SST DC Microgrid Deep Dive: How 10+1 Ports Unify PV, Storage, Charging & Hydrogen with "Direct-Flexible" Integration

1. Industry Background & Pain Point Analysis

1.1 Industry Background

Overseas industrial parks, islands, and commercial and industrial users increasingly demand energy that is "self-generated, self-consumed, low-carbon, and reliable." Traditional AC microgrids suffer from multi-stage AC/DC conversion losses, complex grid-connected/islanded switching, and difficulties integrating multiple energy sources (PV, storage, charging, hydrogen). DC microgrids, which use a common DC bus to unify diverse energy carriers, have become the mainstream technical route for zero-carbon parks.

1.2 Four Major Pain Points of Traditional AC Microgrids

1.3 Core Differences: Traditional AC vs. SST DC Microgrid (Physical Essence)

Physical root cause: The DC bus enables PV, storage, charging, and hydrogen to couple directly in DC, avoiding multiple AC/DC conversions—this is the fundamental physical basis for overall microgrid efficiency improvement and the first-principle differentiator of this solution over traditional approaches.

2. Solution Overview & Value Proposition

2.1 Solution Definition (BLUF)

This solution features the SST solid-state transformer as the core and a 10+1-port DC router as the backbone, building a "PV-Storage-Charging-Hydrogen direct-flexible" commercial complex DC microgrid: PV, storage, charging, hydrogen, and building loads flexibly access a unified DC bus, with only one AC conversion at the grid interface. Overall plant efficiency reaches 94.5%–97.5% (3–5 percentage points higher than AC solutions), with grid/island switching <20 ms.

Benchmark project: Amsterdam, Netherlands — "PV-Storage-Charging-Hydrogen direct-flexible" commercial complex demonstration project (one of Europe's first, 10+1-port DC networking).

2.2 Core Value Proposition

3. System Architecture Design

3.1 System Topology (Layered Breakdown)

SST DC Router (10+1 ports) Port Planning:

• Source ports: PV input (DC), storage (DC), grid connection (AC — the sole AC interface)

• Load ports: Charging piles (DC), hydrogen production (DC), building loads (DC/AC optional)

• Routing core: SST DC router with full-port power controllability

• Management layer: EMS (Energy Management System) + microgrid controller for unified scheduling and black-start management

3.2 Seamless Grid/Island Switching Principle

Inherent isolation via DC networking: The SST router implements smooth mode switching through cascaded control of power outer loop and voltage inner loop, with switching time <20 ms (within one cycle), no transient impact, and no downtime. In island mode, the storage provides bus voltage support; in grid-connected mode, the grid interface maintains power balance. This capability is the core reliability enabler for overseas island and park applications.

4. Core Equipment & Technical Parameters

SST DC Router Core Parameters (10+1 ports, series configurations):

5. Technical Highlights & In-Depth Physical Principle Analysis

5.1 Highlight 1: Multi-Port DC Networking

Physical principle: PV, storage, charging, and hydrogen are directly DC-coupled through the SST router's multiple ports, eliminating multiple conversions.
Quantified benefit: Source-load direct connection eliminates 2–4 conversion stages; overall efficiency 94.5%–97.5%, 3–5 p.p. higher than AC solutions; THD <1%, no additional filtering required.

5.2 Highlight 2: Seamless Grid/Island Switching

Physical principle: Inherent DC bus isolation, plus power-voltage cascaded control, enables transient-free switching.
Quantified benefit: Switching time <20 ms (within one cycle); reliable in both island and grid-connected modes; no downtime or power interruption during transitions.

5.3 Highlight 3: Multi-Energy Integration & Plug-and-Play

Physical principle: PV, storage, charging, and hydrogen are unified on a single DC bus with modular ports.
Quantified benefit: Simplified system and easy expansion—new sources/loads connect plug-and-play; capacity scales modularly; single-port faults are rapidly bypassed via N+X redundancy, ensuring availability ≥99.9%.

6. Economic Comparison with Traditional Solutions

Note: Loss figures are based on "single AC/DC conversion 1%–3% (typical for SiC inverters); traditional multi-stage cumulative 2%–6%." Detailed economics should be calculated based on project scale, local electricity tariffs, and construction costs.

7. Benchmark Project Evidence

Evidence chain note: "One of Europe's first" is based on public-case references; bidding stage can provide project commissioning date, system capacity, and third-party test reports for substantiation.

8. Technical Standards, Redundancy & Safety

8.1 Technical Standards & Compliance

8.2 Redundancy Architecture

N+X intelligent online redundancy: dual power supplies + dual-controller hot standby; faulty IGBT auto-bypass; single-port faults do not propagate; system availability ≥99.9%.

8.3 DC Safety

DC arcs have no natural zero-crossing and are persistent—the solution deploys three defense lines: ① Fast solid-state isolation logic per IEC 60947-2 Annex P (arc clearing time <25 μs); ② DC-side insulation online monitoring (real-time insulation resistance/leakage current alarms); ③ Port-level fault isolation and fast arc extinction to prevent single-point fault propagation. Overseas project delivery includes a safety design description and protection setting scheme.

9. Delivery & Services

• Modular DC router: Factory prefabricated, complete-unit shipment, and rapid on-site installation;

• Overseas localized delivery: Supports destination-country standard adaptation and local certification assistance;

• Full-lifecycle remote O&M: EMS cloud monitoring + OTA upgrades + fault self-diagnosis + SOH online assessment.