Short description WG5Kxxx Modular DC-converter system General characteristics The modular DC converter system is useful for the DC coupling of various electrical components (sources, sinks, storages) with different ranges of operating voltages ( 0...350V DC, 230V AC ). The coupling is carried out by voltage conversion and "normalization" to a joint voltage of DC. A bidirectional exchange of electrical energy can then be realized between the connected components by means of the DC link arising that way.. Fig. 1 Basic structure of the converter system Hardware components The DC converter system is based on the converter modules (DC/DC, DC/AC) and module carriers developed and produced by FLEXIVA. Every module carrier can be equipped with a maximum of 4 DC/DC or DC/AC modules. There are any combinations of the DC/DC and DC/AC module variants possible. The following variants of modules and module carriers are available: Type Order-No. Power variable Voltage Current Characteristics bidirectional galvanic isolation parallel connection others DC/DC ZEMIS PM3K030 2,5kW 0 30V DC -100... 0 100A yes yes yes DC/DC ZEMIS PM3K045 2,5kW 0 45V DC -75... 0 75A yes yes yes DC/DC ZEMIS PM3K060 2,5kW 0 60V DC -50... 0 50A yes yes yes DC/DC ZEMIS PM3K120 2,5kW 0 120V DC -25... 0 25A yes yes yes DC/DC ZEMIS PM3K350 3,5kW 0 DC -10 0 10A yes no yes DC/AC ZEMIS PM3AC10 2,3kW 230V AC 10A / 16 A for 30s yes no yes mains / off-grid operation possible Tab. 1 Types of modules 1
Type Order-No. Characteristics MT V2 ZEMIS WG5K020 max. 4 modules, 1 RS232 interface for all modules Tab. 2 Types of module carriers It is possible to use the DC/DC modules both as a single module and as coupled modules. Because of the galvanic isolation, both the connection in series and in parallel of the modules is possible to increase the power and/or the voltage at the side of the DC link. Fig. 2 Variants of connection in parallel or series Characteristics of module housing: - Mechanical fixing of all modules existing in the system, - Linkage of the DC link voltages of all modules to the DC link, - Distribution of the necessary external auxiliary voltage (12..30V DC) to all modules, - Control / operation management for simple applications realizable without external control (precondition: appropriate parameterization of the modules), - Data exchange by means of simple ASCII instructions (protocol disclosed), - Comfortable PC software for the parameterization included in the scope of delivery. The module housings of the converter system (19-inch plug-in units) can also be coupled to create larger-sized units. In case of a great number and diversity of the connected components, the usage of a high-performance external control unit for the control / system management is recommended (e.g. ZEMIS-WG5OP03 from Flexiva). Utilization and typical applications Basically the modular converter system is a very flexible hardware platform with no special focus of application. With the integration of the DC/AC-module in system solutions it is possible to realize the connection to the mains or to create independent local grids. Typical fields of utilization the system components are: - Coupling of renewable and other sources with local consumers of energy or the mains (µ-grids) - Integration of electrical storages into hybrid energy systems - Energetic integration of e-mobiles into stationary energy supply systems - Testing and analyzing of mobile concepts for drives, board-energy solutions and other energetic problems in the filed of e-mobility - Integration of hydrogen components like fuel cells and electrolysers into stationary energy concepts - Voltage adaption, power supply, local DC-grids, testing and verification of storage components in industrial equipments and laboratories 2
Energy Flow Control Energy Management The basic energy management consists in the task to take care that there is always enough electrical energy available in the DC link. This leads to the consequence that any inflows of electrical energy into the DC link and/or outflows of electrical energy from the DC link have to be regulated in a variable way in order to keep the available electrical energy always at a certain level. For this purpose, the voltage of the DC link serves as an indicator for the available energy. The task of controlling the inflows and outflows of electrical energy from and to the DC link is assumed by the DC/DC and/or DC/AC modules of the system that are installed between the connected component and the DC link. Every module gets a specific desired voltage specification for the DC link. Furthermore, it is instructed to take care that the intermediate DC link voltage reaches this certain value and