Description: The aim of this work is to improve the energy, the mass and the dimensional characteristics of the launch systems of gas turbine engines for helicopters. To launch the GTE helicopter, a two-loop system with a subordinate current loop is proposed. The presence of a current loop makes it possible to perform current cutoff and smooth control of the rate of current (torque) rise in a DC-free DC motor. The presence in the system of a brushless DC motor instead of its collector X and a quasi-resonant pulse converter switched at zero current leads to a reduction in the mass and dimensions of the power electrical equipment on board the helicopter and to a reduction in electromagnetic interference. The current loop is tuned to the finite duration of the process, taking into account its uncompensated time constant, which is determined by the filter time constants set at the output of the regulator and the current sensor, and also taking into account the specific electromagnetic processes in the system in the quasi resonance pulsed converter – brushless DC motor .Synthesis of the speed loop controller is performed according to the speed criterion taking into account the optimization results of the current loop. Based on the discrete transfer function of the speed loop controller, a difference equation is obtained whose solution is realized by a recursive digital filter in accordance with the proposed structural scheme. It is shown that the software implementation of the solution of the difference equation is entrusted. The effect of the ratio between the compensated time constant of the current loop and the frequency of the clock control of the quasiresonance transducer control system on the rate of increase in the current (torque) of the brushless DC motor is established, which allows it to be smoothly adjusted during the launch of the helicopter engine. Such control is most effective if the ratio of the clock period to the uncompensated time constant of the current loop is within one to six. The results of the performed research are expedient for use in the development and modernization of helicopter power supply systems.
Keywords: Speed, switch, discrete transfer function, optimal controller, modified Z-conversion, quasi-resonant pulse converter, brushless DC motor, speed loop