Feed aggregator

done with a 4$ iron, unleaded solder and no flux submitted by /u/Doughnut_Opposite [link] [comments]

Current-mode control LLC considerations

Inductor-inductor-capacitor (LLC) serial resonant circuits, as shown in Figure 1, can achieve both zero voltage switching on the primary side and zero current switching on the secondary side in order to improve efficiency and enable a higher switching frequency. In general, an LLC converter uses direct frequency control, which has only one voltage loop and stabilizes its output voltage by adjusting the switching frequency. An LLC with direct frequency control cannot achieve high bandwidth because there is a double pole in the LLC small-signal transfer function that can vary under different load conditions [1] [2]. When including all of the corner conditions, the compensator design for a direct frequency control LLC becomes tricky and complicated.

Current-mode control can eliminate the double pole with an inner control loop, achieving high bandwidth under all operating conditions with a simple compensator. Hybrid hysteretic control is a method of LLC current-mode control that combines charge control and ramp compensation [3]. This method maintains the good transient performance of charge control, but avoids the related stability issues under no- or light-load conditions by adding slope compensation. The UCC256404 LLC resonant controller from Texas Instruments proves this method’s success.

Figure 1 LLC serial resonant circuits that achieve both zero voltage switching on the primary side and zero current switching on the secondary side. Source: Texas Instruments

Principles of LLC current-mode control

Similar to pulse-width modulation (PWM) converters such as buck and boost, peak current-mode control controls the inductor current in each switching cycle and simplifies the inner control loop into a first-order system. Reference [2] proposes LLC charge control with the resonant capacitor voltage.

In an LLC converter, the resonant tank operates like a swing. The high- and low-side switches are pushing and pulling the voltage on the resonant capacitor: when the high-side switch turns on, the voltage on the resonant capacitor will swing up after the resonant current turns positive; conversely, when the low-side switch turns on, the voltage on the resonant capacitor will swing down after the resonant current turns negative.

Energy flows into the resonant converter when the high-side switch turns on. If you remove the input decoupling capacitor, the power delivered into the resonant tank equals the integration of the product of the input voltage and the input current. If you neglect the dead time, Equation 1 expresses the energy in each switching cycle.

In Equation 1, the input voltage is constant, and the input current equals the absolute of the resonant current. So, you can modify Equation 1 into Equation 2.

Looking at the resonant capacitor, the integration of the resonant current is proportional to the voltage variation on the resonant capacitor (Equation 3).

Equation 4 deduces the energy delivered into the resonant tank.

From Equation 4, it is obvious that the energy delivered in one switching cycle is proportional to the voltage variation on the resonant capacitor when the high-side switch turns on. This is very similar to peak current control in a buck or boost converter, in which the energy is proportional to the peak current of the inductor.

LLC current-mode control controls the energy delivered in each switching cycle by controlling the voltage variation on the resonant capacitor, as shown in Figure 2.

Figure 2 The LLC current-mode control principle that manages the energy delivered in each switching cycle by controlling the voltage variation on the resonant capacitor. Source: Texas Instruments

LLC current-mode control with MCUs

Figure 3 shows the logic of a current-mode LLC implemented with the TMS320F280039C C2000 32-bit microcontroller (MCU) from Texas Instruments, which includes a hardware-based delta voltage of resonant capacitor (ΔVCR) comparison, pulse generation and maximum period limitation [4].

In LLC current-mode control, signal Vc comes from the voltage loop compensator, and signal VCR is the voltage sense of the resonant capacitor. A C2000 comparator subsystem module has an internal ramp generator that can automatically provide downsloped compensation to Vc. You just need to set the initial value of the ramp generator; the digital-to-analog converter (DAC) will provide the downsloped VCR limitation (Vc_ramp) based on the slope setting. The comparator subsystem module compares the analog signal of VCR with the sloped limitation, and generates a trigger event (COMPARE_EVT) to trigger enhanced PWM (ePWM) through the ePWM X-bar.

The action qualifier submodule in ePWM receives the compare event from the comparator subsystem and pulls low the high side of PWM (PWMH) in each switching cycle. The configurable logic block then duplicates the same pulse width to the low side of PWM (PWML) after PWMH turns low. After PWML turns low, the configurable logic block generates a synchronous pulse to reset all of the related modules and resets PWMH to high. The process repeats with a new switching cycle.

