What this page solves

PCS for ESS is the bidirectional power interface between the battery or DC bus and the grid or microgrid. It controls charging and discharging power, enforces grid-synchronization, and provides the protection layer that keeps high-power devices within safe operating limits.

On the DC side, the PCS connects to battery racks, shared DC buses or supercapacitor modules. On the AC or higher-level DC side, it ties into the utility grid, microgrids or large EV fast-charging buses. In many projects the PCS becomes the only controllable point where energy can move both into and out of an energy storage system.

A well-designed PCS must protect IGBT or SiC power devices during fast transients, deliver low-latency current feedback into control loops, supervise the DC-link so capacitors survive worst-case conditions and satisfy the interconnection rules of IEEE 1547 and local grid codes.

• Clarifies when a dedicated bidirectional PCS is required instead of a simple inverter.
• Shows how the PCS sits between battery racks, DC buses, grids and DC fast-charging loads.
• Highlights the protection and feedback roles that keep the system safe and controllable.
• Prepares later sections on gate drivers, isolated current sensing and grid-sync AFEs.

Use this page as a reference whenever a PCS must move energy both into and out of an energy storage system while staying compliant with grid and safety requirements.

System context & energy-flow map

In a real energy storage project, the PCS does not stand alone. It sits between battery racks and their pack BMS on the DC side and the grid-facing world managed by the EMS or site controller on the AC or higher-level DC side. This section shows where the PCS fits in that chain and how energy and control signals move around it.

1. Battery racks and pack BMS – manage cell-level voltages, temperatures, balancing and state-of-charge, and define safe operating limits.
2. DC bus or intermediate DC/DC stages – aggregate multiple racks and shape the DC voltage presented to the PCS.
3. Bidirectional PCS – converts between the DC domain and the AC grid or local AC buses, enforces current and voltage limits and implements grid codes.
4. Step-up transformer and switchgear – match voltage levels and connect the PCS to feeders, distribution buses or the utility.
5. EMS / site controller – decides when the PCS should charge, discharge or provide ancillary services, and at what setpoints.

Roles of BMS, PCS and EMS

• BMS – focuses on cells and modules, monitoring voltages, temperatures and health, balancing cells and publishing safe operating windows to the rest of the system.
• PCS – focuses on power conversion and grid interconnection, implementing current and voltage control loops, protections and grid-synchronization.
• EMS – focuses on energy and business logic, deciding charge and discharge schedules and setpoints while coordinating multiple PCS units and other assets.

Cell-level sensing and balancing are covered in the Pack BMS and BMU/CMU pages, while plant-level dispatch and market logic belong to the ESS EMS edge controller topics. This page stays focused on the PCS itself and its immediate interfaces.

Power-stage topologies & operating modes

Power-stage topology determines the DC-link voltage class, the voltage stress on power devices and the level of dv/dt and common-mode noise that the rest of the system must tolerate. It also sets how many switches and gate-driver channels are required and how complex the modulation strategy becomes. Choosing the right topology early in a PCS design avoids later compromises in efficiency, device selection and compliance with grid codes.

Topology families for an ESS PCS

Another structural choice is whether the PCS presents a three-wire or four-wire interface to the AC side. Supporting a neutral conductor enables direct connection to some distribution systems and unbalanced loads, but adds current paths and sensing requirements that must be reflected in the protection and control design.

Operating modes for a bidirectional PCS

Once a topology is chosen, operating modes determine how the PCS is driven in daily operation. Charge, discharge, reactive support and islanded operation each place slightly different demands on gate driving, current sensing and DC-link protection.

Charge mode (grid → DC)

• Controls power transfer from the grid or AC bus into the DC link and battery racks, respecting power, current and voltage limits defined by the BMS.
• Must keep power factor and current harmonics within grid-code limits while handling grid voltage swings.
• Requires fast overcurrent detection and robust gate-drive behaviour during grid faults and battery-side disturbances.

Discharge mode (DC → grid)

• Delivers active power from the ESS into the grid or local AC bus following setpoints from the EMS.
• Must ride through certain grid disturbances and apply fault ride-through profiles where required.
• Increases sensitivity to dv/dt and device reverse-current behaviour, pushing gate drivers toward negative bias, accurate dead time and well-controlled turn-off slopes.

