Magna-Power

Integrated Blocking Diode

apitel — Thu, 09 Feb 2017 16:01:12 +0000

The Integrated Blocking Diode Option (+BD) provides an internally heat-sunk protection diode on the positive output terminal of a MagnaDC programmable DC power supply. This diode protects the product's output from reverse voltage up to 1200 Vdc. All voltage sensing is performed after the protection diode—at the product's output terminals—making the diode's operation completely transparent to the performance of the power supply.

The +BD option is recommended for applications where there is significant back-emf or the possibility of a DC output voltage that could exceed the power supply's output voltage rating, such as:

DC motor drives
Battery and capacitor charging
Large electromagnets

In these applications, the integrated blocking diode can be used to prevent back-emf from the energy stored in the load into the power supply's output. Furthermore, the integrated blocking diode will prevent the power supply's internal bleed resistance from discharging the energy storaged in the load when the power supply is off or in standby.

The +BD option is available for the TS Series, MS Series, and MT Series models with maximum output voltage rating from 125 Vdc to 1000 Vdc.

Availability	TS Series, MS Series, and MT Series Models rated for 125 Vdc to 1000 Vdc
Reverse Voltage Rating	1200 Vdc
Additional Losses	Up to 1.4%

+BD

MagnaDC

DC Power Cabling, Terminated

apitel — Wed, 07 Dec 2016 15:06:39 +0000

Utilizing Magna-Power's internal cable manufacturing operations, custom-made DC power cables are offered as an accessory. The following table identifies the various cables and voltage ratings that are offered:

Cable Gauge (AWG)	Voltage Rating (Vdc)	Per Cable Ampacity Rating (90°C)
10	15000	55
4	600	100
4	4000	100
1	600	160
1	4000	160
2/0	600	223
2/0	4000	223
4/0	600	310
4/0	4000	310

Use the following cable configuration guide and the table above to define the appropriate cable for your application and product:

CBL-[Feet]-[Cable Gauge]-[Voltage Rating]-[Termination 1]-[Termination 2]

For example: CBL-10-4/0-600-3/8-3/8; 10-feet, 4/0 cable rated for 600 Vdc terminated with 3/8" lugs on both ends.

Magna-Power Product Thread Dimensions

The following table identifies the threading used for the various configurations of Magna-Power's programmable DC power supply products.

MagnaDC Product Series	Product's Maximum Voltage Rating (Vdc)	DC Output Bus Thread Size (in)
SL Series	≤ 1000	Qty (1) 3/8-16 per bus
XR Series	≤ 1000	Qty (1) 3/8-16 per bus
XR Series	> 1000 Vdc and ≤ 2000 Vdc	Qty (1) 1/4-28 per bus
XR Series	> 2000 Vdc	83-1R Receptacle; contact Magna-Power for replacement cables
TS Series	≤ 1000	Qty (1) 3/8-16 per bus, models 5 kW to 15 kW Qty (2) 3/8-16 per bus, models 20 kW to 30 kW Qty (4) 3/8-16 per bus, models 45 kW
TS Series	> 1000 Vdc and ≤ 4000 Vdc; or +ISO option	Qty (1) 1/4-28 per bus, models 5 kW to 15 kW Qty (2) 1/4-28 per bus, models 20 kW to 30 kW Qty (4) 1/4-28 per bus, models 45 kW
MS Series	≤ 1000	Qty (4) 3/8-16 per bus
MS Series	> 1000 Vdc and ≤ 4000 Vdc; or +ISO option	Qty (1) 3/8-16 per bus
MT Series	≤ 1000	Qty (4) 3/8-16 per bus
MT Series	> 1000 Vdc and ≤ 4000 Vdc; or +ISO option	Qty (1) 3/8-16 per bus

The following table identifies the threading used for the various configurations of Magna-Power's MagnaLOAD DC electronic load products.

