A hybrid flyback LED driver with utility grid and renewable energy interface
In renewable energy sources, the objective is maximum extraction and utilization of the available power. In this paper a hybrid flyback converter with multi ports-an AC Grid, a PV and a DC LED ports — is proposed to be used as an LED driver. The converter has the capability to achieve two objectives: first to maintain a continuous supply to the LED lighting system either from the Photovoltaic (PV) panel or the grid, and second to achieve maximum utilization of the solar PV panel by tracking the maximum power point and exporting surplus power to the grid, or getting the power deficit from the grid. The topology of the converter, operating principle, modes of operation and control structure are presented in this work. The concept of the hybrid flyback converter is verified using Matlab Simulink®. An experimental prototype is developed and tested for a 120-watt system, with 35 VDC solar panels, 120 Vrms 60 Hz grid and 24 VDC LED lights.
Energy-Saving Led Lighting System With Parallel Power Supply By Photovoltaic Modules And By Network
The current state of LED lighting systems with parallel power supply by photovoltaic modules and central power supply network is analysed. The approach to implementation of parallel operation of LED luminaire powered by two sources of power is presented. It is simple, cheap and highly reliable as compared to the existing solutions. Based on this approach, four diagrams are developed which are applicable correspondingly to lighting applications and characteristics of photovoltaic modules and power consumers. The first and the second diagrams contain minimal quantity of transformers, but a number of operational constraints shall be taken into account when using them. The third diagram contains standard transformers and implies minimal number of various constraints, which makes it an optimal solution for the low-power lighting system being designed. The fourth diagram is expensive due to utilisation of equipment with automatic maximum power point tracking (the MPPT technology); it provides maximum possible energy efficiency of the lighting systems but the advantages of the MPPT technology apply only to high-power systems.
It is preferable to use such objects where lighting is mostly required during daytime as consumers of such systems (shopping malls, underground passages, storage facilities, poultry farms, etc.). A positive aspect is increase in reliability of consumer power supply since power supply of LED luminaires will be also provided by an additional source.
The proposed approach leads to reduction of power consumption for LED lighting, saving of fossil energy sources and therefore to ecologisation of the environment.
Fully Integrated Bidirectional CMOS-MEMS Flow Sensor With Low Power Pulse Operation
Leveraging More-than-Moore technology, we demonstrate an integrated CMOS MEMS flow sensor via a very compact system on chip (SoC) that can sense the bidirectional N2 gas flow. Our SoC features a very low-noise instrumentation amplifier that is implemented on a CMOS wafer and serves as a readout integrated circuit for a thermoresistive micro-calorimetric flow sensor which is fabricated on a MEMS wafer. A compact heterogeneous integration is achieved by combining the two wafers via the proprietary InvenSense AlN process. The measured sensitivity of our CMOS MEMS flow sensor is 98 mV/sccm which is three times better than the state-of-the-art counterpart. The flow range measured by our SoC is from −26 to 26 m/s (from −50 to 50 sccm). Moreover, the pulsed heater operation makes this proposed SoC flow sensor a very low power (<9 mW) and, thus, a promising candidate for the Internet-of-Things applications in smart home/green buildings.