keeps it. Independent of the other modules, every module now tries to fulfil its task by influencing the quantity and direction of the current flowing through itself. The parameterization includes mainly specifications for currents and voltages of the DC link and the component side as well as the mode of operation in which the module has to work. All further details of handling the system are described in the user manuals of the components. Depending on the system variant and its installed modules (with energy sources, sinks, and buffer stores), the control of the energy flow is possible both with and without higher-level control. The precondition is in both cases the well-aimed parameterization of the mode of operation, current and voltage values of all modules used according to the components connected to them and the energy flow strategies to be realized. Terminals To operate the module carrier, an auxiliary power supply must be connected to the terminal "24V". It powers the internal interface switcher as well as the built-in converter modules (depending on the configuration of the whole system). RS 232 Data communication with PC Bits per Second 115200 Data bits 8 Parity None Stop bits 1 Flow control None 24V Input auxiliary voltage, 12 to 30V DC, max. 50W Fuse 4AT Fuse for auxiliary voltage, 4A slow PE PE - terminal DC Link Connection of DC-link voltage 3
Further module and system features Dimension und weight - Module carrier 19 3U, approx. 430mm x 420mm x 135mm, approx. 5.9kg - DC/DC-Module (30/45/60/120V), approx. 230mm x 85mm x 105mm, approx. 1.9kg - DC/DC-Module (350V), approx. 270mm x 85mm x 105mm, approx. 2.2kg - DC/AC-Modul, approx. 270mm x 85mm x105mm, approx. 2.9kg - Further details in datasheets Minimal voltages of modules @ operating with rated current - The voltage range is between 0.2V and 6.0V, depending on type of module and direction of energy flow - Example: The module ZEMIS-PM3K030 has following minimal voltages o 0.2V @ -100A (current from DC-link into connected component) o 1.5V @ 100A (current from connected component into the DC-link) - The minimal voltages per type are termed in the user manuals. Current-/voltage rise per time - The rising of current or voltage per time depends on the chosen module parameters - @ setting the current, the maximum is arrived in 0.2 2 ms Accuracy of internal measurement - Measurement of voltage <1% - Measurement of current <3% (with additional external measurement and software offset the accuracy depends on the resolution of the desired parameter) Stability of default value - The medium drift of adjusted values for current and voltage (from start to the thermal stationary state) is approx. 1% of rated current and 0.2% of rated voltage Ripple - The current ripple of the DC/DC-modules is 0.5 1.0% (peak-peak) of the rated current (depending on setting the parameters). Efficiency - The efficiency of the modules depends on the operational point and the relation between actual to rated current of the module. - The following diagrams describe this relation. With help of these diagrams it s possible to calculate the efficiency in different operational points. 140 Power losses step up Verlustleistungen Hochsetzbetrieb 120 100 Pv (W) 80 60 60V-HS 30V-HS Polynomisch (30V-HS) Polynomisch (60V-HS) 40 20 Power losses Verlustleistungen step Tiefsetzbetrieb down 0 0 0,2 0,4 0,6 0,8 1 1,2 I/Imax 120 100 80 Pv (W) 60 60V-TS-32V 30V-TS-20V Polynomisch (30V-TS-20V) Polynomisch (60V-TS-32V) 40 Additional documents: Datasheets, user manuals 20 0 0 0,2 0,4 0,6 0,8 1 1,2 I/Imax 4
Appendix 1 Service, monitoring, external powermanagement serial interface ZEMIS WG5K020 Modular energy management of components optional system expansion DC-link serial DC-link DC serial DC-link DC 0-45V 0-60V 0-60V ~ 230V 0-350V 0-350V 0-120V 0-60V KWK FC H2 EL LAST PV Solar units wind generator accustorage ultracap storage other CHP- components fuel cell hydrogen storage elektrolyzer load / grid 230V AC 0...350V DC Features of ZEMIS Energy kit: Components of hybrid energy systems (examples) - modular configurable converter system, typical power per module 2.5 kw - dynamic and bidirectional control of energy flow for each connected component - large ranges of operating voltages to couple different components (0...350V DC) - parallel connection of the modules is possible for scaling the power range (2.5 5.0 7.5kW) - comfortable software to configure the system and the modules of it - open serial software interface for operation with simple ASCII-commands - possibility of direct external energy management via LAN/RS232-adaptor (optional) 1
Appendix 2 Modular converter-system for charging / discharging of electrical storages 2