Hybrid Switch Research Articles

Precise Electro-thermal Power Loss Model of a Three-level ANPC Inverter with Hybrid Si/SiC Switches

Hybrid Si/SiC switches constituting a parallel connection of a lower current rated SiC MOSFET and a higher current rated Si IGBT are becoming very attractive solution for designing high frequency and high-power density power electronic converters. Due to the complementary nature of Si IGBT devices (smaller inverter cost and smaller conduction loss) and SiC devices (smaller switching loss and higher junction temperature capability), these novel switch device configurations enable a good tradeoff between cost and efficiency for high power converter applications. One such recent application of hybrid Si/SiC switches for efficiency-cost optimization is an Si/SiC hybrid switch based ANPC inverter proposed in Ref. [30]. In Ref. [30] the topology structure, modulation strategy and the efficiency-cost benefits of the proposed ANPC inverter is presented. In this paper a precise electro-thermal power loss model for this ANPC inverter topology will be presented based on the modulation strategy of the inverter and the operating characteristics of the Si/SiC hybrid switches. The power loss model development takes into account how the current sharing between the two internal devices of the Si/SiC hybrid switches and their corresponding gate control method affects their power loss. A brief introduction to the topology structure and operation principle of the Si/SiC based ANPC inverter is first highlighted to provide context for readers and then a detailed description of the proposed electro-thermal power loss model is presented. The precision of the electro-thermal power loss model introduced in this paper is then validated using experimentally measured energy loss, device temperature and inverter efficiency data.

An optimized parameter design method of SiC/Si hybrid switch considering turn-off current spike

In order to reduce the switching loss of SiC MOSFET/Si IGBT (SiC/Si) hybrid switch, the switching mode that turn off the Si IGBT prior to the SiC MOSFET is generally adopted to achieved the zero-voltage switching operation of IGBT. The minority carrier in N-base region of the IGBT are recombined in the form of exponential attenuation due to the conductivity modulation effect. When the SiC MOSFET is turned off, if the carrier recombination process of the IGBT is not finished, it needs to bear a large collector–emitter voltage change rate, resulting in apparent current spike. This current spike will increase the current stress of the device and produce additional turn-off loss. The equivalent model of double pulse test circuit of SiC/Si hybrid switch considering parasitic parameters is established, and the turn-off transient process is given analytically. The influence of turn-off delay time, circuit parameters and working conditions on current spike are analysed quantitatively. Combined with the consideration of device stress and comprehensive turn-off loss, an optimized circuit design method of SiC/Si hybrid switch considering turn-off current peak is proposed, which provides theoretical and design guidance for high reliability and high efficiency SiC/Si-based converters.

Dynamic Gate Delay Time Control of Si/SiC Hybrid Switch for Loss Minimization in Voltage Source Inverter

The voltage source inverter (VSI) based on the Si/SiC hybrid switch (HyS) offers a better cost/performance tradeoff than the full-SiC VSI design. However, the Si/SiC hybrid VSI bears huge power losses with fixed gate turn-off delay time. In this article, a novel dynamic optimal gate turn-off delay time control method of Si/SiC HyS-based VSI is proposed to achieve the maximum efficiency over a wide load range. The optimal gate turn-off delay time is obtained by a load current-based mathematic power loss model. A 20-kHz 5-kW prototype of the single-phase constant current (CC) VSI using a 1200-V/25-A insulated gate bipolar transistor (IGBT) and a 1200-V/12.5-A SiC MOSFET is built to validate the proposed method. In comparison with the fixed gate turn-off delay time control method, the proposed method achieves 8% total power loss reduction and 0.24% conversion efficiency improvement at 1.5-kW output power.

DC Metal Contact Non-arc Hybrid Switch and its Multiple Operation Test

DC Metal Contact Non-arc Hybrid Switch and its Multiple Operation Test

Performance Improvement of the Hybrid Switch Reluctance Motor by Notching Method

Hybrid switch reluctance motors are the family of switch reluctance motors (SRMs) that attenuate the magnetic saturation and increase the air gap magnetic flux by exploiting permanent magnets. The permanent magnet auxiliary air gap flux can affect the average torque and ripple. Commonly, the torque ripples reduction comes with the average torque drop. In this paper, the torque ripple reduction and average torque improvement are achieved for a 6/10 pole hybrid switch reluctance motor by inserting two symmetrical notches on its rotor. Also, the lengths of magnet and rectangular notches are optimized by the finite element method and sensitivity analysis. The comparison of the optimized design with the initial one carried out by finite element proves the efficiency of the proposed model.

