A flow sensor includes a fluid chamber configured to receive a fluid. A diaphragm assembly is configured to be displaced whenever the fluid within the fluid chamber is displaced. A transducer assembly is configured to monitor the displacement of the diaphragm assembly and generate a signal based, at least in part, upon the quantity of fluid displaced within the fluid chamber.

Product dispensing system

The concept of injecting photovoltaic power into the utility grid has earned widespread acceptance in these days of renewable energy generation & distribution. Grid-connected inverters have evolved significantly with high diversity. Efficiency, size, weight, reliability etc. have all improved significantly with the development of modern and innovative inverter configurations and these factors have influenced the cost of producing inverters. In this review work, all aspects covering standards and specifications of single-phase grid-connected inverter, summary of inverter types, historical development of inverter technologies, classifications of inverter topologies are presented in a systematic manner. Finally, some transformer-less topologies based on bridge configuration and multilevel concept, and some soft-switching inverter topologies are remarked as desirable with respect to high efficiency, low cost, and compact structure. Areas of further works including use of advanced semiconductor devices, improvement of de-coupling capacitor etc. are also pointed out to draw attention of inverter designer for further increase of efficiency and lowering the cost.

A review of inverter topologies for single-phase grid-connected photovoltaic systems

This paper introduces a complete design method to construct an adaptive fuzzy logic controller (AFLC) for DC-DC converter. In a conventional fuzzy logic controller (FLC), knowledge on the system supplied by an expert is required for developing membership functions (parameters) and control rules. The proposed AFLC, on the other hand, do not required expert for making parameters and control rules. Instead, parameters and rules are generated using a model data file, which contains summary of input-output pairs. The FLC use Mamdani type fuzzy logic controllers for the defuzzification strategy and inference operators. The proposed controller is designed and verified by digital computer simulation and then implemented for buck, boost and buck-boost converters by using an 8-bit microcontroller.

Adaptive fuzzy logic controller for DC-DC converters

In this paper, a robust digital voltage-mode controller (DVMC) is proposed for a fifth-order boost point-of-load converter. Salient features of the proposed topology are compared with a conventional boost converter. Mathematical models are formulated using a discrete-time modeling technique and then employed in the compensator design, which uses the digital direct design approach. The DVMC is designed to ensure load voltage regulation. Robustness theory is applied directly in the digital domain, and then, various robust stability criteria describing sensitivity functions are formulated. The controller is designed to satisfy robustness criteria and then evaluated over a range of disturbances in spite of the fact that it maintains regulation. To confirm this, design simulations have been carried out on a 25-W 12-36-V converter system. Experimental results are provided to validate the concept and also to verify the range over which the designed controller is robust.

Robust Digital Voltage-Mode Controller for Fifth-Order Boost Converter

In this paper, a robust digital proportional-integral-derivative (PID) controller is proposed for the H-bridge soft-switching boost converter (HSBC). This digital PID controller is designed to ensure load voltage regulation as well as to give robust performance with step loads and source rejection. The mathematical models of the H-bridge boost converter are formulated, using the system identification tool, and then used in digital PID design. Here, this compensator is designed in the direct digital domain according to a pole placement approach that uses sensitivity function shaping in order to ensure closed-loop converter system stability as well as robust performance against converter parameter uncertainties. To confirm this, design simulations have been carried out on a 60-W 24-42-V HSBC. The experimental results are provided to validate the robust controller design concept.