Reactive power and power-factor control

• Operates with low or zero net active power while providing reactive support and power-factor correction.
• Keeps device currents and thermal loading within limits even when DC-link energy changes slowly.
• Relies on precise current sensing and stable modulation, but still benefits from the same gate-drive protections as in active power modes.

Black start and islanded microgrid modes

• Provide a voltage and frequency reference for a microgrid when the utility grid is not present or temporarily disconnected.
• Require carefully sequenced start-up and shut-down procedures to protect the DC link and power devices.
• Demand close coordination between gate drivers, current sensing, DC-link supervision and EMS start-up logic.

Bidirectional operation does not only reverse the direction of energy flow. It also changes current directions, switching stresses and protection priorities, which must be reflected in topology selection, gate-driving schemes and sensing architectures.

Bidirectional gate-driver design & protections

In a bidirectional PCS, the gate driver for each IGBT or SiC switch must handle large current swings in both directions, fast transients and strict grid-code requirements. Turn-on and turn-off behaviour, fault detection, isolated supplies and external interlocks all combine into the protection chain that keeps the power stage and DC link safe.

Turn-on and turn-off control for bidirectional current

Charge and discharge modes change the direction of current in each phase leg, so dead time and gate timing must be tuned for both directions. Too little dead time raises shoot-through risk, while excessive dead time increases diode conduction and switching losses. Higher dv/dt in ESS PCS applications also makes Miller-induced false turn-on more likely, especially when fast wide-bandgap devices are used.

• Tight, well-characterised dead time is required to balance efficiency and safety across all operating modes.
• Negative gate bias and integrated or external Miller clamps help resist false turn-on during high dv/dt transitions.
• Gate resistance values and layout must support both smooth turn-on and controlled turn-off to limit EMI and overvoltage.

Fast fault detection and soft shutdown

Short circuits, overloads and abnormal operating points must be detected quickly to prevent damage to power devices and the DC link. DESAT detection is widely used to sense a rising V_CE or V_DS as an indicator of excessive current. The blanking time, filtering and threshold settings around this function determine how reliably the driver distinguishes between normal switching and true faults.

When a fault is detected, a soft shutdown sequence reduces the gate drive in a controlled way instead of snapping the device off instantly. This limits di/dt and the overvoltage seen across the DC link and stray inductances, while still forcing current down quickly enough to protect the device. Thermal information from NTC sensors or other temperature monitors can be integrated into driver decisions to derate or shorten allowable fault durations at high temperature.

Isolated supplies and layout notes

Each high-side and low-side switch in a phase leg requires a clean, isolated supply for its gate driver. Three-level topologies increase the number of switches and therefore the number of isolated supplies and channels. The placement of each DC/DC converter and the routing of its outputs strongly influence gate loop inductance, noise coupling and the effective dv/dt seen by the isolation barrier.

• Short, tight gate loops with a clear return path reduce ringing and improve timing repeatability.
• Decoupling capacitors should be placed close to each driver supply, with attention to common-mode currents.
• Isolation devices must withstand the common-mode dv/dt present in the chosen topology and switching pattern.

Safety chain layering around the driver

The gate driver sits in the middle of a wider safety chain. It provides the fastest local reaction to device faults, while the controller and external interlocks add slower but more global protections. Each layer should be able to act independently so that a single fault in firmware or a communication link does not remove all protection.

• Driver-level protections such as DESAT, undervoltage lockout and soft shutdown act locally on a single device or phase leg with minimal delay.
• The controller can disable PWM outputs, reduce current limits and log detailed diagnostics when faults are reported by one or more drivers.
• External interlock chains from HV disconnect units, emergency stops or safety relays can force drivers or their supplies into a safe state, independent of firmware.

Combining these layers allows a PCS to survive device-level faults, grid disturbances and control failures with predictable behaviour, which is essential for high-power ESS deployments.

Isolated ΣΔ current-sensing chain

In high-power PCS designs, isolated sigma-delta (ΣΔ) modulators are widely used for current sensing. The combination of shunt resistors and ΣΔ modulators handles high common-mode voltages, provides sufficient bandwidth for fast PWM and exposes a robust digital interface to the controller, which simplifies routing, accuracy budgeting and long-term stability.