Study on the CM EMI Generation Characteristics of the Si/SiC Hybrid Switch at Different Switching Patterns and Gate Resistors

The switching patterns and gate resistor of the Si/SiC hybrid switch are the key to realizing its own highly efficient and reliable operation. However, as an important performance indicator, the common mode (CM) electromagnetic interference (EMI) noise caused by the Si/SiC hybrid switch lacks comprehensive research, which means that it is not clear how the switching patterns and gate resistor affect CM EMI. In this paper, the Si/SiC hybrid switch-based boost converter is established at first. Then, by analyzing the spectral characteristics of the CM voltage of the Si/SiC hybrid switch, the CM EMI generation characteristics of the Si/SiC hybrid switch at different switching patterns and gate resistors are revealed. Furthermore, the analysis and experimental results can be used to comprehensively guide the design of the gate drive pattern, gate resistor, and EMI suppression strategy.

Redundancy Management Strategy for a Silicon/Silicon-Carbide Hybrid Switch-Based Modular Inverter System

In order to further improve the device utilization of a modular inverter system after the failure of a single inverter unit, a silicon (Si)/silicon-carbide (SiC) hybrid switch with high redundancy can be taken to achieve this goal. However, when the failure of the Si/SiC hybrid switches in the inverter unit occurs, the performance of this modular inverter adopting the fixed switching strategy (Fixed switching pattern and switching frequency) may be reduced. In this paper, a redundancy management strategy is proposed to prevent the performance of the Si/SiC hybrid switch-based modular inverter from reducing after the failure of the Si/SiC hybrid switches occurs. Taking the modular inverter system composed of two inverter units as an example, the experiment results demonstrate that compared to the healthy operating conditions, the increase of the voltage’s THD is smaller than 1.4%, and the increase of the total loss is smaller than 0.89%.

Dynamics of a stochastic staged progression model of HIV transmission with a hybrid switch

In this paper, we investigate the dynamics behavior of stochastic hybrid switching staged progression model for the transmission of HIV. The method used in this paper is Lyapunov functions analysis. We establish sufficient conditions for extinction of disease. Especially, we conclude that there is a stationary distribution for the stochastic system and it has ergodicity under appropriate conditions. Finally, some examples and their simulations are provided to illustrate the theoretical results.

Improving the design of super-lift Luo converter using hybrid switching capacitor-inductor cell for PV system

<p>In this article, an improvement to the positive output super-lift Luo converter (POSLC) has been proposed to get high gain at a low duty cycle. Also, reduce the stress on the switch and diodes, reduce the current through the inductors to reduce loss, and increase efficiency. Using a hybrid switch unit composed of four inductors and two capacitors it is replaced by the main inductor in the elementary circuit. It’s charged in parallel with the same input voltage and discharged in series. The output voltage is increased according to the number of components. The gain equation is modeled. The boundary condition between Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM) has been derived. Passive components are designed to get high output voltage (8 times at D=0.5) and low ripple about (0.004). The circuit is simulated and analyzed using MATLAB/Simulink. Maximum power point tracker (MPPT) controls the converter to provide the most interest from solar energy.</p>

Performance Evaluation of Si/SiC Hybrid Switch-Based Three-Level Active Neutral-Point-Clamped Inverter

In this paper, two types of Silicon (Si) IGBT and Silicon Carbide (SiC) hybrid switch (Si/SiC HyS) based three-level active neutral-point-clamped (3L-ANPC) inverter are proposed for high efficiency and low device cost. The proposed Si/SiC HyS-based 3L-ANPC inverters are compared with the full Si IGBT, full SiC MOSFET, and Si with SiC devices-based hybrid 3L-ANPC solutions on the inverter efficiency, power capacity, and device cost. It is shown that compared with the full Si IGBT 3L-ANPC solution, the inverter efficiency improvement by Si/SiC HyS is 2.4% and 1.8% at light load condition and heavy load condition, respectively. Compared to the full SiC MOSFET solution and 2-SiC MOSFETs hybrid scheme, the device cost of 2-Si/SiC HyS-based 3L-ANPC is reduced by 78% and 50% with 0.28% and 0.21% maximum inverter efficiency sacrifices. The testing results show that the proposed Si/SiC HyS-based 3L-ANPC inverter is a cost-effective way to realize high inverter efficiency. Between the two proposed Si/SiC HyS-based 3L-ANPC inverters, the 2-Si/SiC HyS-based 3L-ANPC inverter has lower device cost which makes it more suitable for cost-sensitive and high efficiency applications. While the 4-Si/SiC HyS-based 3L-ANPC inverter has higher output power capacity, making it a better candidate for high power density, high power capacity, and high efficiency applications.