MagnaLOAD Product Series	Product's Maximum Voltage Rating (Vdc)	DC Output Bus Thread Size (in)
ALx Series	≤ 1000	Qty (1) 3/8-16 per bus
ARx Series	≤ 1000	Qty (1) 3/8-16 per bus, models 7.5 kW to 15 kW Qty (2) 3/8-16 per bus, models 22.5 kW to 30 kW Qty (3) 3/8-16 per bus, models 37.5 kW to 45 kW
WRx Series	≤ 1000	Qty (1) 3/8-16 per bus, models 15 kW to 30 kW Qty (2) 3/8-16 per bus, models 60 kW Qty (3) 3/8-16 per bus, models 90 kW Qty (4) 3/8-16 per bus, models 120 kW

CBL

MagnaDC

Solar Array Emulation at the National Renewable Energy Laboratory

apitel — Sun, 02 Nov 2014 18:41:23 +0000

I had the opportunity to travel with one of Magna-Power’s technicians for the commissioning of a massive 1,500,000 watt programmable power supply system at the Department of Energy’s National Renewable Energy Laboratory (NREL) in Golden, Colorado. NREL is the leading United States facility for renewable energy research and development. The Energy Systems Integration Facility (ESIF) at NREL, where the 1.5 MW Magna-Power system is located, provides a test-bed for a clean, renewable and intelligent US energy infrastructure.

Entrance to the Department of Energy's National Renewable Energy Laboratory in Golden, CO

The Magna-Power system at NREL is comprised of six MTD1000-250/480+HS+ISO+LXI power supplies, which can be configured for either master-slave series or parallel operation with Magna-Power’s UID47 interconnecting device. Each MTD1000-250/480+HS+ISO+LXI power supply module is capable of 0-1000 Vdc and 0-250 Adc, continuously. With the +ISO option, each unit has a DC output isolation rating of ± 4000 Vdc, allowing the modules to be configured up to 4000 Vdc in series. With six modules, a variety of series and parallel configurations can be achieve. Like all of Magna-Power’s products, this system can be used as a standard constant current, constant voltage power supply or PV emulator. As a PV emulator, this system is used for testing and evaluation of new technologies and commercial products.

I had a chance to sit down with Mariko Shirazi, an Electrical Engineer instrumental in the PV simulator selection process, to discuss more about ESIF’s activities and application of Magna-Power’s MT Series programmable DC power supply.

The Energy Systems Integration Facility at the National Renewable Energy Laboratory

Interview with Mariko Shirazi, Ph.D.

What is the mission of the National Renewable Energy Laboratory, and in particular, the Energy Systems Integration Facility (ESIF)?
The overall goal of this facility to test energy systems including electrical, thermal and fuel, and to provide a platform that integrates all these systems into a unified test bed.

How are programmable DC power supplies used in order to achieve this goal?
Programmable DC power supplies are used as photovoltaic (PV) simulators. One of the great attractions of ESIF is that we have the capability to test commercial and utility scale (i.e. 100 kW, 1 MW, etc.) PV inverters here. We have a 1 MW AC grid simulator that allows us to impose abnormal voltage and frequency conditions on to the PV inverter to see how it responds, which is not a common capability of a public testing facility. As a result, inverter manufacturers are interested in bringing their inverters here to test. In conjunction with the AC grid simulator connection, we also need DC PV simulation capability. Since we don’t have 1 MW PV arrays available, we need the ability to generate that input. And also, even if we had an array available, PV simulators are nice because they can produce repeatable results and are not dependent on ambient conditions.

Programmable DC power supplies which are bidirectional can also be used to simulate a battery bank. If we want to test a large UPS inverter or other battery connected inverter, we may not have a battery of that size on hand but could still test the inverter with a battery simulator.

When did NREL’s PV simulator system go online and begin testing inverters?
We had a readiness verification in April 2013 we began testing inverters in May 2013. From the PV simulation side, we started with 1 MW of Magna-Power.

