Powering Improvements in Medical Equipment With Higher Voltages, Denser Packaging, and Digital Controls

Interactive digital control using PMBus protocol can significantly improve performance, efficiency and reliability in high frequency low voltage DC (LVDC) microgrid applications using online optimization through shared clock and data. Modeling and analysis of digitally controlled standalone DC-DC converters, considering finite sampling delays, have been well reported in the past; however, modeling and analysis of fast scale stability and performance limits, under finite sampling delay and clock shift, have not been investigated so far in digitally controlled LVDC microgrids. This paper considers an intermediate bus architecture (IBA), consisting of an intermediate bus converter (IBC) followed by a point-of-load (PoL) converter, under clock-synchronized digital current mode control (DCMC). Considering the IBA dynamics, a discrete-time (DT) framework is proposed, and DT small-signal models are derived for stability and performance analysis. It is shown that the clock shift between individual converters and the sampling delays of their corresponding digital controllers have significant impacts on the fast-scale stability of the overall IBA system, which may lead to severe fast-scale instability with complex nonlinear phenomena and resulting in much higher (inductor) current ripple and RMS quantities. Simulation case studies are presented, and the stability boundaries are found to be consistent with the analytical predictions. The proposed framework will be helpful to design stable digital control in DC microgrids.

A novel digital adaptive voltage positioning (digital AVP) technique was proposed in [11]. Good transient performance had been achieved without using complicated control. In this paper, a small signal model is proposed for this mixed-signal digital controller. It is revealed by this small signal model that the inner current loop is in analog and the voltage loop is in digital, thus the controller can benefit from both: having valuable features of digital control but without limitations such as limit cycle. On the other hand, dynamic behavior of the voltage regulator with this digital AVP controller under large load transient is analyzed. With optimized bandwidth designed for switching stability, the VR with the digital AVP controller exhibits very excellent dynamic performance because of non-linear multi-mode control.

A novel digital adaptive voltage positioning (digital AVP) technique with dual-voltage-loop was proposed in. Good transient performance had been achieved without using complicated control. In this paper, a small signal model is proposed for this mixed-signal digital controller. It is revealed by this small signal model that the inner current loop is in analog and the voltage loop is in digital, thus the controller can benefit from both: having valuable features of digital control but without limitations such as limit cycle. On the other hand, dynamic behavior of the voltage regulator with this digital AVP controller under large load transient is analyzed. Decoupling between bandwidth and large transient response with this novel digital AVP controller is verified.

This paper presents a digital control technique to achieve valley switching in a bidirectional flyback converter used to drive a dielectric electroactive polymer-based capacitive incremental actuator. This paper also provides the design of a low input voltage (24 V) and variable high output voltage (0–2.5 kV) bidirectional dc–dc flyback converter for driving a capacitive incremental actuator. The incremental actuator consists of three electrically isolated mechanically connected capacitive actuators. It requires three high-voltage (HV) (2–2.5 kV) bidirectional dc–dc converters to accomplish the incremental motion by charging and discharging the capacitive actuators. The bidirectional flyback converter employs a digital controller to improve the efficiency and charge/discharge speed using the valley switching technique during both charge and discharge processes, without the need to sense signals on the output HV side. Experimental results verifying the bidirectional operation of a HV flyback converter are presented using a 3-kV polypropylene-film capacitor as the load. The energy-loss distributions of the converter are presented when 4- and 4.5-kV HV mosfet s are used on HV side. The flyback prototype with a 4 kV mosfet demonstrated 89% charge energy efficiency to charge the capacitive load from 0 V to 2.5 kV, and 84% discharge energy efficiency to discharge it from 2.5 kV to 0 V.

This paper presents a integrated high voltage digital-to-analog converter array, which is designed by using a 0.35µm high voltage CMOS technology(AMS H35), and can be applied in high voltage applications up to 120V. The DAC array has 16 high voltage DACs controlled by a digital controller on chip. To fulfil the requirement of communication system with reconfigurable antenna implemented using materials which have voltage dependent capacitance, the DACs are designed to have 8 bits of resolution. In order to improve the accuracy and decrease the required area, each independent DAC is implemented by a low voltage DAC and a high voltage amplifier for boosting the controllable output voltage. Since the current consumption from the high voltage power supply is only 1.28mA, it is possible to be powered by a charge pump which generates high voltage power supply from a battery. The proposed HV DAC array can drive up to 16 individual channels of antenna array with different voltages from 0V to 120V. It will greatly reduce the complexity and cost of mobile applications required high voltage. The feasibility is proved by post-simulation result.