Study of self-charging features in hybrid vehicle

Pollution and energy crises become more and more visible, and Hybrid Electric Vehicles (HEVs) are gaining more and more popularity around the world. To study the perception of alternative technology in an automobile, the project "Hybrid Vehicle Using Self-Charging Functions" is being carried out. A hybrid vehicle uses two or more different types of energy and combines it with electrical power. When the motor is started, the magnetic coil present in the crank starts to rotate. The rotation creates a higher voltage flux. In this case, an additional alternative magnet coil is connected in parallel with the magnet coil using gears. As the coil rotates, the energy generated in the main coil is used for ignition, while the energy generated in the alternate coil is sent to the rectifier and stored in the battery. While the car runs out of fuel, the hybrid switch is activated, then the energy stored in the battery is transferred to the wheel hub, and it starts to work. Since ancient times, people have been using vehicles for transportation and some personal needs. It pollutes the environment with gasoline and diesel fuel. It is burned in the engine for energy, but as some unburned gases come out, it affects the human respiratory system. Therefore, the automotive industry has introduced a battery vehicle (hybrid vehicle). It consumes zero emissions and is environmentally friendly. For a while, it only appeared in cars, not two-wheelers, so for a change, if it creates a hybrid two-wheeler combined with a motor and battery, it will have power, fuel efficiency, and fewer emissions. It has power and environmental fixes in a two-wheeler. When driving at an average speed of 0 to 50 mph, it consumes more fuel due to high torque instead of power from the engine. It receives power from the battery above 50 to 100, and when the engine comes to work, there is power from the engine at that time with low torque, so the motorcycle will not consume much fuel, which means that in motion, the two-wheeler is running on battery, and in the absence of motion, in an engine with such low emissions.

Capacitor Commutation Method for MVDC Hybrid Circuit Breakers

The medium voltage DC (MVDC) type system can connect multiple terminals to a common MVDC bus, so it is possible to connect several renewable DC power sources to the common MVDC bus, but a DC circuit breaker is needed to isolate short circuit accidents that may occur in the MVDC bus. For this purpose, the concept of a hybrid DC circuit breaker that takes advantage of a low conduction loss contact type switch and an arcless-breaking semiconductor switch has been proposed. During break the hybrid switch, a dedicated current commutation device is required to temporarily bypass the load current flowing through the main switch into a semiconductor switch branch. Existing current commutation methods include a proactive method and a reverse current injection method by a LC (Inductor-capacitor) resonant circuit. This paper proposes a power circuit of a new MVDC hybrid circuit breaker using a low withstanding voltage capacitor branch for commutation and a sequence controller according to it, and verifies its operation through an experiment.

A Novel Single-Gate Driver Circuit for SiC+Si Hybrid Switch With Variable Triggering Pattern

Hybrid switches are attracting increasing attention recently, due to their high efficiency and low cost. Normally, two separated gate drivers and driving signals are needed for the hybrid switch, which leads to more cost and more control complexity. A novel gate driver circuit for SiC+Si hybrid switches is proposed using single driving signal and single-gate driver in this article. Two simple resistance-capacitance (RC) delay circuits are used for generating different time-delays required by two different triggering patterns to provide more flexibility. The detailed operation principles, mathematical analysis, and the guidance for the selection of key components of the proposed circuit are provided. The merits of the proposed driver are: first, simple structure; second, low control complexity; third, more flexibility; and fourth, low cost. A 2-kW Silicon Carbide (SiC)-MOSFET+Si-insulated gate bipolar transistor (IGBT) hybrid switch buck converter is built to validate the proposed gate driver circuit. The analysis and experimental results match very well, which shows the effectiveness and merits of the proposed method.