Why isolated ΣΔ sensing fits high-power PCS

• Isolation and common-mode robustness. The modulator sits on the high-voltage side with the shunt and tolerates several hundred volts of common-mode swing, while the digital bitstream crosses the isolation barrier with high noise immunity.
• Bandwidth for fast PWM. Properly configured ΣΔ chains support the kHz switching frequencies used in bidirectional PCS, while still delivering the resolution needed for FOC and current limiting.
• Digital interface and channel matching. Digital outputs connect directly to MCU or DSP interfaces or to dedicated ΣΔ filter blocks, improving channel-to-channel consistency and easing layout around noisy power stages.

From sensor element to control loop

A typical isolated ΣΔ sensing chain for PCS current feedback can be viewed as a sequence of blocks:

• Sensor element: a shunt resistor, current transformer or Rogowski coil generates a proportional signal.
• Isolated ΣΔ modulator: converts the analog signal into a high-frequency bitstream on the high-voltage side.
• Digital filter / decimator: sinc or similar filters reconstruct the current value at a suitable update rate for control loops.
• Control and protection logic: FOC, current limiters and diagnostics consume the filtered current values and fault flags.

Where to measure: phase currents vs DC-link current

PCS designs must decide where current is measured and how many channels are justified. Phase-current sensing and DC-link sensing provide different benefits and are often combined in higher power systems.

Phase-current sensing

• Provides direct measurements for FOC or vector control, enabling accurate torque and flux regulation in all four quadrants.
• Captures unbalanced loading between phases and supports detailed diagnostics of each leg.
• Increases the number of sensing channels and isolated ΣΔ devices, which affects cost and layout effort.

DC-link current sensing

• Uses fewer sensors and is straightforward to place, making it attractive for monitoring overall power and energy flow.
• Works well for protection, power limiting and state-of-charge estimation in combination with the BMS.
• Provides limited visibility into phase imbalance and harmonic content, so it is often paired with at least one phase-current channel in demanding applications.

Filtering, delay and fast protection paths

The bitstream from a ΣΔ modulator is usually processed by a sincⁿ digital filter and a decimator. Higher filter order and oversampling provide better noise performance, but also increase latency and reduce the maximum achievable control bandwidth. Controller design must balance current-loop speed against noise and quantization effects.

For protection, relying only on filtered digital values can be too slow in the event of a hard short. Many PCS designs therefore use two parallel paths: a filtered digital path for FOC and current limiting, and a fast analog comparator path for µs-scale overcurrent detection that feeds gate-driver or hardware trip inputs.

Combining an isolated ΣΔ chain for precise control with fast comparator-based protection allows the PCS to meet efficiency, dynamic performance and safety requirements at the same time.

DC-link monitoring & protection

The DC link behaves like the heart of a PCS, storing and releasing energy between the battery or DC bus and the AC grid. Overvoltage, undervoltage, excessive ripple or capacitor stress can shorten lifetime or trigger catastrophic failures, so DC-link voltage, temperature and balance must be monitored and linked to fast protective actions.

What to monitor on the DC link

• DC-link voltage. Normal operating range, overvoltage margins and undervoltage thresholds must be defined for each operating mode, including black start and islanded operation.
• Capacitor temperature. Electrolytic and film capacitors are sensitive to temperature; monitoring case or hotspot temperatures via NTCs enables lifetime prediction and derating.
• Segment voltages and imbalance. In series or segmented capacitor banks, voltage imbalance can indicate degradation or leakage, and may lead to local overvoltage if not detected early.

Protective actions linked to DC-link behaviour

DC-link measurements do not only feed supervisory diagnostics. They also drive real-time actions such as pre-charge, controlled discharge and fast hardware trips.

Pre-charge control

• Uses a dedicated resistor and contactor path to charge the DC-link capacitors gradually before the main contactor closes, avoiding inrush currents that stress devices and fuses.
• Monitors the DC-link voltage ramp; deviations from the expected rise profile indicate wiring, contactor or supply issues that must be handled before proceeding.

Controlled discharge

• Brings the DC-link voltage down to a safe level after shutdown or a fault, using dedicated discharge resistors or controlled operation of the power stage.
• Ensures residual voltage remains below safety thresholds within the time limits required by standards and internal procedures.

