Design, implementation, and control of driver with increasing frequency for linear induction launchers

Electromagnetic launchers use electromagnetic force instead of the force produced by chemical energy for launching a projectile, unlike traditional launchers. The current passing through the barrel creates a magnetic field around it. This creates a short circuit current on the projectile. A force is induced on the projectile carrying current within the magnetic field. The projectile is pushed and launched out of the magnetic field due to the influence of this force. Electromagnetic launchers are studied under two main categories: rail launchers and coil launchers. Among coil launchers, linear induction type launchers are attracting more attention from researchers in recent years. Linear Induction Launchers (LILs) have an air core that does not contain ferromagnetic material. As LILs are a special type of linear induction motors, they have all the advantages of linear induction motors, such as high-power density, low maintenance needs, and durability. In the proposed thesis, a Linear Induction Launcher was produced to launch a 100 g aluminum cylindrical projectile. The AC (Alternating Current) voltage of the 3-phase network was rectified to meet the energy requirements of the launcher and transmitted to a DC (Direct Current) bus consisting of film capacitor groups with high charge capacity and fast discharge performance. The DC voltage that formed on the capacitors was converted to AC voltage by an inverter. The design of a controller that would provide energy at gradually increasing frequencies to allow the projectile to gradually accelerate and prevent it from overheating at high frequencies was made. Space Vector Pulse Width Modulation (SVPWM) and open loop Variable Voltage Variable Frequency (VVVF) were chosen as the control method. The TMS320F28335 Digital Signal Processor (DSP) was used as the hardware element to perform the control. At the inverter input, a Cockroft-Walton (CW) type voltage multiplier has been used to generate higher DC voltage to be able to increase the voltage and frequency on the launcher. Launch tests have been carried out. Using current and frequency values obtained from the experiments, some simulations in Ansys Electronics/Maxwell 3D and Icepak were performed to study muzzle velocity and temperatures. The experimental and simulation test results demonstrate that LILs can be effectively driven with a 3-phase traditional converter setup and muzzle velocities at constant frequencies can be achieved with lower projectile temperatures using the increasing frequency energization method. Consequently, techniques for increasing the projectile velocity while decreasing temperature rise have been contributed to the literature.