MT Series (100KW up)

MT Series.pdf

Fully Programmable DC Power

The MT Series features programmable voltage, current, and protection settings along with high accuracy measurements. The SL Series functions and features are accessible and configurable from a variety of control methods, including:

• Front panel interface with stepless knobs
• 37-pin isolated analog-digital user I/O
• RS232 Computer interface with software and drivers

Various additional programming interfaces are available, such as LXI TCP/IP Ethernet (+LXI), IEEE-488 GPIB (+GPIB), Edgeport USB Accessory (+USB), RS485 Accessory (+RS485).

Designed for Safety

MT Series power supplies have extensive diagnostic functions, including:

• AC Phase Loss
• Excessive Thermal Conditions
• Over Voltage Trip (Programmable)
• Over Current Trip (Programmable)
• Cleared Fuse
• Excessive Program Line Voltage
• Interlock Fault

When in standby or diagnostic fault, the AC mains are mechanically disconnected by an embedded AC contactor, providing confidence that the unit is only processing power when desired.

Finally, with a dedicated +5V interlock input pin and included +5V reference on all models, external emergency stop systems can be easily integrated using an external contact.

Extensive Programming Support

All MT Series MagnaDC power supplies come with a dedicated National Instruments LabVIEW™ driver, Interchangeable Virtual Instrument (IVI) driver, and support for a wide range of Standard Commands for Programmable Instrumentation (SCPI). These programming interfaces support full control, measurement, and monitoring of the MagnaLOAD. All of the MagnaLOAD's available communication interfaces are supported by these drivers and command sets, including: RS232, LXI TCP/IP Ethernet, IEEE-488 GPIB, USB or RS485.

Showcased in the following basic code examples, SCPI commands provide the simplest form of communication by using plain ASCII text and parameters sent over a basic socket connection. Over 50 commands are provided, with detailed documentation in the MT Series User Manual.

Finally, Magna-Power's RIS Panel software is provided allowing for a virtual control panel controlling the power supply via any of the available communication interfaces


Current-Fed Topology: Robust Power Conversion

All MagnaDC programmable DC power supplies utilize high-frequency IGBT-based power processing in current-fed topology. This topology adds an additional stage over the conventional voltage-fed topology for enhanced control and system protection, ensuring that even under a fault condition, the power supply will self-protect. Due to the self-protecting characteristics of this topology, the possibility of fast rising current spikes and magnetic core saturation is elimated.

In addition to its robust topology, key performance characterics of MagnaDC programmable DC power supplies include:

• High-accuracy voltage and current programming accuracy
• Class-leading line and load regulation performance
• High 3Φ AC input power factor with in-rush limiting circuitry
• Computer and user I/O isolated from the power supply output

The following figures are representative of expected AC current waveforms for the various pulses available from Magna-Power Electronics power supplies. Standard models 1.5 kW through 150 kW produce 6-pulse waveforms, while 250 kW models produce 12-pulse waveforms. Magna-Power Electronics Harmonic Neutralizers suppress families of harmonics by increasing the number of power phases. It can be used when multiple power supplies are used in series or parallel and are equally loaded. Harmonic Neutralizers can produce 12-pulse, 18-pulse, 24-pulse, or 48-pulse waveforms which have harmonic current components on the order of 12n±1, 18n±1, 24n±1, or 48n±1, respectively. The following figures show the theoretical difference for waveforms with a different number of pulses. Harmonic Neutralizers are protected with appropriate sized primary-side circuit breakers.

Why Neutralize Harmonics?

Input current harmonics are a by-product of nearly all power supplies. Power can only be delivered to the load if the frequency and phase of the voltage and current match. For a three phase power supply using a three phase input rectifier, the input current has a theoretical spectrum of 6n±1 where n is an integer incrementing from 1; this is known as a 6-pulse waveform. This means that a power supply with a three phase input rectifier will produce input currents at 1, 5, 7, 11, 13, 17, 19 ... times the fundamental frequency. The theoretical magnitude decays as the reciprocal of the harmonic component. The 5th and 7th harmonic components have magnitudes of 20% and 14% of the fundamental component, respectively. Harmonics currents in power systems can find unusual paths and can cause problems if the magnitude is significant and there are loads sensitive to harmonic frequencies. For example, lighting ballasts have series connected capacitors and inductors which can be excited by harmonic currents. IEEE has introduced standard, IEEE 519, which defines recommended limits. Implementing this standard requires a knowledge of the power system and other loads producing harmonics. Unfortunately, the standard can allow the same power supply to possibly exceed limits in one application and not in another. In the same respect, a power supply may or may not can cause a harmonic related problem with or without meeting IEEE 519. The best solution to minimize the risk of a harmonic problem is to eliminate the harmonic current at the source.