Design of the control circuit used in variable speed diesel generator set
The advanced circuit design of boost and inverter has created much interest in generator of variable speed diesel generating sets. The boost circuit and the topological structure of the three-phase half-bridge inverter were analyzed. The control strategy of Sinusoidal PWM (SPWM) was implemented. To reduce the noise in the control feedback, a low pass filter was in used. At the end of this paper, the authors performed a series of experiments to confirm the stability of the generator set. The experiment results verified that the boost circuit and the inverter designed in this paper are reasonable and can satisfy all the requirements of the diesel generator set.
Variable speed genset with full rated power converter using readily available industrial products
Although a classic diesel genset may reach 35% efficiency at nominal load, it has very poor efficiency at low load conditions. Still, these conditions often occur in real world applications when combining gensets with variable autonomous loads. Previously, the authors built a hybrid genset prototype achieving fuel consumption reductions of over 30%. As an alternative to this hybrid genset, this paper reports on a variable speed genset prototype. To demonstrate a higher fuel efficiency, a prototype 50 kVA variable speed genset has been built using readily available industrial products. A diesel internal combustion engine supplies power to a PM synchronous generator to produce variable voltage, variable frequency AC. Using a four-quadrant variable-frequency drive and transformer this electrical energy is converted to produce an autonomous 4-wire 50 Hz 3×400 V grid. Operation principle, prototype implementation, first load tests (speed response and power quality) and possible improvements are discussed in this paper.
An intelligent control system for ventilators.
This study reports on a ventilator system that consists of several intelligent modules for controlling ventilator operation. These modules are software programs in two controllers. One controller is a personal computer used for diagnoses, determining settings and checking the effects of settings. The other controller is a single-chip microprocessor in a ventilator that controls the ventilator's settings in accordance with the computer settings. After setting up the system, an artificial lung model simulating a patient's lung is used to test the system. The result of test run indicated that it always responds to a patient's lung condition in a stable manner. Thus, the proposed system with its intelligent modules may assist clinicians in caring for patients and managing ventilator operation.