In part one of choosing a programmable power supply we discussed voltage, current, cooling and power requirements for your application. Here, we explore some of the more subtle aspects of the specification. We discuss parameters such as accuracy and repeatability, the different between ripple and noise and show how power supplies can be connected in series or parallel to increase the maximum voltage or current whilst delivering the same technical performance.
Accuracy, stability & repeatability
Accuracy of display is how close to the voltage and current display reflect the actual voltage and current being supplied. Typically, these range from 0.001% through to 1% of full scale. Note that the analogue read-back accuracy won’t be the same as the display or RS-232 because different circuitry is used to present the value. e.g. LCD readouts will be limited by the number of digits it can display.
Accuracy of set point is the difference between the “demand”, to what is actually delivered. Again, these range from 0.001% to 1%. Power supplies that offer multiple programming interfaces, will specify different accuracy figures for each interface.
Stability is often quoted as the short-term drift of output voltage and current. A stable output will resist changes in ambient or internal temperatures and other aging effects over time e.g. stability over 8hrs = <0.5%.
Repeatability is the degree to which a user can leave one set point, perhaps due to a power cycling event, and achieve the same output values at a later point in time. The built-in monitoring of programmable power supplies makes this relatively easy to check.
PLECS – specialists in simulation software for power electronics – have released version 3.7 of their Blockset and Standalone products.
The updated products now feature:
- Improved Thermal Modelling
Semiconductor losses can now be described using functional expressions in addition to lookup tables. It is also possible to define custom parameters (such as gate resistance) and describe their influence on the device losses.
Manufactured by Dean Technology, the new HVM40B high voltage voltmeter can be relied upon for highly accurate measurement of positive or negative voltages up to 40,000 volts.
PPM Power has added two new Dean Technology discrete diodes – the UX-F30B and CL03-30 – to its comprehensive range. The new axial lead diodes have a peak inverse voltage rating of 30kV and are higher voltage additions to the existing UX and CL03 series.
ABB’s high power IGBT ‘HiPak module’ semiconductors have recently been revised to incorporate a number of benefits. These include:
- Improved reliability
- Enhanced processes
- Better package design.
View product. Continue reading
The TDK Lambda Genesys series of 10kW and 15kW programmable DC power supplies is now available with output voltages of 800V, 1000V, 1250V and 1500V. These new models have the same dimensions as the existing 7.5V to 600V models – 19” wide and 3U high. The units can operate in either constant current or constant voltage modes and accept either three-phase 400V AC or 440V AC inputs.
The correct capacitor will reduce system failures therefore minimising costs and downtime. Here we review film capacitors versus electrolytics and ceramics and outline the benefits of film capacitors from different vendors.
PPM partner, Dean Technology has released a new product catalogue for power electronics which complements the high current and suppression product lines from their CKE division. Continue reading
Our new web tool automatically identifies matching IGBTs or diodes for your particular application, based on the conditions you enter. This will save you time and money doing long calculations or researching several different datasheets because you can find your IGBT or diode much quicker.
Posted in Seminconductors
Advanced modelling and simulation of power electronic systems
Register now for our next PLECS workshop: Wednesday, 27th January 2016 – 9am-4pm
The PLECS product family has been specifically developed to assist engineers with the design and implementation of complex power electronics systems.
We will guide you through exercises such as: modelling a switched-mode power supply, solver accuracy and settings, thermal modelling of a buck converter and creating a custom PV string component.