Multifunctional optoelectronic device based on graphene-coupled silicon photonic crystal cavities.

We present a hybrid device based on graphene-coupled silicon (Si) photonic crystal (PhC) cavities, featuring triple light detection, modulation, and switching. Through depositing single-layer graphene onto the PhC cavity, the light-graphene interaction can be enhanced greatly, which enables significant detection and modulation of the resonant wavelength. The device is designed to generate a photocurrent directly by the photovoltaic effect and has an external responsivity of ∼14 mA/W at 1530.8 nm (on resonance), which is about 10 times higher than that off-resonance. Based on the thermo-optical effect of silicon and graphene, the device is also demonstrated in electro-optical and all-optical modulation. Also, due to the high-quality (Q) factor of the resonate cavity, the device can implement low threshold optical bistable switching, and it promises a fast response speed, with a rise (fall) time of ∼0.4 μs (∼0.5 μs) in the all-optical switch and a rise (fall) time of ∼0.5 μs (∼0.5 μs) in the electro-optical hybrid switch. The multifunctional photodetector, modulator, and optical bistable switch are achieved in a single device, which greatly reduces the photonic overhead and provides potential applications for future integrated optoelectronics.

Switching Time Delay Optimization for “SiC+Si” Hybrid Device in a Phase-Leg Configuration

Compared to SiC MOSFET, the switching loss of Si IGBT is much higher due to its slow switching speed and tail current. Si IGBT/SiC MOSFET hybrid switch device can reach to optimal performance with low static and dynamic loss, which can improve the current capacity of SiC devices and reduce the power loss of Si IGBT based converters. With the separated gate control signals, the switching moments of the two devices can be controlled independently to ensure Si IGBT under zero-voltage switching (ZVS) conditions. This measurement tends to reduce the switching loss of Si IGBT. However, the switching time delay between these two devices has significant impacts on its power loss. In this paper, the switching time delay optimization method is proposed to minimize the power loss of the hybrid switch. The static and dynamic characteristics of Si IGBT/SiC MOSFET hybrid-paralleled switch are studied, and a generalized power loss model for hybrid switch is developed. The influence of switching time delay on the characteristics of hybrid switch is analyzed and verified through double pulse tests in a phase-leg configuration. The experimental results show that the optimal turn-on delay time is that the two devices turn on at the same time and the turn-on loss can be reduced by about 73% compared with the solely Si IGBT and by about 52% compared with the solely SiC MOSFET. While the optimal turn-off sequence is that the Si IGBT turns off ahead of the SiC MOSFET. Under the proposed optimal turn-off delay time of the hybrid switch, the turn-off loss is reduced by about 61.4%. This optimization strategy is used in a Buck converter to verify the superiority of the SiC/Si hybrid switch and the optimal switching sequence. Simulation results show that the optimal switching sequence is consistent with theoretical analysis, and the efficiency is improved by 2.5% compared with Buck converter using solely Si IGBT.

A novel gate driver for Si/SiC hybrid switch for multi‐objective optimization

A novel gate driver with simple functional and structural integration is proposed here, which splits the input gate signal and outputs two separate signals with a dedicated delay time to drive the two constitutional switches, aiming at the cost-effectiveness and power loss reduction of the Si/SiC hybrid switch. The dependency of the hybrid switch's thermal and efficiency performance on the parameters of the gate driver are theoretically and experimentally investigated in a 9 kW 20 kHz Si/SiC hybrid switch based boost converter. A novel load current dependent gate control strategy is proposed to be implemented in the proposed gate driver to achieve the high conversion efficiency under light to medium load condition and balanced junction temperature between the two internal devices under heavy load conditions. The experimental results based on a 20 kHz boost converter show that the Si/SiC hybrid switch with the novel gate driver and optimal current dependent control strategy offers a 163% and 10% rise in power handling capability, respectively, compared to that using the all-IGBT device and all-SiC MOSFET device, and yet a considerably lower device cost.

