CALCULATION OF INDUCTANCE FOR A BI-DIRECTIONAL DC/DC CONVERTER IN AUTONOMOUS UNDERWATER APPARATUS

Submersible apparatus work at a depth inaccessible for divers and submarines. They are small devices linked with the depot ship due to their limited autonomous capacity. Application of submersible apparatus helps to enlarge the range of their operation and to decrease maintenance costs. Accumulator storage batteries with relatively low voltage are the main power source of these apparatus. DC converter operation is influenced by the inductance value. The article deals with the problems of calculating the inductance for bi-directional DC voltage converters for autonomous underwater apparatus. The scheme of the converter is presented, its operation modes are considered, equations describing the processes in the electrical circuit for different states of the IGBT-transistor are compiled. An expression describing the current oscillations in the regime of continuous current with certain assumptions is derived. It is stated that the inductance should be greater than a certain value to ensure the operation of the DC converter in the continuous current mode. Dependences of the current ripple through the inductor are plotted as a function of the inductance. Simulation of the DC converter made in the Simulink package is performed and oscillograms of the current and voltage at the output of the converter are shown, which confirm the correctness of the procedure for determining the minimum value of the inductance to ensure operation of the DC converter in the continuous current mode.

Improved Research on the Transformer-Inductor Simulation Model of Magnetics

Transformer-inductor simulation model not only reflects the characteristics of magnetic path and circuit, but also brings in magnetic components that reflected the parasitic capacitance. There are further research, strict derivation and magnetic circuit equivalent for the model in this article. Under the condition of considering hysteresis, saturation effect we can conclude a new modeling and its equivalent, which can make the magnetic curve and characteristic get better fitting. It shows that the transformer-inductance simulation model is easy to spread and use.