Mixed control method for direct current (DC)-direct current (DC) convertor

Abstract

The invention discloses a mixed control method for a direct current (DC)-direct current (DC) convertor. The method comprises the following steps: building a mixed automaton model of the DC-DC convertor; limiting the ripple magnitude of inductor current in the DC-DC convertor so as to select a switching frequency f in the mixed control method; calculating boundary condition of a mixed control algorithm according to the expected values of input voltage, load resistance and output voltage of a main circuit of the DC-DC convertor, and judging which mode the DC-DC convertor works in, namely, an inductor current continuous mode or an inductor current discontinuous mode; outputting by a digital signal processor (DSP) the control signal indicating whether a switching tube of the main circuit is conducted or not according to the comparative result of state variable and the boundary condition, so as to drive the main circuit to work. The mixed control method simplifies a control problem to a boundary selection problem, so that the algorithm is simple, and further, the DC-DC convertor can simultaneously work in a continuous conduction mode (CCM) and a direct current mode (DCM) with a constant frequency, therefore, the DC-DC convertor has the characteristics of high dynamic response speed and high steady accuracy.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a hybrid control method of a DC-DC converter suitable for both CCM and DCM modes. Background technique [0002] DC-DC converters are widely used in portable devices. Switching converters are favored by people because of their high efficiency, flexible positive and negative polarity, and buck-boost mode. DC-DC converter mainly adopts PWM (Pulse Width Modulation) technology, which is a kind of strongly nonlinear system. On the one hand, the different states of the main switch in the DC-DC converter make the DC-DC converter work in different topologies; on the other hand, there are two operating modes of the DC-DC converter: inductor current continuous mode (CCM) or Inductor Current Discontinuous Mode (DCM). In the design of the traditional control strategy, it is necessary to model the two working modes separately. First, it causes the complexity of the cont...

AI Technical Summary

Problems solved by technology

In the design of traditional control strategies, it is necessary to model the two operating modes separately. First, it causes the complexity of the control strategy design of the DC-DC converter. Second, the DC-DC converter cannot work in two operating modes at the same time (CCM or DCM), that is, it is difficult to work stably in a wide range of load changes

Images