Power electronic building blocks
Paul Smallbon · The University of Queensland · 1999
The paper focuses on the design, testing, and construction of three power electronic building blocks. They are a zero crossing detector, a voltage isolation module, and a current isolation module. Each of the modules run on a unipolar supply of 5Vdc and can accept high voltages and currents. The zero crossing detector can accept a 240Vac at 50Hz mains power supply as its input and output a TTL signal accurate to 15ms. The voltage isolation module has two switches associated with the circuit. The first switch lets the user choose between a x 100 probe or a x 200 probe that reduces the input voltage by a factor of 100 or 200. The second switch allows the output voltage to be referenced to either 0V or 2.5Vdc. The x 100 probe is generally used for DC voltage inputs with a reference voltage of 0V. This module proved to be very accurate over a range of 4Vdc to 60Vdc. Although the paper shows that the module is capable of handling voltages exceeding 400Vdc. The x 200 probe is generally used for 240Vac mains power input and is used with a reference voltage of 2.5Vdc to obtain both positive and negative peaks of the input wave. It is very accurate over a voltage range of 12Vac to 240Vac. The module returns a common-mode rejection ratio of 47dB, a 3-dB point of 600kHz, and a gain-bandwidth product of 1MHz. The current isolation module can accept AC and DC currents over a range from 0A to 20A. The module contains a switch that allows the user to switch between three current settings; 5A, 10A, and 20A depending on the magnitude of the input current. This module is accurate over the range of 0A to 2A.