Besides the compare actions, the time base submodule limits the maximum pulse width of PWMH and PWML, which determines the minimum switching frequency of the LLC converter. If the compare event hasn’t appeared until the timer counts to the maximum setting, the time base submodule will reset the AQ submodule and pull down PWMH, replacing the compare event action from the comparator subsystem module.

This hardware logic forms the inner VCR variation control, which controls the energy delivered to the resonant tank in each switching cycle. You can then design the outer voltage loop compensator, using the traditional interrupt service routine to calculate and refresh the setting of the VCR variation amplitude to Vc.

For a more detailed description of the hybrid hysteretic control logic, see Reference [1].

Figure 3 LLC current-mode control logic with a C2000 MCU where the signal Vc comes from the voltage loop compensator, and the signal VCR is the voltage sense of the resonant capacitor. Source: Texas Instruments

Experimental results

I tested the current-mode control method described here on a 1-kW half-bridge LLC platform with the TMS320F280039C MCU. Figure 4 shows the Bode plot of the voltage loop under a 400 V input and 42 A load, proving that the LLC can achieve 6 kHz of bandwidth with a 50-degree phase margin.

Figure 4 The Bode plot of a current-mode control LLC with a 400 V input and 42 A load. Source: Texas Instruments

Figure 5 compares the load transient between direct frequency control and hybrid hysteretic control with a 400-V input and a load transient from 10 A to 80 A with a 2.5 A/µs slew rate. As you can see, the hybrid hysteretic control current-mode control method can achieve better a load transient response than a traditional direct frequency control LLC.

For more experimental test data and waveforms, see Reference [5].

Figure 5 Load transient with direct frequency control (a) and hybrid hysteretic control (b), from 10 A to 80 A with a 2.5 A/µs slew rate under a 400 VDC input. Green is the primary current; light blue is the output voltage, with DC coupled; purple is the output voltage, with AC coupled; and dark blue is the output current. Source: Texas Instruments

Digital current-mode controlled LLC

The digital current-mode controlled LLC can achieve higher control bandwidth than direct frequency control and hold very low voltage variation during load transition. In N+1 redundancy and parallel applications, this control method can keep the bus voltage within the regulation range during hot swapping or protecting. So, this control method has been widely adopted in data center power and AI server power with this fast response feature and digital programable ability.

Desheng Guo is a system engineer at Texas Instruments, where he is responsible for developing power solutions as part of the power delivery industrial segment. He has created multiple reference designs and is familiar with AC-DC power supply, digital control, and GaN products. He received a master’s degree from the Harbin Institute of Technology in power electronics in 2007, and previously worked for Huawei Technology and Delta Electronics before joining TI.

Related Content

• Power Tips #84: Think outside the LLC series resonant converter box
• Power Tips #117: Measure your LLC resonant tank before testing at full operating conditions
• Power Tips #122: Overview of a planar transformer used in a 1-kW high-density LLC power module
• Power Tips #97: Shape an LLC-SRC gain curve to meet battery charger needs
• Power Tips #92: High-frequency resonant converter design considerations, Part 2

References

1. Hu, Zhiyuan, Yan-Fei Liu, and Paresh C. Sen. “Bang-Bang Charge Control for LLC Resonant Converters.” Published in IEEE Transactions on Power Electronics 30, no. 2, (February 2015): pp. 1093-1108. doi: 10.1109/TPEL.2014.2313130.
2. McDonald, Brent, and Yalong Li. “A novel LLC resonant controller with best-in-class transient performance and low standby power consumption.” Published in 2018 IEEE Applied Power Electronics Conference and Exposition (APEC), San Antonio, Texas, March 4-8, 2018, pp. 489-493. doi: 10.1109/APEC.2018.8341056.
3. “UCC25640x LLC Resonant Controller with Ultra-Low Audible Noise and Standby Power.” Texas Instruments data sheet, literature No. SLUSD90E, February 2021.
4. Li, Aki, Desheng Guo, Peter Luong, and Chen Jiang. “Digital Control Implementation for Hybrid Hysteretic Control LLC Converter.” Texas Instruments application note, literature No. SPRADJ1A, August 2024.
5. Texas Instruments. n.d. “1-kW, 12-V HHC LLC reference design using C2000 real-time microcontroller.” Texas Instruments reference design No. PMP41081. Accessed Jan. 16, 2025.

