Noise suppression method for an AM radio receiver using digital signal processing
Recently, electromagnetic interference in AM radio receivers associated with noise generated from the power control unit (DC-DC converters/inverters) and other power electronics devices, such as an electric power steering (EPS) control modules, in hybrid vehicles (HVs) has become a serious problem. In order to address this problem, most noise suppression methods use either noise filters (for noise sources) or shield wiring and ferrite cores (for noise propagation paths). We have proposed a noise suppression method through digital signal processing in an AM radio receiver. In this method, the received AM radio signal containing HV noise is first quadrature demodulated. Next, a replica signal of the noise is generated using the noise signal in the quadrature component. The replica signal is then subtracted from the AM radio signal containing the noise of the in-phase component. In this paper, first, we show the noise canceling method. And then, we construct a prototype of the radio receiver system based on the method. Finally, we demonstrate that the system can reduce the DC-DC converter noise and the EPS noise superimposed at the same time on the AM radio signal by more than 15 dB.
Common-mode noise source and its passive cancellation in full-bridge resonant converter
In this paper the results of systematic investigation into identification of dominant source of CM noise generation in a full bridge resonant converter are presented. It is shown that a small mismatch in an apparently symmetrical circuit can result in large CM injection. Mathematical analysis to predict the CM current injection is presented and is validated using SPICE simulation. For cancellation of dominant CM injection simple passive techniques are suggested. Experimental results on 18 kW LCC resonant magnet power supply for INDUS-2 are presented to demonstrate the effectiveness of proposed passive techniques.
Inverter noise suppression system using PI algorithm
This paper, proposes a novel noise reduction system composed of a noise sensor and an adaptive filter which is controlled based on PI(Power Inversion) algorithm. Numerical results show the noise reduction effects by the proposed system.