Design and Performance Analysis of PID Controller for Extended Output Voltage Buck-Boost Converter

Buck-boost DC–DC converters are useful as DC grid interfaces for renewable energy resources. In the classical buck-boost converter, output voltages smaller than the input voltage (the buck region) are observed for duty cycles between 0 and 0.5. Several recent buck-boost converters have been designed to present higher voltage gains. Nevertheless, those topologies show a reduced duty-cycle range, leading to output voltages in the buck region, and thus require the use of very low duty cycles to achieve the lower range of buck output voltages. In this work, we propose a new buck-boost DC-DC converter that privileges the buck region through the extension of the duty-cycle range, enabling buck operation. In fact, the converter proposed here allows output voltages below the input voltage even with duty cycles higher than 0.6. We present the analysis, design, and testing of the extended buck-boost DC-DC converter. Several tests were conducted to illustrate the characteristics of the extended buck-boost DC-DC converter. Test results were obtained using both simulation software and a laboratory prototype.

The SEPIC converter is one of the unique DC-DC converters where this converter can maintain a constant output under varying and changing input conditions, a small input current ripple, and the same output polarity with its input, therefore this converter is widely used in systems with input voltages that vary from nominal voltage such as battery-based systems, and renewable energy-based generation fields such as photovoltaic. However, the characteristics of the output response in the open loop condition of the SEPIC converter have a considerable overshoot, the time to reach a steady state condition is quite long, and oscillations occur at the output voltage. Then, with changes in input voltage and load it will greatly affect the output response of the SEPIC converter. Therefore, fuzzy logics are employed in order to adjust the output voltage in the SEPIC converter when there are changes in input voltages and various loads. Based on the test results, the fuzzy logic on PID controller has a better output response than the PID controller, because the output of SEPIC converter uses proposed controller, has a slight voltage deviation and recovery time than the PID controller.

The four-switch buck-boost (FSBB) converter effectively reduces the average inductance current of FSBB when the input and output voltage is close to each other by using the four-mode operation, which alleviates the problem of limited duty cycle and low efficiency in the traditional control modes. However, the steady-state duty cycle mutation of FSBB with four-mode control will occur during mode switching, resulting in output voltage fluctuation. We analyzed the mechanism of duty cycle sudden change of four-mode control FSBB during mode switching, explored its influencing factors and governing laws, and proposed to use input voltage feedforward control to improve the smoothness of four-mode switching, so as to improve the response speed of output voltage when input voltage changes suddenly. The simulation results showed that after the input voltage feedforward control method was adopted, the four working modes can be switched smoothly in a wide input voltage range, the output voltage can be adjusted quickly, and the full load peak efficiency can reach 98%.

A positive buck-boost converter is a known DC- DC converter which may be controlled to act as buck or boost converter with same polarity of the input voltage. This converter has four switching states which include all the switching states of the above mentioned DC-DC converters. In addition there is one switching state which provides a degree of freedom for the positive buck-boost converter in comparison to the buck, boost, and inverting buck-boost converters. In other words the positive buck- boost converter shows a higher level of flexibility for its inductor current control compared to the other DC-DC converters. In this paper this extra degree of freedom is utilised to increase the robustness against input voltage fluctuations and load changes. To address this capacity of the positive buck-boost converter, two different control strategies are proposed which control the inductor current and output voltage against any fluctuations in input voltage and load changes. Mathematical analysis for dynamic and steady state conditions are presented in this paper and simulation results verify the proposed method.

