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 eliminated.

In addition to its robust topology, key performance characteristics 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

For more details, read: Current-Fed Power Processing—Ride Through Robustness

Designed and Manufactured in the USA, Available Worldwide

For complete control of quality, MagnaDC programmable DC power supplies are designed and manufactured at Magna-Power's vertically integrated USA manufacturing facility in Flemington, New Jersey. Heat-sinks and chassis are machined from aluminum. All sheet metal is fabricated and powder coated in-house. Magnetics are wound-to-order from validated designs based on a model's voltage and current. An automated surface-mount production line places components on printed circuit boards for control, driver, auxiliary power, and display circuits. And finally after assembly, products undergo comprehensive test and calibration, followed by an extended burn-in period.

For more details: Tour Our Manufacturing Operations.

Standard Safety Features

MagnaDC programmable DC 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.

Included Software and Drivers

All MagnaDC programmable DC power supplies come standard with National Instruments LabVIEW and IVI drivers. In addition, the support SCPI command set provides an easy to use API using ASCII commands over any interface.

In addition to being able to develop your own software, Magna-Power's Remote Interface Software is also included with all power supplies. The software provides the user with an easy and intuitive method to operate a Magna-Power Electronics power supply with computer control. The Remote Interface Software has six different windows, including:

• Virtual Control Panel. Use a virtual front panel on the desktop to remote control the power supply from a computer.
• Command Panel. Explore all the available commands, along with logs of what string the software is sending to the power supply; used for developing your own software.
• Register Panel. Quickly get the status of all the power supply registers from one screen.
• Calibration Panel. Recalibrate internal digital potentiometers.
• Firmware Panel. Upgrade the power supply's firmware.
• Modulation Panel. Emulate non-linear profiles, such as solar arrays, pseudo-resistance for N+1 redundancy without wires, or automatic compensation for leadless remote sensing.

The included Remote Interface software supports RS232, LXI TCP/IP Ethernet, and IEEE-488, along with the USB and RS485 converters.

High Performance Master-Slave Operation

All MagnaDC programmable DC power supplies come with master-slaving capability.

The MagnaDC master-slaving strategy helps to ensures no degradation in performance as units are added in parallel or series by providing gate drive signals directly from the master to the slave units. This strategy ensures one control loop for the system and eliminates the noise susceptibility commonly found when sending analog control references over long distances.

The Universal Interface Device 47 (UID47) accessory eases master-slave parallel or series configuration of Magna-Power DC power supplies, enabling near equal current or voltage sharing, depending on the configuration.

Master-slave series operation is supported to combined voltages up to the product's DC Output Isolation specification. No external blocking diodes are requires for series operation.

External User I/O for Analog Control

Using the rear isolated 37-pin I/O connector, included as standard, the MagnaDC programmable power supplies can be completely controlled and monitored using external signals. The voltage, current, over voltage and over current set points are set by applying a 0-10V analog signal. Each diagnostic condition is given a designated pin, which reads +5V when high. Reference +5V and +10V signals are provided, eliminating the need for external voltage signals and allowing the use of dry contacts.

Also, the power supply features a normally closed external interlock, which when enabled, allows the power supply to be tied in with other emergency stop equipment. All these pins are isolated from the output terminals and referenced to earth-ground as standard—no additional isolation equipment or options necessary.

The following list summarizes the available I/O from the power supply:

• 4 analog inputs (0-10V)
• 2 analog outputs (0-10V)
• 5 digital inputs (5V)
• 15 digital outputs (5V)
• +2.5V, +5V and +10V reference signals

With the High Slew Rate Output (+HS) option equipped, high bandwidth operation is enabled along with fast rise times, allowing the MagnaDC programmable DC power supplies to address requirements for Hardware-in-the-Loop (HIL).

MT Series Harmonic Neutralization

Magna-Power's Harmonic Neutralizers eliminate families of harmonic components by multiplying the number of input phases with specially wound magnetic components, reducing the total harmonic distortion (THD). These magnetic components, in combination with equally loaded, high-power DC power supplies, offer a cost-effective solution to maintaining power quality at acceptable levels, enabling applications to benefit from Magna-Power's reliable high-frequency switch-mode power supplies, extended into multi-megawatts. A 12-pulse Harmonic Neutralizer is embedded in all 250 kW models and its installation is transparent to the end user. For applications demanding an even better THD level than that provided by a 12-pulse waveform, external 24-pulse and 48-pulse harmonic neutralizers are available from Magna-Power. Contact you local sales partner for more information.

Understanding AC Harmonic Waveforms

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.

Front Panel - Standard

Front Panel - C Version