What were some of the key selection factors when you were evaluating various types of power supplies and PV emulators at this scale?
Power and voltage ratings. Bandwidth. Cost. Isolation voltage rating. Bi-directionality. Modularity. External analog inputs and type (voltage/current vs. irradiance/temperature, each has its own advantages depending on application). Software sophistication. Number of emulated points on a PV curve. Interpolation between successive curves. How fast the PV simulator could update curves. Ability to simulate multi-diode/multi-hump curves.

What are some of the key features of the Photovoltaic Power Profile Emulation (PPPE) software that have simplified your testing?
We like the ability to either manually enter an array or enter an array by maximum power point, open-circuit voltage and short-circuit parameters. We have not yet used the provided detailed model, where you enter temperature and irradiance, but we definitely like the other two modes.

Multiple Magna-Power 250 kW MT Series power supplies at NREL used for solar array emulation.

What about your application demanded High Isolation (+ISO) option?
We want to run at ± 2000 Vdc, either floating or grounded, so there is definitely a possibility we could float above the standard configuration’s output isolation. We absolutely wanted the highest output isolation voltage available; this was also a deciding factor.

Greg [another Electrical Engineer at ESIF] says he wants to have the biggest Magna-Power PV simulator in the world.
[Laughs] How big is the biggest?

3 MW.
Wow! Ok…

Do you plan to leverage the analog-digital I/O for your own controller?
Yes, we already have. We used a real-time Opal-RT system using our own PV model for simulation. I was pretty surprised it worked as well as it did because we were only running a 5 kW inverter with this huge supply.

What integrated features in the Magna-Power system ensured safety in this application?
Definitely the emergency stop input [Interlock]—critical.

The Magna-Power system is built using 250 kW modules. Are you using this modularity at all for reconfiguration of the system?
Modularity was key because we may want to test one 1.5 MW inverter, three different 500 kW inverters, six 250 kW inverters. You can imagine because as Energy Systems Integration Facility, we want to test single source equipment, but also what is the effect of multiple source equipment on the platform.

Mariko Shirazi currently serves as the Lead REDB Engineer for the NREL’s Energy Systems Integration Facility (ESIF). The REDB (Research Electrical Distribution Bus) is the backbone of the ESIF’s electrical system testing infrastructure. In her role as Lead REDB Engineer, Mari is responsible for ensuring the continued relevance, performance, and safe operation of critical research electrical equipment connected to the REDB. On the Research side, Mari focuses on power electronics and microgrid controls development. Mari received a B.S. in Mechanical Engineering from the University of Alaska, Fairbanks, and a Masters and Ph.D. in Electrical Engineering from the University of Colorado at Boulder.

Vice President of Operations

Customer Study

Interview

2015-01-05

Magna-Power Electronics, Inc.

http://www.magna-power.com

What is slew rate and what are the available configurations?

apitel — Fri, 27 Jun 2014 19:14:40 +0000

Slew rate defines the maximum rate of change per unit time for either output voltage or output current. Magna-Power's limits on slew rate produce a non-linear rise time effect. Magna-Power's slew rate specifications characterize the power supply's rise-time in response to a programmed voltage or current change. Slew rate is distinct from the power supply's much faster transient response specification, which characterizes the power supply's response to a step load change.

Magna-Power offers two configurations of its MagnaDC programmable DC power supplies: standard output and High Slew Rate (+HS) output. The standard output stage MagnaDC power supplies has been designed to provide the lowest possible output ripple voltage within the constraints of available components, size, and cost. Part of the output stage consists of a bank of aluminum electrolytic capacitors which has the desired electrical properties to provide this function. While the presence of these components and the resulting performance are normally industry accepted, there are applications where lower output capacitance with faster rise and fall times are extremely desirable and higher ripple voltage is acceptable. To meet this need, a High Slew Rate (+HS) option is available which has an output stage consisting of low capacitance film and aluminum electrolytic capacitors. The High Slew Rate (+HS) option must be installed at the factory, preferably at time of order. Upgrades to the +HS option are available, requiring the unit to be shipped back to the factory for upgrade. Table 1 provides the available slew rate specifications for MagnaDC programmable DC power supplies, assuming a fully resisitive load.