Many electronic power distribution systems have strong needs for highly efficient AC-DC conversion that can be satisfied by using a buck-boost converter at the core of the power factor correction (PFC) stage. These converters can regulate the input voltage in a wide range with reduced efforts compared to other solutions. As a result, buck-boost converters could potentially improve the efficiency in applications requiring DC voltages lower than the peak grid voltage. This paper compares SEPIC, noninverting, and versatile buck-boost converters as PFC single-phase rectifiers. The converters are designed for an output voltage of 200 V and an rms input voltage of 220 V at 3.2 kW. The PFC uses an inner discrete-time predictive current control loop with an output voltage regulator based on a sensorless strategy. A PLECS thermal simulation is performed to obtain the power conversion efficiency results for the buck-boost converters considered. Thermal simulations show that the versatile buck-boost (VBB) converter, currently unexplored for this application, can provide higher power conversion efficiency than SEPIC and non-inverting buck-boost converters. Finally, a hardware-in-the-loop (HIL) real-time simulation for the VBB converter is performed using a PLECS RT Box 1 device. At the same time, the proposed controller is built and then flashed to a low-cost digital signal controller (DSC), which corresponds to the Texas Instruments LAUNCHXL-F28069M evaluation board. The HIL real-time results verify the correctness of the theoretical analysis and the effectiveness of the proposed architecture to operate with high power conversion efficiency and to regulate the DC output voltage without sensing it while the sinusoidal input current is perfectly in-phase with the grid voltage.

Eight-poles of various designs, including an eight-terminal network with three input and five output terminals, are needed to replace some power objects. Especially when only the input and output characteristics of electrical energy are of interest. The paper presents the eightterminal network equations with three input and five output terminals, establishing a connection between these characteristics. Equations of the A-form establish a connection between the input and output voltages and currents; the B-form equations establish a connection between the output and input voltages and currents; G-form equations establish a connection between the input current, output voltages and output voltage, output currents; H-form equations establish the relationship between the input voltage, output currents and output current, output voltages; the Yform equations establish a connection between the input and output currents and the input and output voltages; The Z-form equations establish the relationship between the input and output voltages and the input and output currents. When implementing these equations, attention should be paid to the difference in the directions of the currents in each individual case.

The buck-boost DC-AC inverter generates an alternating output voltage as the differential voltage of two DC-DC individual buck-boost converters that are driven with two 180/spl deg/ phase-shifted DC-biased sinusoidal references. The peak value of the inverter alternating output voltage does not depend on the direct input voltage. In addition, an advantage over the Boost DC-AC inverter is that the output voltages of both Buck-Boost converters are also independent of the direct input voltage. The difficulty of the topology lies in the control of both buck-boost DC-DC converters as they are required to work with variable operating-points. A double-loop control strategy is proposed for the buck-boost DC-DC converter with a new inner control loop for the inductor current and also a new outer control loop for the output voltage. These control schemes include different compensations that make possible a fast and accurate control of both converters with variable operating points. With these compensations, the controllers are easy to design, implement and develop. Furthermore, feedforward loops are included to increase the robustness of the inverter to external disturbances in both the input voltage and output load. The proposed control strategy is designed and implemented on a prototype 1.5 kW buck-boost DC-AC inverter. The control strategy is validated by means of both simulation and experimental tests. The results show that the proposed strategy achieves a robust, reliable and accurate control of the inverter even in hard situations such as nonlinear loads, sudden load changes and transient short circuits.

This paper presents the design of a digital controller for a 600 W Boundary-Conduction-Mode (BCM) interleaved boost converter used in an ac-dc Power-Factor-Correction (PFC) power supply. The output voltage of a typical boost PFC rectifier contains a 2nd harmonic ripple. Therefore to achieve good power factor, the output voltage compensator must have a low bandwidth, in order to sufficiently attenuate this 2nd harmonic component. As a result, the output voltage can suffer from poor transient response, especially at low input voltage. In this paper, a small-signal model of the output voltage dynamics is derived, where it is shown the open-loop gain of the system decreases with low input voltage. As a result, the output voltage transient response also deteriorates at low levels of input voltage. This can lead to poor voltage transient response for boost PFC converters that are designed to have an operating input line voltage range from 85 to 265 V. Having poor output voltage transient response is undesirable as it can lead to high peak over shoot on the output capacitors, or even worse, lead to an output voltage tracking failure. To correct this behaviour, an adaptive digital voltage compensator is designed to change gain at low input voltage, to ensure the output voltage maintains good transient response. Finally, the derived small-signal analysis, and output voltage compensator performance are experimentally verified on a 600 W interleaved BCM converter.