 

The post Power Tips #137: Implementing LLC current-mode control on the secondary side with a digital controller appeared first on EDN.

In a pre-close trading update for full-year 2024, epiwafer and substrate maker IQE plc of Cardiff, Wales, UK says that it now expects revenue of £118m, exceeding 18 November’s guidance of about £115m. This is up from 2023’s £115.3m...

India’s robotics industry has witnessed tremendous growth in recent years, fueled by the rising demand for automation across various sectors such as manufacturing, healthcare, logistics, and agriculture. With a strong push toward innovation and Make in India initiatives, Indian robotics companies are making significant strides on the global stage. Here’s a look at the top 10 robot manufacturers in India, leading the charge in this transformative industry.

1. GreyOrange

Headquarters: Gurugram

GreyOrange is a global name in robotics and warehouse automation. The company designs and manufactures AI-powered robotic systems such as Autonomous Mobile Robots (AMRs) and Sortation Robots. Their solutions are widely used in e-commerce, retail, and logistics industries. GreyOrange’s innovative approach has positioned it as a pioneer in robotic fulfillment solutions.

2. Hi-Tech Robotic Systemz

Headquarters: Gurugram

Hi-Tech Robotic Systemz specializes in autonomous mobility solutions and industrial automation. The company develops robotic systems for material handling, warehouse automation, and autonomous vehicles. Their expertise in AI and machine learning ensures highly efficient and scalable solutions.

3. Milagrow Robots

Headquarters: Gurugram

Milagrow is a well-known name in consumer robotics, particularly for its floor-cleaning and service robots. The company offers a range of robots for domestic, industrial, and agricultural applications. Their focus on user-friendly designs and affordability has made them a household name in India.

4. Systemantics

Headquarters: Bengaluru

Systemantics focuses on building industrial robots to enhance productivity in manufacturing. The company specializes in articulated robots and SCARA robots, which are used for tasks such as assembly, material handling, and packaging. Their indigenously developed solutions aim to make robotics more accessible to Indian manufacturers.

5. Gridbots

Headquarters: Ahmedabad

Gridbots is a leader in AI and robotics, providing solutions for industries like defense, nuclear, and automotive. The company develops robotic systems for inspection, quality control, and hazardous material handling. Their robots are known for their precision and reliability in complex environments.

6. Asimov Robotics

Headquarters: Kochi

Asimov Robotics focuses on humanoid robots and robotics for healthcare, education, and customer service. The company’s robots are designed for applications such as patient care, training, and visitor assistance. Their innovation in humanoid technology is paving the way for advanced human-robot interaction.

7. ABB India

Headquarters: Bengaluru

A subsidiary of the global automation giant ABB, ABB India is a key player in industrial robotics. The company offers a wide range of robotic solutions for welding, painting, assembly, and material handling. ABB India’s robots are widely used in automotive, electronics, and food processing industries.

8. Fanuc India

Headquarters: Bengaluru

Fanuc India, a subsidiary of Fanuc Corporation, is a market leader in CNC machines and industrial robots. Their robots are used for automation in sectors like automotive, aerospace, and electronics. Known for their reliability and precision, Fanuc India’s robots are a benchmark in industrial automation.

9. Kuka Robotics India

Headquarters: Pune

Kuka Robotics India specializes in industrial robots and automation solutions. Their robots are used for applications such as welding, material handling, and assembly. Kuka’s advanced robotic systems are widely adopted in automotive and manufacturing industries across India.

10. Yaskawa India

Headquarters: Bengaluru

Yaskawa India is a leading provider of robotics and automation solutions. Their offerings include industrial robots for welding, assembly, packaging, and palletizing. Yaskawa’s robots are known for their speed, precision, and adaptability in various industrial processes.

Conclusion

India’s robotics industry is rapidly evolving, driven by the demand for automation and technological advancements. With continued investments in R&D and government support, these top 10 robot manufacturers in India are set to shape the future of automation, not just within the country but globally as well.