Because of its advantages of small size, high positioning accuracy, simple control, voice coil motor (VCM) is widely used in high-precision positioning systems such as disk drive, medical equipment, precision electronic tubes, etc. Digital control is the most commonly used control method for VCM positioning system, since the digital control method has less loss than the analog control method. However, the problem of large current ripple caused by PWM chopping occurs in digitally controlled system. To deal with this issue, LCL filter is combined with VCM in this paper. The VCM position servo control system with LCL filter turns to a 5th order system. Moreover, LCL filter resonance is a problem that must be considered. In this paper, traditional three-loop structure with PID regulator is first designed for the system, and the parameters tuning and LCL filter resonance suppression are studied. An additional capacitive current sensor is needed in this method to achieve LCL filter resonance suppression. In order to eliminate the additional capacitive current sensor, and further improve the position response speed, this paper proposes a direct position servo control method based on active disturbance rejection control (ADRC). ADRC method can estimate and compensate the disturbances in real time, so the system has better robustness. In addition, LCL filter resonance is suppressed by ADRC active damping, so there is no need for an additional capacitor current sensor.

In high-performance magnetic resonance imaging systems, the gradient driver is required to supply the gradient coil with a large current (>600 A) and a high voltage (>2000 V) to achieve a strong gradient field and a fast slew rate. In addition, extremely high fidelity for reproducing the current command from the central system is very critical to imaging quality. This paper presents the solutions for the different elements of the driver: 1) high-bandwidth (BW) power inverter; 2) ripple cancelation filter; 3) multioutput power supply (PS); and 4) digital control. A high-BW power inverter requires a stacked-bridges structure to achieve a high output ripple frequency with the existing commercial power semiconductor modules. The high voltage and the high frequency for large power modules can be obtained easier and with lower loss using the new silicon carbide devices. The control needs a digital implementation and a very fast processor. Digital control provides compensation and feedforward to improve the response. A capability improvement is obtained by reducing the switching frequency when large currents with a very low-frequency variation are needed. The control can handle it very well, but the filter has to be designed to eliminate more than one ripple frequency. Finally, many PS solutions have been used for multiple isolated outputs, but digital control compensation permits the use of much simpler unregulated PS and keeps the performance. A 2 MVA, 900 A/1200 V, platform has been built and fully tested. The experimental results proved the validity of the proposed structure and the modulation technique.

This paper presents a digitally controlled boost converter IC for high output voltage and fast transient applications. Thus, it is well applicable in automotive and industrial environments. The 3 V-to-6 V input voltage, 6.3 V output voltage, 1 A boost converter IC is fabricated in a 180 nm BCD technology. Digital control enables cost savings, advanced control concepts, and it is less parameter sensitive compared to common analog control. A 90 ns latency, 6-bit delay line ADC operates with a window concept, meeting high resolution requirements, e.g. in car battery applications. An output voltage live tracking is included for extending the ADC conversion window. A charge pump DAC provides high resolution, monotonicity, and short 128 ns conversion time. Further, a standard digital PI controller is enhanced by a simple but effective Δ V/Δt-intervention control. It results in 2.8x reduced output voltage deviations in case of load steps, scaling down the output capacitor value by the same factor.

The demanding for high energy density as well as high safety is still an important threshold for battery commercialization. Next‐generation layered LiNixCoyMn1−x−yO2 (NCM) cathodes will meet the specific energy required for driving range of at least 300 miles from a single charge to guarantee the success of electric vehicles. Extending operating voltage of NCM cathode materials is considered as an effective way to increase energy density of lithium ion batteries. However, unstable electrode electrolyte interface (CEI) limits the electrochemical performance of NCM cathodes when operating at high voltages (>4.3 V). In this review, underlying factors and mechanisms that result in the failure to form a robust CEI are analyzed, including surface phase reconstruction, stress‐induced cracking, transition metal dissolution, electrolyte decomposition and oxygen redox reaction. Then, progress on how to improve and stabilize CEI is summarized. To bridge the gap between current and next generation automotive batteries, it is expected that the situation of NCM electrode materials at high voltage to be fine‐tuned with available variables such as nickel content, packaging density and loading level. Moreover, more detailed work on designing and studying a reliable CEI can help the application of NCM cathodes under high voltage.

Typical line-commutated high power converters for HV-AC systems are thyristor controlled reactors (TCR), thyristor switched capacitors (TSC), high voltage direct current transmission (HVDC) and rectifiers for DC arc furnaces. These high power converters require higher dynamics and higher quality of their control hardware than applications of smaller size because they are directly affected by disturbances in the HV-network. In order to reach a high system availability the converter has to remain in operation and to recover within a few cycles. To meet the requirements of control accuracy and speed in new installations, only digital controls are used. Even old analogue equipment is being replaced because of the technical and economic advantages of digital systems over analogue ones. The interface between power electronics and control system, called firing control, provides line synchronous firing pulses to the thyristor valves according to the firing angle ordered by the control. Implementation of the digital firing control requires high computing performance. The computer hardware used performs the necessary filtering and achieves better accuracy and more equidistant firing than the former analogue hardware.

