Reconfigurable Power Converter

Updated 5 February 2026

Reconfigurable power converters are systems that use switch matrices to dynamically redistribute converter submodules, improving operational flexibility.
They employ optimal leg sizing and dynamic switching to overcome unbalanced loading and enhance the feasible set of power injections.
Empirical analyses show that strategic reconfiguration can nearly halve hardware requirements while boosting converter capability under varied grid scenarios.

A reconfigurable power converter is defined as a power electronic system that incorporates one or more structural reconfiguration stages—typically implemented using mechanical or solid-state switching matrices—allowing dynamic redistribution of converter submodules (legs, bridges, or entire arms) among multiple output terminals. The overarching objective is to maximize utilization of the installed power electronics and increase the feasible set of power or current injections, tailored to prevailing grid or load conditions. This structural reconfigurability is leveraged to address longstanding utilization bottlenecks, enhance unbalanced loading capability, reduce overall converter cost, and introduce new levers for operational flexibility in both ac/dc and dc-dc power conversion contexts.

1. Reconfiguration Mechanisms and Converter Topologies

In four-wire voltage-source converters (VSCs), conventional topologies consist of four hardwired half-bridge legs, each assigned to a distinct wire (phases a, b, c, neutral). This fixed assignment leads to chronic underutilization under phase-unbalanced loading, with the neutral leg frequently limiting the feasible injection set, even as phase legs are partly idle. The reconfigurable paradigm inserts a low-cost output stage—a switch matrix (mechanical or semiconductor)—enabling an arbitrary number of converter legs, each of per-unit size $\alpha_i$ ( $i = 1, ..., m$ ), to be reallocated on-the-fly among the four output conductors. The selector matrix $B \in \{0,1\}^{4 \times m}$ governs this assignment, enforcing that each leg is connected to one and only one wire at any moment (Deakin et al., 2024).

Key topological classes arising in the literature include:

Conventional fixed-leg 3-leg and 4-leg topologies (denoted UFix(3), UFix(4)).
Uniformly sized reconfigurable topologies (U(m), with $\alpha_i = 1/m$ ).
Optimally sized 4-leg reconfigurations (SOpt. for standalone, IOpt. for interconnected environments).
Idealized fully reconfigurable architectures (continuous allocation of infinitesimal legs; upper-bound performance).

Reconfiguration is not restricted to ac/dc systems: in multiport bidirectional dc-dc converters, such as those designed for hybrid electric vehicles, a small number of legs are reallocated by gating arrangements and duty-cycle control, effecting flexible, port-by-port power routing with fewer switches than conventional isolated converters (Nguyen et al., 2022).

2. Mathematical Formulation of Feasible Set and Capability Charts

The potential of reconfigurable converters is quantified by their feasible region of currents or power injections. Formally, for four-wire VSCs, define:

Phasor current vector $I_d \in \mathbb{C}^4$ , per-wire ratings $I_{\text{max}} \in \mathbb{R}^4$ , and leg sizes $\alpha \in \mathbb{R}^m$ (with $\sum_{i=1}^m \alpha_i = 1$ ).
The selector matrix $B$ allocates leg $i$ to wire $k$ , imposing $|I_d[k]| \leq I_{\max}[k]$ where $I_{\max} = I_{\text{base}} \cdot B\alpha$ .
For fixed output voltages $|V_o|$ , power injection vector $P \in \mathbb{R}^3$ maps to phase currents with a determined neutral current.

The feasible set $\mathcal{P}_{\text{feasible}}$ is: $\Bigl\{ (P_1, P_2, P_3, P_n) \in \mathbb{R}^4 \;\big|\; |I_d[k]| \leq I_{\max}[k],\: k=1\,..\,4; \;\, P_n=0;\;\, P_{\mathrm{tot}} = P_1+P_2+P_3;\;\, P_{\mathrm{tot}} \in [P_{dc, \min}, P_{dc, \max}] \Bigr\}$ for interconnected operation, with $P_{\mathrm{tot}}=0$ in standalone cases (Deakin et al., 2024).

Capability is visualized by capability charts, whose area (in standalone) or volume (interconnected, with dc transfer allowed) is computed via direct integration or grid sampling. The objective is to increase the area/volume for given total converter capacity:

Capability set $\mathcal{C}$ as a geometric domain in $P$ -space
Metrics: Capability-Chart Area (CCA), Capability-Chart Volume (CCV).

For multi-terminal designs, particularly hybrids with multiplexed switch matrices, closed-form expressions exist for capability chart area as a function of leg sizing vector $a$ (Deakin, 2022). The region $\mathcal{C}$ is a planar hexagon (for three-feeder, lossless symmetric designs) with dimensions strictly governed by leg sizing and the reconfiguration pattern.

