Abstract: A converter system includes a DC bus for each phase of an input AC power signal; a first switching cell for each phase, including first two active switches coupled in series across the DC bus and forming a first switching cell AC pole therebetween, the first switching cell AC pole being coupled to a respective phase; and a second switching cell for each phase, including second two active switches coupled in series across the DC bus and forming a second switching cell AC pole therebetween. The second switching cell AC poles are coupled to each other to form a flying neutral. One of the first switching cell and the second switching cell switches at a frequency at least an order of magnitude greater than the line frequency. The other of the first switching cell and the second switching cell switches at a frequency approximately equal to the line frequency.

Abstract: Systems, methods, techniques and apparatuses of short circuit protection are disclosed. One exemplary embodiment is a method for protecting a semiconductor switch comprising receiving a measurement corresponding to an electrical characteristic of the semiconductor switch; determining a semiconductor switch resistance value using the received measurement; estimating a junction temperature of the semiconductor switch using the semiconductor switch resistance value; determining a short circuit voltage threshold using the estimated junction temperature; comparing the short circuit voltage threshold to a test voltage corresponding to a drain-source voltage of the semiconductor switch; determining a short circuit condition is occurring in response to comparing the short circuit voltage threshold and the test voltage; and opening the semiconductor switch in response to determining the short circuit condition is occurring.

Abstract: Systems, methods, techniques and apparatuses of short circuit protection are disclosed. One exemplary embodiment is a method for protecting a semiconductor switch comprising receiving a measurement corresponding to an electrical characteristic of the semiconductor switch; determining a semiconductor switch resistance value using the received measurement; estimating a junction temperature of the semiconductor switch using the semiconductor switch resistance value; determining a short circuit voltage threshold using the estimated junction temperature; comparing the short circuit voltage threshold to a test voltage corresponding to a drain-source voltage of the semiconductor switch; determining a short circuit condition is occurring in response to comparing the short circuit voltage threshold and the test voltage; and opening the semiconductor switch in response to determining the short circuit condition is occurring.

Abstract: A converter system includes a DC bus for each phase of an input AC power signal; a first switching cell for each phase, including first two active switches coupled in series across the DC bus and forming a first switching cell AC pole therebetween, the first switching cell AC pole being coupled to a respective phase; and a second switching cell for each phase, including second two active switches coupled in series across the DC bus and forming a second switching cell AC pole therebetween. The second switching cell AC poles are coupled to each other to form a flying neutral. One of the first switching cell and the second switching cell switches at a frequency at least an order of magnitude greater than the line frequency. The other of the first switching cell and the second switching cell switches at a frequency approximately equal to the line frequency.