New additional characteristic curves of Demke DC-Transformer, also available for customized dc-dc converters
New additional characteristic curves of Demke DC-Transformer, also available for customized dc-dc converters.
To make it easier to understand the special characteristics of our DC/DC converters, a characteristic curve plot will be available as take away (PDF) for each article in the future.
The respective operating modes can be represented visually much better.
Initially available are the characteristic curves of the output voltage in relation to the output current as well as the characteristic curve plots of the efficiencies on the one hand in relation to the output current and on the other hand in relation to the output voltage.
The characteristic curve plots are explained using the 257E-28-SD DC/DC converter. This device is an electrically non-isolated DC/DC buck and boost converter with an input voltage range of 15 to 35VDC and a charging end voltage of 28VDC with a maximum output current of 13A. Of course, the short-circuit current differs from the maximum output current, the maximum output current refers to the CV operating mode where the output power is not yet limited.
The output voltage as a function of the output current illustrates the CC-CV characteristic curve for different operating modes of the DC Transformer, for example in buck mode (lowering the DC output voltage) or in boost mode (raising the DC output voltage).
Figure 1: Behaviour of the output voltage versus the output current of the galvanically non-isolated DC/DC Buck-Boost converter 257E-28-SD at different input voltages.
The efficiency plot as a function of the output current illustrates the performance in voltage-controlled operation (CV mode).
Figure 2: Efficiency vs. output current (CV-mode) of the galvanically non-isolated DC/DC Buck-Boost converter 257E-28-SD at different input voltages.
The efficiency plot in relation to the output voltage illustrates the performance in current controlled operation (CC mode).
Figure 3: Efficiency vs. output voltage (CC-mode) of the galvanically non-isolated DC/DC Buck-Boost converter 257E-28-SD at different input voltages.
If one imagines the two efficiency plots continuously in the transition-gap from CV to CC, a detailed picture is received if the DC/DC converter is operated as a battery charging converter and the operating point must change continiously from CC to CV and vice versa.
In a next step, the ratio of input voltage to output voltage is presented. This characteristic curve will illustrate operating modes such as Buck-Boost better, whether isolated or non-isolated.
Demke DC transformers have always been optimised for maximum efficiency with minimum EMC interferences - this is just one of the goals we are consistently pursuing. Performance and closed loop control theory optimisations into the last detail also enjoy topmost priority.