Abstract
Switching power converters are widely used in order to provide output voltage stabilization of direct current off-line supply sources. There is huge set of DC-DC pulse converters, particularly, Cuk converters are frequently used. The distinctive feature of Cuk converters is the low level of high frequency noise which is generated by converter due to its switching operation. However, transient performance insides are imposed upon the output voltage and its satisfaction highly depends on effectiveness of applied control algorithms. Control system design for voltage converters is studied in plenty of works, but the discussed results are only numerical simulations. Therefore was decided to implement a testbed for performing experiments, which results can be compared with simulated ones. It is based on Cuk scheme with following elements values: power conductors L1= 0.456 mH and L2 = 0.317 mH, capacitors С1 = С1 =

= 0.470 mF, power switch – MOSFET IRF3808PBF, power diode – STTH2003CG. As control system is used digital one, realized on microcontroller (MC) STM32F107. Discussed testbed has a sampling rate as 30 kHz, uses 3 ADC channels (the first one for receiving data from current sensor, the second – from sensor of voltage on buffer capacitor, the third – from output voltage sensor). Sensing element of input current, realized on special ship ASC712, is used for measurement of current though input conductor (L1). Voltage sensors are constructed based on various connection layouts of operational amplifier (chip LM358) and intended for measurement of voltage on buffer capacitor (С1) and converter output. Special driver provides signal conditioning between power switch and MC. During a setup a connection between personal computer (PC) and MC is required. USART was chosen as communication interface. Testbed reliability is ensured by electrical isolation realized on certain circuit board (it contains two chips with required electrical elements. Chip ADUM provides electrical isolation and chip FTDI is USB-UART adapter). Presented functional scheme shows the mutual interactions between main components. Schematic circuit and its description are also presented. In order to debug microcontroller part of the testbed and control algorithms, monitor current system state special program is used.

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