Table 1. Available slew rates from MagnaDC programmable DC power supplies

	Standard Units	Units with +HS Option
Voltage Slew Rate	100 ms	4 ms
Current Slew Rate	100 ms	8 ms

The slew rate specifications apply to any transition in voltage or current. For example, the same slew rate would apply for a programmed transition from 0 to 50% load as from 0 to 100%. The rise time for voltage and current can be model using Equation 1:

`V(t) = V_0(1 - e^(-t/Τ))`

Equation 1

where `V(t)` is the voltage at a particular time, `V_0` is the commanded output voltage, `t` is time, and `T` is the first order time constant (Magna-Power's slew rate specification) in seconds.

To illustrate the slew rate specifications, a TSD600-24/208+HS power supply was connected to a fully resistive load and commanded to its full scale voltage and current: 600 Vdc and 24 Adc, respectively. The results of this experiment are shown in Figure 1. The blue trace is the current signal and the yellow trace is the voltage signal. The relative performance, about full scale voltage-current, will be consistent with the results shown in Figure 1 for models with the High Slew Rate (+HS) option.

Figure 1. Voltage and current rise time on model with High Slew Rate (+HS) option

The new voltage and current set points were issued to the power supply at -20 ms from the origin. To confirm that Equation 1 agrees with the experimental results, we can analyze the first major time division, which occurs 10 ms after the unit begins to ramp up voltage and current. At this first major time division, `V_0` is 600 Vdc, `t` is 0.01 s, and `T` is 0.004 s as this is a high slew rate unit. Equation 2 shows the evaluation of Equation 1, which evalutes to be consistent with the yellow trace at first major time division of Figure 1.

`V(t) = 600*(1 - e^(-0.01/0.004))`

Equation 2

`V(t) = 550.74` [Vdc]

MagnaDC

Hardware

1002

Water Cooling

apitel — Fri, 08 Nov 2013 21:38:13 +0000

Water cooling is available for Magna-Power power supplies for use in corrosive environments, such as electroplating applications or in densely packaged system cabinets, where heat removal by air cooling presents a problem.

Water cooling is accomplished with chill plates and an integrated central heat exchanger. The chill plates provides a thermal conduction path for heat sensitive components and the central heat exchanger removes heat from air internal to the enclosure. Water cooled TS Series models have enclosures without vent holes and are basically sealed the unit from the environment. An internal solenoid valve enables water flow when the chill plate reaches 60°C. Operation of the solenoid prevents internal condensation.

Each 15 kW module has a 1/4" NPT female inlet and outlet for water flow. For models greater than 15 kW, external plumbing interconnects power supply modules. A minimum of 2.50" is recommended behind the enclosure for this hardware and user connections. For systems requiring more than one power supply, plumbing connections must be paralleled; that is, water should not flow from one power supply into another.

Water Cooling Specifications
Water Cooling	25°C maximum inlet temperature 1.5 GPM minimum flow rate for 15 kW units 3.0 GPM minimum flow rate for 20 kW - 30 kW units 4.5 GPM minimum flow rate for 45 kW - 75 kW units 80 PSI maximum pressure 1/4” NPT female pipe size for 5 kW - 15 kW units 1/2” NPT female for 20 kW - 75 kW units.

+WC

Programmable DC Power Supply

USB Edgeport Converter (Accessory)

apitel — Fri, 08 Nov 2013 20:59:33 +0000

Edgeport USB-to-serial converters offer instant I/O expansion for peripheral device connectivity. An out-of-the-box (external) alternative to PCI cards, Edgeport makes it easy to add serial port to a PC, server or thin client in minutes – without opening the chassis, reconfiguring or rebooting the system.

The USB Edgeport device plugs directly into the back of the power supply, creating a seamless USB interface. Feature-rich design, reliability and unmatched operating system support make Edgeport USB-to-serial converters ideal for mission-critical enterprise applications. USB cable included.