This paper discusses the Buck-Boost converter Design Using PID Control. Buck-Boost converter is a type of DC-DC converter that can convert DC voltage to a higher level or lower level. The buck-boost converter uses the PID system which is expected to produce a Buck-Boost converter output voltage in accordance with the setpoint and get a stable output voltage response, without overshooting and fast rise time. Tuning of PID parameters is done by the modified Ziegler Nichols 2 method, namely the original ZN, some overshoot, and No overshoot. Of the 3 types of tuning the PID has not gotten results in accordance with the design objectives, while it is still a high error and an unstable response. So the trial and error methods is used to get optimal results with PID parameters, namely Kp = 0.34, Ki = 0.350 and Kd = 0.019. The PID tuning of the trial and error method results in a stable response with steady-state error = 0, time delay = 0.37 s, rise time = 1.8 s, peak time = 0 and settling time = 1.8 s. From the results of the Buck-Boost converter output response proved the Buck-Boost converter using PID control was in accordance with the design goals .

Relevance Switching voltage converters are widely used in industry, which makes the study of such devices relevant. As a rule, these systems are built with feedback on the output voltage in order to stabilize it, so at the design stage it is necessary to calculate the control system in order to ensure stability and the required dynamic characteristics. The use of an input filter as part of pulse voltage converters, on the one hand, can improve the quality of the converter input current, and on the other hand, can lead to a loss of its stability as an aggregated «input filter — converter» system. This requires the development of methods for analyzing the dynamics of such systems. The applied mathematical models and computational methods must ensure maximum calculation speed, take into account the dynamic nonlinearities of pulsed power conversion systems and the periodic nature of electromagnetic processes with a frequency equal to or a multiple of the pulse modulation frequency. In some cases, chaotic oscillations may occur. The listed features make it relevant to use the point mapping method, based on nonlinear difference equations, which makes it possible to construct stability regions of the desired dynamic regime with minimal computer time. Aim of research Construction of a nonlinear dynamic model of a push-pull zero-DC voltage converter in the form of a nonlinear discrete Poincaré map, construction of two-parameter maps of dynamic modes, frequency characteristics of the system and, on their basis, identification of the main patterns of system behavior under conditions of changes in its input voltage and load resistance in a wide range for different input parameters filter. Research methods To analyze the dynamics, the following were used: small-signal modeling, point mapping method, frequency methods of stability analysis, theory of linear automatic control systems, theory of nonlinear dynamic systems, numerical methods for solving systems of nonlinear equations. Results A nonlinear dynamic model of a push-pull DC-DC converter with an input filter in the form of a Poincaré map has been constructed, and the main patterns of loss of stability of the desired dynamic mode have been identified when the input voltage and load resistance change over a wide range. The specificity of using various methods in analyzing the stability of the system under consideration is demonstrated. It is shown that the use of the point mapping method and accompanying methods for analyzing the stability of fixed points of dynamic modes makes it possible to use a single criterion for the loss of stability of the desired dynamic mode in different areas of system parameters.

We present an operation scheme for a dc–dc converter consisting of a class-E inverter and a class-E rectifier to always achieve zero-voltage zero- $dv\text{/}dt$ switching at a wide range of input and output voltages. To cope with the high sensitivity due to load variations, previous approaches either forgo the zero- $dv\text{/}dt$ turn- on switching conditions or required additional components and topological changes. Instead, the proposed strategy modulates the duty cycles and switching frequencies depending on the input and output voltages to always achieve zero- $dv\text{/}dt$ turn- on switching and, thus, minimizes switching losses, while preserving the structural simplicity of the converter. Experiments demonstrate the prototype converter maintaining the desired soft-switching condition under 80–200-V input voltage and 5–20-V output voltage variations. In an additional prototype, we implemented a similar design with synchronous rectification that achieves a peak efficiency of 92.3% at an input voltage of 80 V, an output voltage of 12 V, and an output power of 26.9 W.