There exists low voltage in circuit of domestic and imported medical equipment and it is what we call power supply. In the past, equipment mainly uses transformer to step down the voltage of power supply. With the progress of science and technology, the technique is gradually replaced by SMPW (switch mode power supply) which is extensively applied to various types of medical equipment due to the high efficiency and wide voltage range. The mains power supply is rectified and filtered into a DC high voltage and then use the switch circuit and energy storage elements to convert them into a variety of required DC voltage output, output DC voltage level can be adjusted by changing the off time (namely Mark-Space Ratio) of switching circuit.

Isolated Bi-Directional DC-DC converters are commonly used in automotive and data storage applications where energy is transferred between a high-voltage DC bus and a low-voltage DC bus/battery in a bi-directional fashion. A typical implementation includes a phase-shifted full-bridge (PSFB) with synchronous rectification that controls power flow from the high-voltage bus to the low-voltage battery in step-down (buck) mode, and a current-fed push-pull converter that controls the reverse power flow from the low-voltage battery to the high-voltage bus in step-up (boost) mode. The major challenges to implement this PSFB bi-directional operation are; (1) High voltage bridge-FET rectification during reverse power flow (boost mode) in current-fed push-pull converter, (2) Fast seamless transitions between buck and boost modes. This paper presents system performance improvements obtained using 50% duty with phase-shift PWM control scheme to control high voltage bridge-FET rectification in reverse power flow. A new method that provides fast seamless transitions between buck and boost modes of operations is also presented. Experimental results obtained using a wide input range 400V ←→ 12 V, 300W digitally controlled isolated bi-directional DC-DC converter are presented.

In this paper, self-resonant characteristics of transformers were analyzed in accordance with changes of characteristics regarding to the stray capacitance, the volume of winding and the winding ratio were organized by formulas. Generally, the stray capacitance is considered as an unnecessary factor in processing transformers design as well as one of the inherent characteristics. In particular, these characteristics can be appeared clearly in the high frequency driving and Electrical resonance occurs in transformer, according to coupling with a magnetic factor at a particular frequency. In the case of high-voltage output applications, such as medical equipments, It is required to output high-voltage gain. Therefor, If Self-Resonant Characteristic is applied to High-Voltage transformer design, Not only the transformer and circuit but also related the system size can be reduced. So we propose it as one of additional high voltage transformer design methods.

Here are considered test results from a new dc high-voltage meter based on the x-ray spectral method proposed in [i, 2]. This meter, the RIVN, has been certified as a standard means of measurement in a test system for the high-voltage range40-120 kV, and the purpose of the study has been to check the scope for maintaining the basic error within 0.15% limits. The metrological aspects of using this meter have been discussed [3-6]. The proposed method enables one to calibrate the scale from the known energies of ~-ray sources without linkage to the volt standard [6]. The RIVN has the advantage that one can measure and monitor high voltages wihtout direct connection to the current circuits, which is preferable in medical equipment use.

Focus is placed on all aspects of electrical energy as well as innovation in energy generation and delivery, three different approaches, and efficient technologies in energy and energy systems research. Research projects focus on systems and equipment for converting, supplying, and using energy as a form of electricity. In order to improve quality and efficiency and to promote the gradual materialization of intelligent, efficient energy, power electronics are increasingly a more fundamental component of power systems. Power systems use a wide variety of power electronics. Power systems is the physical study of converting electrical energy from one medium to another. More than 80% of the total electricity produced at a global average rate of 3.4 billion kilowatts per hour per year is reprocessed or recovered in industries like electronics. Electrical energy is processed or converted using power electronics converters, often known as power converters or switching converters. There are two types of electricity: AC power and DC power. Depending on the kind of power it uses, the distribution system is split into AC distribution systems and DC distribution systems. design about an electrical power system must include power system analysis. To ensure that the electrical system, including the system components, is appropriately defined to operate as intended, resist anticipated stress, and be safeguarded from failures, calculations and simulations are carried out. Power electronic benefits: power density that is high. improved energy conversion efficiency of up to 99%. Switching power supplies are employed in medical equipment with acoustically sensitive industrial applications to their dependability and efficiency. In general, issues like service disruptions and power outages are related to the reliability of the power supply. It is commonly stated that this is an attempt to rely on codes that are directly pertinent to the user. Standard dependency index values for US purposes include SAIFI, SAIDI, and CAIDI. DEMATEL (Decision Making Trial and Evaluation Laboratory) They are divided into analysis using the Nonmetal mineral product industry, General equipment manufacturing, Mining and washing of coal, Textile industry, Food manufacturing industry It is the interaction between the factors Visualized and assesses dependent relationships Through the structural model Also deals with identifying important. Evaluation parameters: Analog & Digital Electronics, Power Systems, Electric Circuits, Electric Machines and Digital Controllers. Power Systems and Power Electronics in Analog & Digital Electronics is got the first rank whereas is the Electric Circuits is having the Lowest rank. Power Systems and Power Electronics in Analog & Digital Electronics is got the first rank whereas is the Electric Circuits is having the Lowest rank