USB

Programmable DC Power Supply

RS-422 or RS-485 Converter (Accessory)

apitel — Fri, 08 Nov 2013 19:12:46 +0000

The RS-232 to RS422 or RS-485 converter is an external industrial accessory to convert the power supply's standard RS-232.

Data is converted in both directions, RS-232 Transmit data is converted to balanced RS-422 or RS-485 Transmit, and Received RS-422/RS-485 signals are converted to RS-232. Unlike converters which require programming hardware handshaking signals to control RS-485 or RS-422 operation, the +RS485 option provides automatic control. In RS-485 mode, the RS-485 driver is enabled by circuitry which senses the RS-232 TD input.In half duplex RS-485 mode, the receiver is enabled when not transmitting. For full duplex operation, the receiver is set always enabled. In RS-422 mode, the transmitter and receiver are always enabled. The operating mode is set with 4 switches (Table 1). The +RS485 option is powered by the RS-232 signal lines whether they are set high or low. If not enough power is available from the port, or no handshaking lines are available, a DC jack is provided to connect a 12VDC supply. The DB9 female connector for RS-232 is wired as DCE (like a modem).

Selectable RS-485 2-wire half-duplex, or RS-485 4-wire full-duplex operation
Selectable RS-422 operation - Transmit & Receive always enabled
DB9 Female RS-232 Connection, Terminal Blocks for RS-422/RS-485
Port power or External 12V DC power (jack)
Automatic RS-485 Driver Control - works without special programming
Built-in bridging switches for 2-wire or 4-wire modes – no external jumpers

RS485

Programmable DC Power Supply

IEEE-488 GPIB Interface

apitel — Fri, 08 Nov 2013 15:23:57 +0000

The IEEE-488 interface, sometimes called the General Purpose Interface Bus (GPIB), is a general purpose digital interface system that can be used to transfer data between two or more devices. It is particularly well-suited for interconnecting computers and instruments. Some of its key features are:

Up to 15 devices may be connected to one bus
Total bus length may be up to 20 m and the distance between devices may be up to 2 m
Communication is digital and messages are sent one byte (8 bits) at a time
Message transactions are hardware handshaked
Data rates may be up to 1 Mbyte/sec

The IEEE-488 GPIB interface in integrated with the power supply's rear communication ports. The IEEE 488 interface offers full compatibility with Magna-Power provided drivers, software and SCPI command set.

+GPIB

All

High Slew Rate Output

apitel — Thu, 07 Nov 2013 23:02:42 +0000

The high slew rate option solves several limitations inherent in switching power supply design. Rapid voltage transitions require internal electronics to supply the energy to charge and discharge output capacitors. Peak currents internal to the power supply define slew rate; utilizing less capacitance enables voltage transitions in shorter time periods. Additionally, less capacitance reduces requirements for discharge demands during open circuit conditions.

The standard output stage Magna-Power Electronics power supplies has been designed to provide the lowest possible output ripple voltage within the constraints of available components, size, and cost. Part of the output stage consists of a bank of aluminum electrolytic capacitors which has the desired electrical properties to provide this function. These components require bleed resistors to discharge any voltage when the power supply has no load and is disabled. While the presence of these components and the resulting performance are normally industry accepted, there are applications where lower output capacitance and lower loss bleed resistors are extremely desirable and higher ripple voltage is acceptable. To meet this need, a high-slew rate option is available which has an output stage consisting of low capacitance film and aluminum electrolytic capacitors and lower loss bleed resistors. Applications for the high-slew rate option include battery charging, photovoltaic emulation, power waveform generation, and medium speed power pulsing. These applications all benefit from higher bandwidth and in many cases, can tolerate increased ripple voltage.

Key Applications

For battery charger applications, output capacitance and internal bleed resistors present themselves as a load to the connecting batteries. One common practice is to use a series diode to block reverse current flow with the sacrifice of increased cost and lower efficiency. The high slew rate option, with its lower output capacitance and lower loss bleed resistors, enables direct connection to batteries without series blocking diodes.

