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Design of complex multiply-accumulate RISC-V extension for accelerating quantum simulations
(2026) Akopau, Stas
Quantum circuit simulation is an important tool for developing and testing quantum algorithms, but its computational and memory requirements grow exponentially with the number of qubits. A significant part of the computational workload consists of complex-valued matrix–vector operations. Depending on the circuit, the corresponding unitary matrices may contain many zero-valued coefficients that do not contribute to the result. This thesis investigates whether such sparsity can be exploited using specialized hardware. A preliminary analysis of representative quantum circuits was performed to examine the sparsity of their unitary matrices. Based on this motivation, a complex sparse matrix-vector multiplication (SpMV) accelerator was developed using the compressed sparse row (CSR) representation. The architecture consists of vector permutation, parallel complex multiplication, and row accumulation stages. It is intended for use as a coprocessor within an X-HEEP RISC-V system, although the present evaluation considers the standalone accelerator. The accelerator was verified through RTL simulation and synthesized using Cadence Genus with the ASAP7 technology library. Synthetic 8 × 8 complex matrix tiles with densities between 9.4% and 100% were used for evaluation. Timing closure was demonstrated at up to 440 MHz. Reducing the number of non-zero coefficients from 64 to 6 decreased the execution time from 129 to 21 clock cycles, corresponding to a speedup of approximately 6.14× relative to a 100%-dense tile processed by the same accelerator. At 440 MHz, the estimated energy per tile-level operation was reduced by approximately 74%. These results demonstrate that the proposed architecture can exploit matrix sparsity to reduce tile-level execution latency and estimated energy. Complete processor integration and end-to-end quantum-simulation performance remain subjects for future evaluation.
Data-Driven Estimation of Droplet Formation for Conductance Control in Wire-Based Metal Additive Manufacturing
(2026) de Blanche, Harald
This work studies a wire-based metal additive manufacturing process where the distance between the wire and the part being built is controlled indirectly through electrical conductance. The measured conductance is compared to a setpoint, and the wire is raised or lowered depending on whether the conductance is too high or too low. At present, this setpoint is adjusted manually by an operator monitoring the process. The aim of this work is to investigate whether the conductance setpoint can instead be determined automatically, using models that estimate the probability of droplet formation from measured process data. Several approaches are evaluated, including linear models based on PCA as well as convolutional neural networks. The linear models show some correlation with droplet formation but are generally noisy. The convolutional neural network models show promising preliminary results, although further work is required before it can be used as the basis for a control algorithm. In addition, a simple control algorithm based only on observed drops, rather than predictions of future drops, was evaluated. The algorithm was tested in only one experiment, so the results should be considered preliminary. Nevertheless, the results indicate that the algorithm was able to control the process with a similar performance to that of a human operator.
Design Guidelines and Porosity Evolution in Metal Binder Jetting Components
(2026) Paduvan, Ronald Benny
In Metal Binder Jetting (MBJ), a binder is selectively jetted onto a powder bed to form a green part, which is then debound and sintered. Green parts reach only about 53% relative density, so sintering causes large shrinkage, gravity-driven distortion and residual porosity. This thesis studies design guidelines, porosity evolution during sintering and densification by Hot Isostatic Pressing (HIP) for 316L stainless steel printed on a Markforged DM P2500 system. Bridge specimens sintered at 1310 ◦C were used to vary one design parameter at a time. Unsupported span had by far the strongest effect: sag rose from 0.4mm at a 20mm span to 9.1mm at 60 mm. Increasing the top thickness from 3 to 7mm reduced sag from 3.8 to 1.7 mm, a base reduced it from 3.6 to 2.3 mm, and a 20mm inner fillet reduced it by 55 %. Z-oriented bridges sagged about 15% more than flat ones. In pin arrays, pins down to 0.5mm diameter were printed, but at half scale five of six slots retained powder; depowdering rather than printing resolution limited the minimum feature size. Dense and shell cubes were sintered in vacuum at 1250, 1270, 1290 and 1310 ◦C and characterised by Archimedes density measurements and light optical microscopy with image analysis. The relative density of dense specimens rose from 89.0 to 99.0 %, and shell specimens were denser at every temperature. Open porosity fell from 8.7% to below 0.5% already at 1270 ◦C, where closed porosity peaked at 4.7 %. Bulk density alone therefore does not show the open-to-closed porosity transition. The pores became fewer, smaller and rounder, and the share of quasi-circular pores rose from 40 to 70 %. HIP was applied in six conditions between 1070 and 1170 ◦C and 50 and 150MPa. The response depended mainly on the sintered state, not on the HIP temperature or pressure. Dense specimens sintered at 1270 ◦C, with the most closed porosity, went from 5.1% to 0.7–0.9% total porosity. Dense specimens sintered at 1250 ◦C kept 8.0–9.8% porosity because their pores were still open. After HIP, all groups from 1270 ◦C upwards reached about 99% relative density, a level that depends on the assumed theoretical density. Design, sintering temperature and HIP must therefore be chosen together: sintering must first close the pore network before HIP can remove it.
Power Management Strategy for Islanded Operation Using Wind Power, Solar PV, and Battery Storage
(2026) Jinu, Albi; Motty, Abhimanyu
As electricity demand grows and renewable energy becomes a larger part of the power system, maintaining a reliable supply during grid interruptions becomes increasingly important. Microgrids that combine wind power, solar photovoltaics and battery storage can supply local loads independently of the main grid. However, operating these systems in islanded mode requires careful coordination to balance changing generation and demand. This thesis investigates the islanded operation of a wind–solar–battery microgrid based on the Chalmers research wind turbine at Björkö, Sweden. A battery-connected grid-forming converter provides the voltage and frequency reference, allowing wind and solar generation to operate alongside it through grid-following converters. The main objective was to develop a power balance controller and evaluate its ability to work with the grid-forming converter during different operating conditions. The control logic was developed in MATLAB/ Simulink to manage power surpluses and deficits while respecting battery state-of-charge and power limits. When renewable generation exceeds demand, the controller directs the surplus to the battery and curtails generation when necessary. When generation is insufficient, the battery supplies the shortfall, with load shedding used when the available power cannot meet demand. EMTP-RV simulations were then used to evaluate the interaction between the power balance controller and the grid-forming converter. The simulation results demonstrate how coordinated control of generation, storage and demand can support islanded operation within the system’s operating limits. The work provides a basis for developing renewable microgrids that can maintain local electricity supply when disconnected from the main grid.
Arcturus Design och konstruktion av en vektorstyrd modellraket
(2026) Bergstedt, Frode; Eklind, Tilde; Enell, Anton; Gustafsson, Victor; Randerz, Viggo; Richardt, Christian
The goal of the project was to design and build a thrust vector controlled (TVC) model rocket, with an aim to stabilize the rocket with active control. The aim was split into three parts: (1) simulation; (2) static test with free rotation; and (3) free launch. To comply with Swedish laws, the rocket was restricted to maximum weight of 500 g, with a maximum 100 g reserved for propellant. With these design limitations in mind, the rocket body and systems for both the electronics, TVC, and parachute were custom made, with the goal to minimize weight. The designed rocket weighed a total of 499,2 g with propellant. However, parts like the custom flight computer did not work as intended, thus a new makeshift solution was required for launch. After the rocket was designed and built, three static test launches and one live flight were executed. Even though the simulations gave promising results, none of the launches proved successful. This could be due to a discrepancy between simulation and reality. In the end, the goal was achieved, but the aim failed on all three parts, which could have been remedied by a longer research and development phase.