Hardware UV / OV comparators

• Provide independent undervoltage and overvoltage thresholds alongside any ADC-based measurements.
• Overvoltage comparators can command immediate gate-driver shutdown or request HV disconnect actions, protecting capacitors and power devices from excessive stress.
• Undervoltage comparators prevent operation in regions where control may become unstable or insufficient to satisfy grid-code requirements.

Interface to disconnect and pre-charge functions

• DC-link monitoring modules send “pre-charge complete”, “overvoltage” and “undervoltage” signals to contactor, pre-charge and disconnect controllers.
• These interfaces allow higher-level safety logic to coordinate contactor states without duplicating sensing hardware.

Sensing IC and AFE options for DC-link monitoring

DC-link monitoring can be implemented using several classes of analog front-end and monitoring devices. Each approach offers different trade-offs in accuracy, isolation and integration.

• High-voltage divider + isolated amplifier. A resistor divider scales the DC-link voltage, and an isolated amplifier or sigma-delta modulator transfers this signal to the control side with defined bandwidth and CMR performance.
• Dedicated DC-link sensing amplifiers. Specialized amplifiers include input networks tailored for high-voltage sensing, offering improved linearity, temperature performance and simplified design.
• Monitor ICs with integrated comparators. Monitoring ICs combine measurement outputs with UV/OV comparators, exposing both analog or digital voltage readings and direct fault signals for fast hardware actions.

Failure modes and mitigation on the DC link

Treating the DC link as a monitored and actively protected subsystem increases PCS robustness and makes field behaviour more predictable across operating modes and grid events.

Grid-sync AFEs & power-quality hooks

Grid-tied PCS must sense three-phase voltages and currents accurately, lock onto grid angle and frequency, and supervise basic power-quality limits before injecting or absorbing power. Front-end AFEs scale and isolate grid signals so that PLL and control algorithms can synchronize safely across different voltage levels and operating modes.

Voltage AFE for grid synchronization

The voltage AFE converts 400/480/690 Vac line or phase voltages into signals that are safe for ADC inputs while maintaining isolation and bandwidth for grid synchronization and power-quality measurements.

• Input range and topology. Designs combine high-voltage dividers, protective components and either voltage transformers or isolated amplifiers to cover 400/480/690 Vac grids with the required insulation and creepage.
• Surge protection. MOVs, gas discharge tubes and RC networks limit surge energy, while series resistors and clamps protect the AFE inputs from lightning and switching transients.
• Common-mode rejection. Differential front ends and high CMRR amplifiers reduce the impact of dv/dt from the PCS power stage and external noise on voltage measurements used by PLL and power-quality functions.
• Bandwidth. Bandwidth is chosen to capture the 50/60 Hz fundamental, frequency variations and a limited harmonic range sufficient for THD and unbalance detection without amplifying high-frequency switching noise unnecessarily.

Current AFE for grid-side power and power-quality feedback

Grid-side currents provide the information needed for active and reactive power control, power-factor adjustment and current harmonic monitoring. These measurements typically reuse the isolated ΣΔ or other current-sensing chains described earlier in the context of PCS power stages.

• Phase versus line currents. Three-phase, three-wire and four-wire systems require appropriate combinations of phase and line current sensors so that instantaneous power and harmonic components can be reconstructed accurately.
• Sampling bandwidth and resolution. The current AFE and ΣΔ configuration must support both current-loop dynamics and harmonic content analysis, while maintaining phase alignment with voltage measurements for precise power-factor and reactive power calculations.
• Protection linkage. Grid-side current measurements support not only synchronization and power-quality supervision but also overcurrent, reverse power and imbalance protections, in combination with fast comparator or desaturation circuits.

PLL and synchronization thresholds

The phase-locked loop (PLL) uses the sensed grid voltages to estimate phase angle and frequency. This synchronized reference underpins vector control, power-factor regulation and grid-code compliance.

• PLL algorithms typically operate in the αβ or dq frame, driving the quadrature component of grid voltage toward zero and producing a stable angle and frequency estimate even under moderate distortion.
• Synchronization thresholds define allowable voltage, frequency and phase-angle deviations before the PCS can connect, remain connected or must disconnect from the grid.
• Parameters such as rate-of-change-of-frequency (ROCOF), under/over-voltage windows and phase jumps feed anti-islanding and fault-handling logic in higher-level microgrid or protection functions.

