Flexible powers for all applications thanks to the intelligent overall concept
The electronic loads of the company EA Elektro-Automatik can be coupled by means of a few individual power modules to form a device or a cabinet system of up to 72 kW. In this way, the new EL 9000 B series covers a large part of applications. In addition, the power electronics manufacturer has solved problems that are normally common in electronic loads, such as vibrations or high-frequency input voltages.
When checking electronic components for function, power and parameters, it is usually done by electronic loads. While the test is being carried out, voltage, current, resistance and power can be individually adjusted and regulated. Since electronic loads are used in testing applications as variable as power supply, batteries or combustion modules, the challenge is to conceptualize them in such a way that they can be used in many variable ways. The company EA Elektro-Automatik GmbH & Co. KG from Viersen has recognized this need and has developed a new series of electronic loads that has a choice of voltage, current and power levels for various applications: the EL 9000 B series. It offers powers from 300W to 72kW, voltages from 80V to 750V and currents up to 5.100A.
individually adjustable stems
The extraordinary thing about this series is its modularity: thanks to this system of modules, compact power pieces can be coupled to form different devices: power pieces with 600W, 1.200W and 2.400W can be joined in one device up to a power of 14.400 W. In systems with a power of up to 72 kW, a main device and secondary devices are joined to form a unit in a cabinet. The complete system thus formed has the same ease of use and scope of function as a single device. The advantage of the modular system is obvious – on the one hand a large number of applications can be covered and on the other hand they can be easily and quickly adapted to new or additional requirements.
Interfaces: integrated and expandable
In order to control and check the devices, they have a communication unit that serves as a central link between the human-machine interface (HMI), the power section and the outside: as standard, an analogue interface as well as a USB interface are integrated on the back. of the apparatus. All interfaces are galvanically isolated at the output. The analog interface has in addition to the control inputs for U, I, P and R also mounting outputs for U and I. These inputs and outputs can be parameterized between 0 to 10 V and between 0 to 5 V. By means of a plug & play slot can be retrofitted with further digital interfaces for Ethernet, Modbus, TCP and Profinet as well as for Profibus, CANopen, CAN and RS232.
FPGA-based parallel signal processing
The regulation and digital control used in the electronic loads of the EL 9000 B series are based on the 16 Bit AD/DA transducer principle. Due to the parallel processing of the signal in the FPGA (Field Programmable Gate Array), a signal passing time – measure, calculate and set – of less than 1 μs is achieved. Therefore with a bandwidth of 1 MHz current, voltage, power and resistance measurements can be processed at the same time. The freely assignable look-up tables (LUTs) connected to the controller also work with a bandwidth of 1 MHz. In this way, complex non-linear resistance characteristics can also be reproduced – for example from LED chains or converters. PV. The desired table values can be created in CSV or text format and loaded into the lookup tables via USB interface.
New standard: The one with extended functions
The functionalities of the new EL 9000 B series far exceed those of conventional electronic loads: a special feature is the FPGA-based digital random and function generator that enables the control of freely programmable and temporary load profiles. With this you can generate a multitude of curves such as sinus, triangle or rectangle. In addition there is a sequence and record function to consult and save the data. A battery management system makes it possible to test different batteries. Additional constants are freely configurable. This includes limit values for voltage, current, power and resistance as well as time parameters.
User guide: intuitive and conventional
To make operation easier for the user, EA Elektro-Automatik has developed a new user-friendly approach: Thanks to the high-resolution TFT touchscreen, the devices are operated intuitively. With a few touches, parameters can be chosen and values entered either via buttons or alphanumerically via a number pad. The large color display shows all target and actual values at the same time and in an orderly manner. In addition, the menu can be programmed in four languages – apart from German also in English, Chinese and Russian – using symbols of the country flags. To protect the human-machine interface (HMI) from unauthorized or unintentional use, it can be partially or completely blocked. The DC input is connected and disconnected by means of a key with tactile confirmation. In addition two LEDs show the status of the input.
Active isolation, reduced capacities
With the new modular series EA Elektro-Automatik additionally eliminates defects that occur in the application of conventional electronic loads: these include control vibrations, voltage mismatches or high-frequency input voltages. Regulation vibrations can occur when the power supply or other circuits are tested with their own regulation circuit. Physically this is possible if a phase misalignment of the regulating circuits of more than 180º occurs as well as a magnification greater than 1. Then the overall system oscillates. Long and rich induction lines can result in a distorted current rise. The new loads of the EL 9000 B series, on the contrary, ensure high current stability since they have an active electronic isolation of the DC input circuit. In this way the capacity of the DC input filter is minimized and the current source is protected: this is important since a high capacity at the DC input of a load can lead to unwanted current peaks that can damage the connected source. In order to avoid a possible overload of the input filter in a DC voltage with a high frequency AC part, it has its own protection.
DC input: protection by insulation
In the checks, voltage mismatches of the input of an electronic load versus PE can also occur, which pose a danger to the electronics and the user. If a load is tested that is not potentially disconnected from the grid, a dangerous grid potential exists at the input of the load. If the input is not disconnected from the housing and from all control elements, this entails great risks. That is why the loads of the EL 9000 B series from the input circuit to the housing, all control elements and the analog and digital interfaces are made highly insulated. This double insulation ensures a permitted floating voltage of +/- 400Veff. Therefore all devices connected to the interfaces are protected against high voltages and against mains potential. The user is also protected from high voltages when touching the control elements.
Smart heat management protects from test interruption
An important aspect is also protection against excessive heating. If the modules of the device exceed a certain temperature, the input will be disconnected in the usual loads. Both the disconnection and the temperature delta resulting from the disconnection temperature and the connection temperature cause the load to be unable to support power for a certain period of time. This leads to complex system tests having to be frequently interrupted. To prevent this, intelligent heat management has been integrated into the new loads of the EL 9000 B series. The semiconductor temperatures are constantly monitored. Above a certain temperature, the fans are first set to their maximum speed and then the output power is reduced. cargo input. A regulator circuit maintains the semiconductor temperatures at a level and thereby prevents excessive heating. In this way an immediate disconnection of the load input is avoided.
General concept: versatile, flexible and safe
With the general concept of a modular structure, the company EA Elektro-Automatik has developed electronic loads that are so versatile and flexible that they are suitable for almost all applications. The EL 9000 B series meets all requirements for safe electronic loads: individually combinable powers, good connectivity, many functionalities as well as high operating comfort.