This paper introduces a new approach for output voltage regulation in impedance control network (ICN) resonant dc–dc converters, in which the rectifier of the ICN converter alternates between full-bridge and half-bridge topologies. This approach, termed topology morphing control, allows the ICN converter to maintain soft switching across power levels while substantially reducing the output capacitance requirement and improving partial-power efficiencies compared to the conventional burst mode ( on/off ) control. A closed-loop control architecture for the ICN converter is also introduced, which regulates the converter's output voltage under input voltage and load variations while ensuring smooth transitions between the multiple operating modes of the proposed topology morphing control. A prototype 1-MHz, 120-W step-down ICN resonant converter designed for an input voltage range of 18–36 V, an output voltage of 12 V, and a 10:1 output power range has been built and tested with both burst mode control and the proposed topology morphing control. The topology morphing control reduces the output capacitance requirement in the prototype ICN converter by 57% and reduces converter losses at partial power levels by up to 46.5%. The prototype ICN converter is also tested under closed-loop control and is shown to successfully regulate its output voltage in the face of input voltage and load variations.

<span>In this paper, a design and control for the buck-boost converter, i.e., 1-plus-D converter with a positive output voltage, is presented, which combines the 1-plus-D converter and the synchronous rectified (SR) buck converter. By doing so, the problem in voltage bucking of the 1-plus-D converter can be solved, thereby increasing the application capability of the 1-plus-D converter. Since such a converter operates in continuous conduction mode inherently, it possesses the nonpulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Above all, both the 1-plus-D converter and the SR buck converter, combined into a buck–boost converter with no right-half plane zero, use the same power switches, thereby causing the required circuit to be compact and the corresponding cost to be down. Furthermore, during the magnetization period, the input voltage of the 1-plus-D converter comes from the input voltage source, whereas during the demagnetization period, the input voltage of the 1-plus-D converter comes from the output voltage of the SR buck converter.</span>

A constant frequency zero-voltage-switching (ZVS) control strategy with a minimum root mean square (rms) value of inductor current is proposed in this letter for the four-switch buck-boost (FSBB) dc-dc converter that is used as a 48 V intermediate bus pre-regulator in distributed power systems. The quadrilateral inductor current modulation is adopted to achieve ZVS operation. The four control time intervals are optimally selected such that the inductor current rms value is minimized, thus reducing the conduction loss. The proposed closed-loop ZVS control scheme can be implemented without sensing the load current, although the rms minimum current algorithm needs the input and output voltages and load current at given a steady-state condition. The control scheme is verified in a 300 W dc-dc prototype of the ZVS FSBB converter. The input voltage and load transition tests are provided to verify the closed-loop characteristics without sensing load current.

The two-switch buck-boost (TSBB) converter is suitable for wide input voltage applications. In order to achieve high efficiency over the entire input voltage range, the TSBB converter is operated in buck mode at high input voltage and boost mode at low input voltage. Such operation is called the two-mode control scheme. The objective of this paper is to propose an input voltage feed-forward (IVFF) method to reduce the influence of the input voltage disturbance on the output voltage. The small-signal models of the TSBB converter are built, and based on which, the IVFF functions under different operating modes of the TSBB converter are derived. The IVFF function in boost mode is simplified for easy implementation. The two-mode control scheme with IVFF compensation is then proposed for the TSBB converter, which realizes automatic selections of operating modes and the corresponding IVFF functions. Besides, nearly smooth switching between buck and boost modes is also guaranteed. For exhibiting the advantages of the proposed control scheme clearly, comparisons between the two-mode control with and without IVFF compensation have been presented in this paper, including the output signal of the voltage regulator and input-to-output voltage transfer function. Finally, a 250−500-V input, 360-V output, and 6-kW-rated power prototype is fabricated to validate the effectiveness of the proposed control scheme in the laboratory, and the experimental results show that the TSBB converter has an improved input transient response and high efficiency over the entire input voltage range with this proposed control scheme.