-A transformerless converter suitable for multiphase drive application is presented in this paper. The topology employs a cascaded H-bridge rectifier as the interface between the grid and multi inverters which drive the multiphase motor. Compared with the conventional structure, the new topology eliminates the input transformer and also has the advantages such as four quadrant operation, simple configuration, low cost, high efficiency, and so on. The control strategies for the grid-side cascade H-bridge rectifier and the motorside inverter are studied accordingly. Based on the multi-rotational reference frame, modular control scheme is developed to regulate the multiphase drive system. Simulation results show the proper operation of the proposed topology and the corresponding control strategy.

A novel demodulation scheme with Sage-Husa adaptive Kalman filtering algorithm is presented for the digital readout system of a micro-machined gyroscope. Based on the analysis of the detection signal from gyroscope, a mathematical model of the detection signal is established in the condition of the additive white Gaussian noise, and the state and observation model for the demodulation scheme are also given. Moreover, the simulation system is built by the Matlab/Simulink. Assuming the input signal of angular velocity is the step or sine function, and the statistical characteristics of the noise in the detection signal are unknown, simulations are given to demodulate the detection signal with different SNRs (signal-to-noise ratio). In addition, the phase sensitive demodulation scheme in the analog readout system is simulated for comparison. Results show that, the demodulation gains reach +24.23dB (input SNR is above −12.04dB) and +23.92dB (input SNR is above −16.99dB) respectively when the angular velocity input is Ω = 0.005[deg/s] for the step function, while Ω = 0.005 sin(2π × 50t)[deg/ s] for the sine function. Meanwhile, the demodulation gain increases along with the decreasing SNR of the detection signal. Compared with the analog phase sensitive demodulation scheme, the demodulation output with Sage-Husa adaptive Kalman algorithm has the shorter convergence time, but about 5dB higher of MSE (mean square error). In conclusion, the novel demodulation scheme with Sage-Husa adaptive Kalman filtering algorithm can real-timely and precisely estimate the covariance of dynamic noise in the detection signal from gyroscope, and increase the SNR of the demodulation signals dramatically. It can demodulate the angular velocity accurately and quickly, and shows a good practicability.