For photovoltaic emulation applications, higher bandwidth and lower output capacitance enable improved performance with higher speed, maximum power tracker algorithms. Maximum power tracker circuitry deviates the operating point of photovoltaic arrays to determine maximum power output. Slow responding emulation sources can present a problem when the speed of the algorithm exceeds that of the source. Furthermore, with lower output capacitance, changes in the operating point and transients, caused by shorting the solar inverter input, produce lower unwanted input currents.

The high-slew rate option enables the power supply to operate as a low frequency, power pulse generator. With the special capacitors selected for this option, it is possible to superimpose waveforms or produce a medium speed pulse on top of the dc output and expect normal capacitor life. It is important to note that the power supply output is single quadrant; that is, the output voltage or current cannot reverse.

Specifications

High Slew Rate Performance Specifications
Slew Rate	4 ms, output voltage change from 0 to 63% 8 ms, output current change from 0 to 63%
Bandwidth	60 Hz remote analog voltage programming 45 Hz remote analog current programming

High Slew Rate Output Capacitance and Ripple: Models 2 kW to 75 kW
Output Voltage Range (Vdc)	Output Capacitance (μF)	Output Ripple (Vrms)
5 8-10 16 20 32 40-80 100-250 375-400 500 600 800 1000 1500-2000 3000-4000	13200 9000 4080 2340 1050 300 200 160 100 60 40 26 18 9	0.5 0.5 0.5 0.7 1.4 1.5 1.6 1.8 2.1 2.3 2.5 3.0 3.5 4.0
Note: 1. For 20 to 30 kW models, multiply capacitance by 2 2. For 45 kW models, multiply capacitance by 3 3. For 60 kW models, multiply capacitance by 4 4. For 75 kW models, multiply capacitance by 5

High Slew Rate Output Capacitance and Ripple: Models 100 kW to 600 kW
Output Voltage Range (Vdc)	Output Capacitance (μF)	Output Ripple (Vrms)
16-20 32-80 100-160 200-250 375-400 500 600 800 1000 1250-2000 3000-4000	41000 16000 8000 3650 1280 960 640 480 320 160 80	0.5 1.4 1.6 1.7 1.8 2.1 2.3 2.5 3.0 3.5 4.0
Note: 1. For 200 kW and 300 kW models, multiply capacitance by 2 2. For 400 kW and 600 kW models, multiply capacitance by 4 3. For 450 kW models, multiply capacitance by 3

+HS

Programmable DC Power Supply

Universal Interface Device (Accessory)

apitel — Thu, 07 Nov 2013 22:51:59 +0000

Magna-Power Electronics UID47 is a general purpose device for connection to Magna-Power Electronics power supplies. The device contains the necessary circuitry for configuring power supplies for master-slave parallel or series operation.

Master/slave parallel operation allows two or more power supplies to equally share output current when connected together. Master/slave series operation allows two or more power supplies to equally share output voltage when connected together. In either operation mode, the master unit will command the slave units to the proper voltage and current. Each unit will display its own individual voltage and current. Installation requires setting jumpers, placing included 37-conductor cables between the UID47 and power supplies, and wiring the power supply outputs in either parallel or series.

The UID47 can be used as an interface for connecting control and monitoring lines to external circuitry. It also contains an area on the printed circuit board for interconnecting wires and placing components for specific user applications.

Key Features

Compatible with all Magna-Power Electronics power supplies
Interface for series and parallel master/slave operation
User configurable screw terminal connector
Pad area for custom circuitry
(2) 6-foot 37-pin cables included

Specifications
Connectors	JR1: 37 D-subminature, female JR2: 37 D-subminature, female JR3: 37 D-subminature, female JR4: 10 pin plug connector
Ambient Temperature	0°C to 50°C
Size (H" x W" x D") and Weight:	1.240 x 7.140 x 4.010 at 6.54 oz

UID47

Programmable DC Power Supply