CONTROLLER OF NEUTRAL-POINT CLAMPING TYPE POWER CONVERTER

摘要

PURPOSE: To extend the application range of a power converter, by securing the minimum ON/OFF time for switching elements through varying the carrier frequency of a PWM control by a functional computation when the voltage command value of the power converter oversteps range of setting level, and by generating the output voltage of the power converter, which is proportional to the voltage command value. ;CONSTITUTION: A load current I_u is sensed by a CT_u, and is compared wit a current command value I_u* by a comparator C_u to obtain a deviation value ε_u, and the ε_u is amplified by a current control compensation circuit G_u (S) to obtain a voltage command value e_u. The voltage command value e_u is inputted to a PWM control circuit PWMC to be compared respectively by comparators C₁, C₂ with triangular wave signals X, Y generated from a triangular wave generator TRG, and the outputs of the comparators C₁, C₂ are inputted respectively to gate circuits GC₁, GC₂ via Schmitt circuits SM₁, SM₂ to create signals g₁, g₂. On the other hand, the voltage command value e_u is inputted to a functional computing unit FX₁ too to input a computed output value e_o to the triangular wave generator TRG via a voltage/frequency converter V/F, and thereby, the triangular wave signal X, Y having such a carrier frequency that ensumes the minimum ON/OFF time for self-arc-extinguishing elements S₁-S₄ are generated respectively from the generator TRG.;COPYRIGHT: (C)1994,JPO&Japio