

Additionally, a waveform showing any per-cycle measurement parameter variation can be displayed by simply selecting a table value. This waveform is time-correlated with other waveforms acquired by the HDO8000 oscilloscope and can be used to correlate complex drive behaviors to other control or power system waveforms, and to debug drive system problems.

Statistical detail of the measurement set can also be displayed. This additional information goes well beyond what is provided by a Power Analyser.