The post Top 10 Robot Manufacturers in India appeared first on ELE Times.

RF (radio frequency) chipset firm PseudolithIC Inc of Santa Barbara, CA, USA has raised $6m in a seed funding round led by Entrada Ventures, joined by Foothill Ventures and Uncork Capital...

India’s drone ecosystem has seen remarkable growth in recent years, driven by government initiatives, advancements in technology, and a booming demand for drones across sectors like agriculture, defense, logistics, and surveillance. With the rise of drone manufacturing comes the need for reliable, high-quality components. Here, we take a look at the top 10 drone parts companies in India that are propelling this industry forward.

1. IdeaForge

Headquarters: Mumbai

IdeaForge is one of India’s leading drone manufacturers, specializing in Unmanned Aerial Vehicles (UAVs). Beyond making drones, the company also develops critical components like flight controllers and communication systems. Known for its rugged and high-performance designs, IdeaForge caters to industries like defense, mining, and disaster management.

2. Aero360

Headquarters: Hyderabad

Aero360 has established itself as a key player in providing components like propellers, frames, and motors tailored for high-performance drones. The company emphasizes customizability, allowing clients to design solutions specific to their needs. Aero360’s products are widely used in both commercial and industrial applications.

3. Garuda Aerospace

Headquarters: Chennai

Garuda Aerospace specializes in agricultural and commercial drones but also develops vital parts such as battery systems, GPS modules, and autopilots. The company is heavily involved in precision farming and surveillance, and its in-house development of components ensures high reliability.

4. Asteria Aerospace

Headquarters: Bengaluru

Asteria Aerospace is another significant name in India’s drone landscape, focusing on both hardware and software solutions. They design and manufacture high-grade payload systems, gimbals, and communication modules that cater to sectors like surveillance, mapping, and infrastructure inspection.

5. Omnipresent Robot Tech

Headquarters: Gurgaon

Omnipresent Robot Tech is a prominent provider of drone parts, including sensors, cameras, and propulsion systems. The company has made waves in areas such as industrial inspections, disaster management, and security. They are known for their focus on cutting-edge technology and seamless integration of components.

6. Dhaksha Unmanned Systems

Headquarters: Chennai

Specializing in agricultural drones, Dhaksha Unmanned Systems also produces essential components like spraying mechanisms, power distribution boards, and electronic speed controllers. Their innovative solutions are particularly beneficial for India’s farming community, addressing challenges like crop monitoring and pesticide application.

7. TATA Advanced Systems

Headquarters: Hyderabad

TATA Advanced Systems is a pioneer in the defense and aerospace sector, including the drone industry. The company develops advanced components such as sensors, communication systems, and power solutions, which are integrated into UAVs designed for military and industrial applications.

8. Adani Defence and Aerospace

Headquarters: Ahmedabad

Adani Defence and Aerospace is a key contributor to India’s UAV ecosystem, offering a range of components such as propulsion systems, surveillance payloads, and radar technologies. With a strong focus on defense, their products ensure high performance and reliability in critical missions.

9. BotLab Dynamics

Headquarters: New Delhi

BotLab Dynamics has gained attention for its innovative work in drone light shows and swarming technology. The company also develops parts like communication systems and flight controllers, enabling seamless coordination between multiple UAVs. Their technology is increasingly being used in events, defense, and entertainment.

10. Skylark Drones

Headquarters: Bengaluru

Skylark Drones focuses on enterprise solutions but also contributes to the component supply chain. They produce payload systems, camera mounts, and power solutions for drones used in mining, infrastructure, and surveying. Their ability to deliver scalable solutions has made them a trusted name in the industry.

Conclusion

India’s drone industry is not just limited to manufacturing complete UAVs; it is also creating a robust supply chain of critical components. The top 10 drone parts companies in India, including IdeaForge, Garuda Aerospace, and Asteria Aerospace, are leading the charge by innovating and producing reliable parts that meet diverse industry demands. As the industry continues to evolve, these companies will play a crucial role in defining India’s position in the global drone ecosystem.

The post Top 10 Drone Parts Companies in India appeared first on ELE Times.