In this paper we develop a globally stabilizing stability-based switching controller for a three-state lumped parameter centrifugal compressor surge model. The proposed model involves pressure and mass flow compression system dynamics as well as spool dynamics to account for the influence of speed transients on the compression surge dynamics. The proposed nonlinear switching controller architec...

This paper presents FPGA-based implementation and performance analysis of the hardware for lossless compression of a floating-point data stream. The implementation includes the variable-to-fixed length converter (VFCONV) and the fixed-to-variable length converter (FVCONV) that have not been designed and evaluated so far. The prototype system on ALTERA Stratix IV FPGA demonstrates that the compr...

An optimisation procedure for twin screw compressor design is described, which is based on an analytical algorithm for rotor profile generation combined with a differential model of the fluid flow and thermodynamic processes within the machine. Rotor profiles are generated from a rack which have both stronger female rotor lobes and higher displacement. Compressors thus designed have higher deli...

In this article a low power and low latency 4-2 compressor has been presented. By using modified truth table and Pass Transistor Logic (PTL) a novel structure has been proposed which outperforms previous designs from the frequency of operation view point. The proposed design method has reduced the total transistor count considerably which will lead to reduced power consumption and smaller activ...

We derive a JPEG compliant image compressor which is based on hierarchical vector quantization (HVQ). The goal is to reduce complexity while increasing compression speed. For each block, the DCT DC coefficient is encoded in the regular way while the residual is mapped through HVQ to a pre-computed bit-stream corresponding to the compressed DCT AC coefficients. Approximation quality is generally...

This paper refers to the noise reduction of the rolling piston type rotary compressor. In general. as the rolling piston increases its speed under the high compression ratio condition. the noise level increases steeply. We resume that this happens because a certain shock wave is produced in the comPression space. Then we could simulate the Phenomenon by the numerical analysis ( CACE method ) of...

Vapor compression heat pump is an important aerospace thermal control means to lunar probe program and deep space exploration. Compressors are the most important component in vapor compression heat pump systems. Microgravity environment has a great impact on system performance. The paper tests the gravity independence of compressor performance, and evaluates the performance of compressor and he...

A pulse width modulation (PWM) bypass capacity control technique for air conditioners has been developed to achieve high scroll compressor efficiency over a wide capacity range, and we investigated the technique’s fundamental characteristics in this study. With this capacity control technique, the refrigerant flow rate is controlled by periodically switching a full load mode, in which the refri...