Feature Test & Measurement
he increased emphasis on energy efficiency, coupled with the expansion of new technologies in both power generation (wind, solar etc.) and conversion (high-fre- quency inverters, switch-mode power supplies etc.) has created a demand for new measuring instruments combining high accuracy with the versatility to handle multiple inputs. Areas as diverse as building controls, office automation and automotive electronics all present challenges with their combi- nation of DC and AC voltages of differ- ent levels and frequencies, and all require measurements of key parame- ters such as input/output voltages and currents, power flows and overall power consumption.
New measures for renewables T
Clive Davis, Product Marketing Manager at Yokogawa Europe explores some innovative measurement functions for precision power analysis
measure the power in the three phases of the input as well as the output. Many of today's power converters make use of switch-mode regulators in order to save energy, but generate interfer- ence because the switching circuitry cre- ates current and voltage waveforms, which are far from linear and incorporate high levels of harmonics.
The need to make multiple measure- ments in these applications has stimu- lated the development of a new generation of digital power analysers incorporating a number of innovative functions for electrical power and effi- ciency measurements in a range of industries from inverter and drive design to alternative energy systems. The new instrument can not only make up to six simultaneous power input measurements; it also offers a very wide power measurement range from standby levels up to high power systems (up to 1100 V and 55 A), a fre- quency bandwidth up to 5 MHz (-3 dB) with a sample rate of 2 MS/s, and power measurement simultaneously with two- line harmonic measurement at harmon- ics up to the 500th order.
The ability to make measurements on six inputs is particularly useful for test- ing high-frequency regulators, where it becomes possible to simultaneously
In order to measure these waveforms accurately, a 16-bit analogue-digital con- verter is used to sample the waveforms with a speed of 2 MS/s. As a result, meas- urements are taken over a bandwidth ranging from DC to 0.1 Hz to 1 MHz and a basic accuracy of 0.1% of the measured value plus 0.05% of the full scale. For the testing of applications associ- ated with electric motors, the new analyser has a built-in motor evaluation function. All motor parameters, includ- ing electrical power, rotational speed, moment of torque, mechanical power, synchronous speed, slip, motor effi- ciency and efficiency of the entire system can be visualised.
An alternative to the motor measure- ment option is the auxiliary input option. This provides two analogue inputs, which can be used to take the output from other measuring devices. The analyser is equipped with an extensive programmable digital filter.
Peak power analyser speeds T & M time
and wireless markets. The device integrates new N1923A and N1924A wideband power sensors, which cover a frequency range of 50 MHz to 18 GHz and 50 MHz to 40 GHz, respectively. When combined with either sensor, the analyser achieves 5 nanosecond rise time/fall time, which is claimed by the company to be the fastest overall rise time/fall time in the peak- power market, making the device an ideal solution for RF pulse measurement and analysis. The instrument is built for ease of use and high performance and is equipped with a 15-inch XGA colour touchscreen that is capable of simultaneously dis- playing four channel results for more image detail. With the 8990B’s sampling rate of 100 MSa/s, R&D engineers get the high resolution needed to detect abnormalities in a signal trace for design improvement. It also comes with 15 predefined pulse parameter measurements. Agilent Technology:
www.agilent.com
A Electronics JULY 2011
new peak power analyser that improves measurement-speed and offers greater measurement accuracy in peak power- pulse analysis has been released by Agilent Technologies Inc. The Agilent 8990B is aimed at the aerospace, defence
The new WT1800- next generation of digital power analysers from Yokogawa, incorporate
extended functions for electrical power and efficiency measurements
Components of interfering harmonics and noise from equipment such as fre- quency regulators can be filtered out with this. This filter can be incorpo- rated into each input and is independ- ent of other filter functions.
For signals with a frequency of 50 Hz, an analysis of the signal's har- monic behaviour can be carried out to the 500th order. This feature is espe- cially important in measurements on modern power electronics.
A double harmonics measurement function makes it possible to make har- monics simultaneously visible from two different sources. This means that the behaviour at both the input and the output of a frequency regulator, for exam- ple, can be made visible. At the same time, all normal power parameters and harmonic behaviour can also be analysed. This approach ultimately pro- vides a better picture of the performance of the device, which is being measured. The meter is equipped with a measur- ing function especially for applications with solar cells, with which the peak power can be followed in a correct manner. This provides an insight into the amount of energy generated by the instal- lation and if it is up to expectations. For solar-panel or wind-generator applications, the instrument is also able to measure how much energy has passed from the generator to the public network and how much energy is involved from the public network. In this way, insight can be gained as to whether the assessment of the energy consumption and the amount of energy sold is correct.
Enter 201
For situations where power con- sumption fluctuates strongly, the analyser is equipped with a trigger function, allowing measurement to be made according to preset conditions. To set the triggers, an area must first be set within which the normal situa- tion falls. The moment the measured value falls outside this area, the analyser is activated and measurement values are stored or printed. For engineers and end-users dealing with equipment as diverse as switch- mode power supplies, frequency driv- ers for energy efficiency, LED lamps, electric motors, or equipment associ- ated with energy generation from sun and wind or associated with, there is now a versatile measurement instru- ment that is fully equipped to measure the performance of these devices. Yokogawa Europe
www.tmi.yokogawa.com/ea Enter 200
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