Minimally-Supervised Speech Synthesis with Conditional Diffusion Model and Language Model: A Comparative Study of Semantic Coding

Recently, there has been a growing interest in text-to-speech (TTS) methods that can be trained with minimal supervision by combining two types of discrete speech representations and using two sequence-to-sequence tasks to decouple TTS. To address the challenges associated with high dimensionality and waveform distortion in discrete representations, we propose Diff-LM-Speech, which models semantic embeddings into mel-spectrogram based on diffusion models and introduces a prompt encoder structure based on variational autoencoders and prosody bottlenecks to improve prompt representation capabilities. Autoregressive language models often suffer from missing and repeated words, while non-autoregressive frameworks face expression averaging problems due to duration prediction models. To address these issues, we propose Tetra-Diff-Speech, which designs a duration diffusion model to achieve diverse prosodic expressions. While we expect the information content of semantic coding to be between that of text and acoustic coding, existing models extract semantic coding with a lot of redundant information and dimensionality explosion. To verify that semantic coding is not necessary, we propose Tri-Diff-Speech. Experimental results show that our proposed methods outperform baseline methods. We provide a website with audio samples

Natural polysaccharide-based hydrogel bioprinting for articular cartilage repair

Tissue engineering represents a promising approach for impaired articular cartilage tissue regeneration. 3D printed hydrogels have become an emerging tissue engineering strategy because they closely mimic the physical and biochemical characteristics of the extracellular matrix. The formulation of hydrogel ink holds significant importance in attaining a precisely defined scaffold, which could exhibit excellent shape fidelity post-printing. Natural polysaccharide-based hydrogels are a highly promising class of scaffold biomaterials for articular cartilage regeneration in the field of material science and tissue engineering. These hydrogels are particularly advantageous due to their exceptional water absorption capacity, biodegradability, adjustable porosity, and biocompatibility, which closely resemble those of the natural extracellular matrix. This review aims to provide a comprehensive overview of the key characteristics, functions, and research progress in 3D printing technology for natural polysaccharide-based hydrogels. Specifically, this review categorizes the commonly used natural polysaccharide-based hydrogel materials in cartilage tissue engineering, and summarizes the classic literature in this area. In the end, we provide a comprehensive analysis of the challenges and potential applications of natural polysaccharide-based hydrogels in cartilage tissue engineering

Modeling and Control of a Three-Port DC-DC Converter for PV-Battery Systems

This paper presents modeling and decoupled control design for an isolated three-port DC-DC converter (TPC), which interfaces a photovoltaic (PV) panel, a rechargeable battery, and an isolated load. A small signal model is derived from the state-space equations of the TPC. Based on the model, two decoupled controllers are designed to control the power flows of the two sources and the load voltage independently. Experimental studies are performed to verify that the two controllers are capable of regulating the power flows of the PV panel and the battery while maintaining a constant output voltage for the TPC

An Isolated Three-Port Bidirectional DC-DC Converter for Photovoltaic Systems with Energy Storage

This paper proposes a new isolated, three-port, bidirectional, DC-DC converter for simultaneous power management of multiple energy sources. The proposed converter has the advantage of using the least number of switches and soft switching of the main switch, which is realized by using a LCL-resonant circuit. The converter is capable of interfacing sources of different voltage-current characteristics with an isolated load. In this paper, one photovoltaic (PV) panel, one rechargeable battery, and an isolated load are interfaced by the proposed converter. Simulation and experimental results show that the proposed converter is capable of maximum power point tracking control for the PV panel when there is solar radiation and controlling the charge and discharge of the battery when there is surplus energy and power deficiency with respect to the load, respectively

An Isolated Multiport Bidirectional DC-DC Converter for PV-Battery-DC Microgrid Applications

This paper proposes a new isolated, multiport, bidirectional DC-DC converter with the least number of switches for photovoltaic (PV)-battery-DC microgrid applications. The proposed converter is able to perform the maximum power point tracking (MPPT) control for the PV system when solar energy is available as well as control the charge and discharge of the battery with the PV system and the DC microgrid. Simulation and experimental studies are carried out and validate the proposed converter for simultaneous power management of a PV-battery system connected to a DC microgrid

A Single-Switch LCL-Resonant Isolated DC-DC Converter

Isolated converters are desirable in the DC-DC power conversion applications where isolation and/or a large voltage step-up gain is needed. Traditional isolated DC-DC converters either utilize many switches to achieve high efficiency or use few switches which result in low efficiency. This paper proposes a new single-switch isolated DC-DC converter with a LCL-resonant circuit. The proposed isolated DC-DC converter has the advantages of not only using the least number of (i.e., one) switch, but also achieving zero-current switching (ZCS) and zero-voltage switching (ZVS) when the switch is turned on and off, respectively. Experimental results are provided to validate the theoretical analysis and simulation. The proposed converter has achieved the maximum efficiency of 93.5%, which is higher than the corresponding hard-switching converter with a similar topology

An Isolated Three-Port Bidirectional DC-DC Converter for Photovoltaic Systems with Energy Storage

This paper proposes a new isolated, three-port, bidirectional, DC-DC converter for simultaneous power management of multiple energy sources. The proposed converter has the advantage of using the least number of switches and soft switching for the main switch, which is realized by using a LCL-resonant circuit. The converter is capable of interfacing sources of different voltage-current characteristics with a load and/or a DC microgrid. The proposed converter is constructed for simultaneous power management of a photovoltaic (PV) panel, a rechargeable battery, and a load. Simulation and experimental results show that the proposed converter is capable of maximum power point tracking control for the PV panel when there is solar radiation and controlling the charge and discharge of the battery when there is surplus energy and power deficiency with respect to the load, respectively

An Isolated Multiport DC–DC Converter for Simultaneous Power Management of Multiple Different Renewable Energy Sources

This paper proposes a new isolated multiport dc–dc converter for simultaneous power management of multiple renewable energy sources, which can be of different types and capacities. The proposed dc–dc converter only uses one controllable switch in each port to which a source is connected. Therefore, it has the advantages of simple topology and minimum number of power switches. A general topology of the proposed converter is first introduced. Its principle and operation are then analyzed. The proposed converter is applied for simultaneous maximum power point tracking (MPPT) control of a wind/solar hybrid generation system consisting of one wind turbine generator (WTG) and two different photovoltaic (PV) panels. The experimental results are provided to validate the effectiveness of using the proposed converter to achieve MPPT simultaneously for the WTG and both PV panels