Input current control of boost converters using current-mode controller integrated with linear quadratic regulator

The application of power electronic converter in the renewable energy systems significantly increases their efficiencies by maintaining the operation of these systems at the optimal operating points, therefore, absorbing the maximum available power from the renewable sources all the time. In this paper, the small-signal models of the open-loop, current-mode controlled boost converter are derived. In addition, both the Current Mode Control (CMC) and the Linear Quadratic Regulator (LQR) methods are combined to design a controller that forces the input current of the converter to follow accurately a reference current, which could be generated using maximum power point tracking (MPPT) algorithms. The controller performance is tested under transient conditions and with disturbance signals using MATLAB/Simulink simulation package. The simulation results indicate that both a good response and disturbance rejection are achieved in tested conditions

Using Nyquist or Nyquist-Like Plot to Predict Three Typical Instabilities in DC-DC Converters

By transforming an exact stability condition, a new Nyquist-like plot is proposed to predict occurrences of three typical instabilities in DC-DC converters. The three instabilities are saddle-node bifurcation (coexistence of multiple solutions), period-doubling bifurcation (subharmonic oscillation), and Neimark bifurcation (quasi-periodic oscillation). In a single plot, it accurately predicts whether an instability occurs and what type the instability is. The plot is equivalent to the Nyquist plot, and it is a useful design tool to avoid these instabilities. Nine examples are used to illustrate the accuracy of this new plot to predict instabilities in the buck or boost converter with fixed or variable switching frequency.Comment: Submitted to an IEEE journal in 201

On δ-Small Pseudo Projective Modules

In this paper we give three new concepts, a concepts of δ-Small pseudo projective module, δ-small quasi projective and δ-small pseudo stable module, these concepts are generalization of Pseudo Projective modules, quasi projective module and pseudo stable module respectively we will study these concepts and give some results

Small-signal modeling of current-mode controlled modular DC-DC converters using the state-space algebraic approach

Small-signal models are useful tools to preliminary understand the dynamics of interconnected systems like modular dc-dc converters which find a wide range of industrial applications. This work proposes a state-space-based averaged small-signal model in symbolic form for a peak current-mode controlled parallel-input/parallel-output buck converter operating in the continuous-conduction mode. In modeling the converter power-stage each module is independently represented. For modeling the current-mode control the state-space algebraic approach is used to incorporate the current-mode control-law into the power-stage equations. For each module two parasitic elements in addition to the current-loop sampling action are included in the derivation. Furthermore, the control-to-output voltage transfer functions are presented in symbolic form for two cases of interest: the first when the converter has two non-identical modules to study the effect of inductor mismatch, and the second when the converter is composed of n-connected identical modules to assess the effect of varying the number of modules. All responses from PSIM cycle-by-cycle simulations are in good agreement with the mathematical model predictions up to half the switching frequency

Investigation of the relationship between age and weight with Postoperative Myalgia Following Succinylcholine Administration: a cross sectional

One of the issues that is thought to occur frequently following surgery that uses succinylcholine as part of the anaesthesia protocol is post-operative myalgia. The patient may experience a somewhat unsatisfactory outcome following surgery as a result of this complication. In the meantime, studies on the incidence and avoidance of post-operative myalgia following succinylcholine administration were conducted. There was a dearth of information and research on this topic in Iraq. Our study\u27s goal is to investigate the connection between weight and age and postoperative myalgia after succinylcholine administration.In the months of September and October of 2022, a sample of patients from two hospitals in the city of Karbala was collected. After collecting data on myalgia scores 6-, 12-, and 24-hours following surgery, the data was analysed, and the significant value was determined to be p<0.05. In our population, female patients made up the largest percentage (approximately 65.5%), while male patients made up only 34.5% of the sample. Less than 1% of patients reported being pain-free six hours after the procedure, whereas almost all patients had myalgia. The percentage of patients who had mild myalgia was 47.4%, or about half. Furthermore, moderate pain was reported by 43.3% of them. Just 8.2% of patients reported being in excruciating pain. Age and muscle pain have an inverse relationship, according to all time interval pain assessment (P<0.05). We found no evidence of a significant relationship between the patient\u27s weight category increasing and muscle pain after six, twelve, or twenty-four hours.Lastly, we have determined that post-operative myalgia caused by succinylcholine is common in the Iraqi population and affects most patients across a range of age groups. Generally speaking, the severity of muscle pain decreases with age. Neither the patient\u27s weight nor the amount of succinylcholine had an impact on the outcome of myalgia.