Design of Robust Digital PID Controller for H-Bridge Soft-Switching Boost Converter

In many applications of DC-DC converters, loads cannot be specified in advance, i.e., their amplitudes are suddenly changed from the zero to the maximum rating. Generally, design conditions are changed for each load and then each controller is re-designed. Then, a so-called robust DC-DC converter which can cover such extensive load changes and also input voltage changes with one controller is needed. Analog control IC is used usually for the controller of DC-DC converter. Simple integral control etc. is performed with the analog control IC. However it is difficult to retain sufficient robustness of DC-DC converter by these techniques. The authors proposed the method of designing an approximate 2-degree-of-freedom (2DOF) controller of DC-AC converter. This controller has an ability to attain sufficient robustness against extensive load and DC power supply changes. For applying this approximate 2DOF controller to DC-DC converter, it is necessary to improve the degree of approximation for better robustness. In this paper, we propose a method of designing high-order approximate 2DOF digital controller which makes the control bandwidth wider, and at the same time makes a variation of the output voltage very small at a sudden change of resistive load. The proposed high-order approximate 2DOF digital controller is actually implemented on a DSP and is connected to a DC-DC converter. Experimental studies demonstrate that this type digital controller can satisfy given specifications.

Robust control of DC-DC converter by high-order approximate 2-degree-of-freedom digital controller

[PROBLEMS] A robust digital controller incorporating a novel two-freedom-degree robust digital control system which has a high degree of approximation and does not need to take account of the magnitude of the control inputs and a designing device for the same are provided. [MEANS FOR SOLVING PROBLEMS] Control compensating means (70A) determines, as a higher-approximation second-order approximated model transfer function Wm (z), a discrete transfer function Wry (z) between a target value r and a controlled variable y, and is configured according to the model transfer function Wm (z) as an integral control system in which computation is carried out in a digital controller (70). A designing device automatically calculates parameters constituting the control system. With this, compared to conventional approximated digital control systems realizing first-order approximation model, a digital controller (70) which has a high degree of approximation and is strong to output noise can be easily realized.

Robust digital controller and its designing device

Robust DC-DC converter which can cover extensive load changes and also input voltage changes with one controller is needed. Then the demand to suppressing output voltage change becomes still severer. We proposed an aproximate 2DOF digital controller which realizes the startup response and dynamic load response independently. The controller makes the control bandwidth wider, and at the same time makes a variation of the output voltage small at sudden changes of loads and the input voltages. In this paper, a new approximate 2DOF digital control system with additional zeros is proposed. Using additional zeros a second- order differential transfer characteristics between equivalent disturbances and an output voltage is realized. So the new controller makes a variation of the output voltage more small at sudden changes of loads and the input voltages. This controller is actually implemented on a DSP and is connected to a DC-DC converter. Experimental studies demonstrate that this type of digital controller can satisfy given severe specifications.

Digital Robust Control for DC-DC Converter with Second-Order Differential Characteristics

In order to increase the conversion efficiency of grid-connected PV-systems, a high-efficiency PV power inverter with simple control methodology is required. To satisfy this requirement, an improved single-phase inverter using soft-switching technique is proposed. The proposed power inverter circuit is composed of a ZVT-PWM boost dc-dc converter and a LLCC resonant inverter. The dc-link voltage amplitude is controlled by ZVT-PWM boost dc-dc converter with soft-switching transition for all active switches. The stable sinusoid ac output voltage is inverted from dc-link voltage via a LLCC resonant inverter. The effectiveness of the proposed grid-connected inverter for small PV system is verified by simulation results.

An improved soft-switching single-phase inverter for small grid-connected PV-system

The moisture content inspection for agriculture material is very necessary to make a quality control. Since the amount of the soybean meal, which can transmute into animal food, is very plenty and the distribution of moisture is difference. Therefore, the non-destructive moisture inspection is difficult to perform. This paper proposes microwave free-space measurement using the resonance cavity. Measuring the resonance frequency after passing the soybean meal and calculate them in term of complex permittivity. The results show that the technique can provide fast soybean meal moisture classification with 80% of accuracy.

http://ieeexplore.ieee.org/iel5/5305883/5332438/05333037.pdf

K. Higuchi

Papers

Robust control of DC-DC converter by high-order approximate 2-degree-of-freedom digital controller

Robust digital controller and its designing device

Digital Robust Control for DC-DC Converter with Second-Order Differential Characteristics

An improved soft-switching single-phase inverter for small grid-connected PV-system

Microwave-based soybean meal moisture classification using resonance cavity