Scalable SiPh-InP Hybrid Switch Based on Low-Loss Building Blocks for Lossless Operation

We design and experimentally demonstrate scalable 2 × 2, 4 × 4 and 8 × 8 silicon photonic (SiPh) thermo-optic switch exhibiting low loss, low crosstalk, low power penalty, and BER below 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-10</sup> for payload data transmission. Less than 3.13 dB insertion loss (IL) and approximately 20.5 dB crosstalk is measured in the 8 × 8 SiPh banyan switch with thermal phase shifters. We also report on a semiconductor optical amplifier (SOA) in an indium phosphide (InP) technology platform with 25 dB gain and 7 dB noise figure enabling to transmit optical signals with large OSNR. Combining SiPh and InP technologies, we propose a lossless hybrid switch matrix with distributed SOA-based gain capable of transmitting data with near zero loss and low crosstalk over a large switching matrix. In hybrid SiPh/InP switches, the SOA gain compensates for the SiPh switch loss at the cost of amplified spontaneous emission (ASE) noise but mitigated by bandpass optical filters. Lower IL from the SiPh switch requires less gain from the SOAs leading to less OSNR degradation. Experimentally validated building blocks confirmed scalability up to 64 × 64 in SiPh-InP hybrid platform.

Hybrid Low-Frequency Switch for Bridgeless PFC

Traditionally, for the bridgeless PFC, the low-Ron Si super-junction (SJ) mosfets are utilized to reduce the loss on the low-frequency switches. However, the high cost of the low-Ron Si SJ mosfet is an issue. Therefore, this letter proposes a hybrid low frequency switch which hybrids a high-Ron and low-cost Si SJ mosfet and a high current and low-cost Si diode. This hybrid switch achieves the low conduction loss under light load conditions due to the internal mosfet and achieves the low conduction loss under heavy load conditions due to the parallel diode. This hybrid switch combines the benefits of the mosfet and the diode with very low cost. This switch is very suitable for the high-efficiency bridgeless PFC rectifiers. The analytical and the experimental results based on the implemented hybrid switch verify the performance of the hybrid switch.

A Variable-Frequency Current-Dependent Switching Strategy to Improve Tradeoff Between Efficiency and SiC MOSFET Overcurrent Stress in Si/SiC-Hybrid-Switch-Based Inverters

Reliability remains an issue for the Si/SiC hybrid switch adopting the conventional switching strategy of the internal SiC MOSFET that turns on earlier, and off later. Such issue is attributable to the overcurrent stress under the heavy load operating condition, which adversely affects the SiC MOSFET during the gate delay time. To solve this problem without increasing the extra power loss, a novel variable-frequency current-dependent switching strategy combining the variable switching pattern strategy, and the variable pulsewidth modulation (PWM) frequency strategy is proposed. Variable switching pattern strategy can avoid the overcurrent stress of the SiC MOSFET at the heavy load operating condition, and the designed optimal delay time in different switching patterns can achieve the compromise between the excellent reliability, and the power loss of Si/SiC hybrid switch. Variable PWM frequency strategy can effectively reduce the switching loss of the Si/SiC hybrid switch by decreasing the switching frequency around the peak current region. An Si/SiC-hybrid-switch-based single-phase inverter platform is constructed and tested. Test results show that the power loss of the single-phase inverter adopting such switching strategy outperforms the current-dependent switching strategy with 9.4% reduction of power loss, and overcurrent stress of SiC MOSFET is avoided.

A Normally-off Copackaged SiC-JFET/GaN-HEMT Cascode Device for High-Voltage and High-Frequency Applications

A 1200-V/100-mΩ silicon carbide (SiC) junction field-effect-transistor (JFET)/ gallium nitride (GaN) high-electron-mobility-transistor (HEMT) hybrid power switch is demonstrated, which features a flip-chip copackaged cascode configuration incorporating a vertical SiC JFET and a lateral GaN-HEMT. The high-voltage SiC-JFET provides the high-voltage blocking capability while the low-voltage GaN-HEMT enables the normally- off gate control with superior switching characteristics. Compared to conventional SiC-JFET/Si- mosfet cascode devices, the SiC-JFET/GaN-HEMT cascode device exhibits fast switching speed, which has been validated by systematic characterizations including static/dynamic device-level measurements and board-level hard-switching tests. Meanwhile, the device is free from several notorious issues of high-voltage GaN power transistors such as dynamic on -state resistance degradation and threshold voltage shift. Such a wide-bandgap semiconductor-based hybrid switch is suitable to be deployed in high-power and high-efficiency power conversion systems.