3. Numerical Performance and Comparative Analysis

Empirical studies consistently show that reconfigurable converters can achieve a substantial increase in usable power-transfer capability per unit converter capacity:

In four-wire VSCs, to match the capability region of an idealized reconfigurable converter, a conventional 4-leg design requires up to 75.3% more total leg capacity (Deakin et al., 2024).
A properly optimized 4-leg topology (SOpt./IOpt.), using optimized leg sizes (greater allocation to the neutral leg), achieves more than 75% of the ideal capability with only 22% additional capacity.
For uniform designs, increasing leg count $m$ (U(m)) initially brings area gains but with diminishing returns (e.g., U(15) only matches SOpt.).

A representative table clarifies the magnitude of these improvements ( $n_A$ = area ratio for standalone, $n_V$ = volume ratio for interconnected):

Design	$n_A$ (standalone)	$n_V$ (interconnected)
Idealized $2_2$	1.000	1.000
Fixed 4-leg UFix(4)	1.578	1.627
Opt. 4-leg SOpt./IOpt.	1.220	1.220
Uniform U(9)	1.456	1.454
Uniform U(15)	1.441	1.428

Thus, reconfiguration can nearly halve the total hardware required for a given operational envelope, particularly under unbalanced or mission-flexible use.

4. Design Space and Optimization Principles

Optimal utilization arises from deliberate non-uniform leg sizing, prioritizing allocation to bottlenecked terminals such as the neutral leg in four-wire networks or highly loaded feeders in multiplexed SOPs. For three-terminal AC-DC-AC converters with reconfigurable multiplexers (Deakin, 2022), the area-maximizing configuration is $(a_1, a_2, a_3) = (0.454,\, 0.364,\, 0.182)$ , yielding a capability area 64% above the conventional equal-leg case.

Reconfigurable designs employ:

Switch matrices for rapid, flexible leg allocation
Uniform or hierarchy-based sizing vectors ( $a$ ) for converter legs, optimized via nonlinear programs maximizing capability area/volume
Closed-form geometric and algebraic analysis to determine power-flow limits and achievable region
In multiport applications, mixed-integer optimization over mission profiles reveals that electrical cardinality constraints (number of concurrently active legs) can allow substantial cost reductions with only incremental loss of grid-service capability (Deakin, 2023).

5. System-Level Implications and Implementation Considerations

The reconfigurable paradigm enables:

Dynamic response to phase unbalance: By reallocating leg capacity according to time-varying unbalance, utilization limits imposed by the neutral path (or weakest leg) are overcome, minimizing installed kVA rating for a required flexibility.
Cost-efficient Soft Open Points (SOP): In distribution systems, multiplexed converter legs with judicious sizing enable more than a twofold increase in real/reactive capability for the same hardware cost, with cost reductions of 15–30% for equivalent service (Deakin, 2023).
Hierarchy of design trade-offs: Design can be tuned for maximum area (overall flexibility), maximum power-transfer to selected feeders, or minimized converter block-count by analyzing the capability chart metric appropriate to the use-case.
Robustness to operating constraints: DC-side operational constraints (such as $P_{\mathrm{tot}} \neq 0$ ) introduce non-convexities in the feasible set, requiring careful mission-profile analysis. For mission profiles where not all ports are maximally used simultaneously, converter topologies with lower cardinality (fewer legs, enhanced by reconfigurable switches) can service nearly all required power flows (Deakin, 2023).

Optimal sizing often surpasses brute-force increase of leg count; a 4-leg SOpt configuration is more efficient than a uniform 9–15 leg design, underscoring the primacy of allocation strategy over raw redundancy.

6. Practical Applications and Future Extensions

Reconfigurable power converters see deployment in:

Low-voltage unbalanced distribution networks (four-wire, multi-terminal VSCs) for loss minimization and neutral-current mitigation.
Flexible soft open points and multiport power routers, where system-level topology may change hour-to-hour or feeder-to-feeder.
Grid support devices requiring dynamic adaptation to changing mission profiles or contingencies.

Emergent research directions involve analytical and algorithmic frameworks for automated reconfigurable topology synthesis (e.g., AI-guided search (Gao et al., 29 Jan 2026)), time-series mission profiling for converter design (Deakin, 2023), and integration into holistic distribution system operation and planning.

7. Key Insights and Current Research Consensus

A minimal reconfiguration stage (well-designed switch matrix) can make a modestly redundant four-wire converter nearly as flexible as an idealized, fully reconfigurable device.
Optimal leg sizing, especially favoring over-dimensioned neutral or weakly utilized paths, dominates uniform approaches in all relevant performance metrics.
Reconfiguration is most valuable where phase or feeder loadings are highly dynamic, and is less impactful in strictly balanced, stationary settings.
The cost, complexity, and operational risk of reconfiguration (including switch failure modes and selector logic limits) are outweighed by kVA, CAPEX, and utilization improvements for most modern LV/MV distribution applications (Deakin et al., 2024, Deakin, 2023).

Reconfigurable power converters thus represent a mature, quantitatively grounded design response to the needs of flexible, resilient, and cost-efficient electric power systems in the presence of pervasive load and source unbalance, with clear analytical and empirical justification across multiple research programs and system scenarios.