Power-quality and anti-islanding hooks from the PCS side

Beyond basic synchronization, grid measurements provide hooks for power-quality supervision and anti-islanding decisions. PCS controllers derive a set of metrics that can be acted on locally or forwarded to microgrid and protection functions.

• Harmonics and THD. Voltage and current spectra around the fundamental are used to track total harmonic distortion and individual harmonic magnitudes, ensuring that PCS injections meet grid-code and site-specific limits.
• Power factor and reactive power. Instantaneous power calculations and dq components of voltage and current support precise control of power factor, reactive power and voltage support modes at the PCC.
• Unbalance detection. Monitoring per-phase voltage magnitude and angle highlights unbalance conditions that may require derating, alarms or handover to dedicated microgrid or islanding control functions.

Typical grid-connection sequence

A structured synchronization and ramp-up sequence improves reliability and simplifies compliance with connection requirements. A typical sequence is:

1. Measure grid voltages and check that amplitude, frequency and unbalance are within permitted windows.
2. Run the PLL until phase angle and frequency estimates converge and remain stable for a defined dwell time.
3. Inject a small amount of power and verify that current waveforms, harmonics and protection signals behave as expected.
4. Ramp active and reactive power toward the target operating point while continuing to supervise power-quality and synchronization thresholds.

Well-designed grid-sensing AFEs and synchronization logic allow the PCS to connect confidently to weak, distorted or dynamically changing grids while maintaining power-quality commitments.

Control, safety & redundancy architecture inside PCS

Megawatt-class PCS operate at the intersection of high power, strict grid codes and demanding availability targets. A layered architecture separates real-time control, supervision and hardware safety, and uses redundancy and diagnostics to keep the system safe and maintainable over long service lifetimes.

Control core: DSP, MCU and FPGA roles

The control core typically combines a real-time controller, one or more supervision MCUs and optional programmable logic. Clear partitioning reduces complexity and supports scalability across different power ratings and grid standards.

• Main control DSP / MCU. Executes current and voltage control loops, PLL, power-factor and reactive power control, and ramps during grid connection, with deterministic timing aligned to PWM cycles.
• Auxiliary MCU. Manages system state machines, user or HMI interfaces, local data logging and higher-level communication stacks toward EMS, gateways and service tools.
• FPGA / CPLD. Handles timing-critical PWM generation, ΣΔ sampling alignment, protection aggregation and high-speed interlocking where nanosecond-level determinism is required.

A simple summary is: the DSP or main MCU runs real-time control, the auxiliary MCU handles supervision and communication, and the FPGA or CPLD enforces tight timing and parallelism around the power stage.

Safety chains from software limits to hardwired interlocks

Safety in PCS is realised as a chain of layers, from software limiters through hardwired interlocks down to the self-protection features of gate drivers and power devices. Each layer is designed to react within a defined time and to take appropriate action when the layer above fails or reacts too slowly.

• Software protections. Control firmware enforces configurable limits on current, voltage, power, temperature and ramp rates, first attempting derating and controlled shutdown before triggering hard trips where standards require.
• Hardwired safety I/O and interlocks. Emergency stop loops, protection relays and safety PLC outputs are wired directly to contactor coils, breaker shunt trips and gate-driver enable inputs, so that safety actions remain effective even if the main controller is halted or misbehaving.
• Gate-driver and power-device self-protection. Desaturation detection, undervoltage lockout, local overtemperature and fast short-circuit responses provide the innermost protection layer at microsecond time scales, preventing device destruction and limiting fault energy.

If firmware-based protections fail or respond too slowly, hardwired interlocks are expected to force the PCS into a defined safe state. If interlocks are unavailable or blocked, gate-driver self-protection still intervenes locally at the switch level.

Redundancy, self-test and diagnostic hooks

Diagnostic and redundancy features help large PCS platforms meet uptime and serviceability objectives. Built-in tests and logging allow operators to detect degradation early and to reconstruct events after a trip.

• Watchdogs and self-test. Independent watchdogs for main and auxiliary controllers supervise firmware execution. Power-on self-tests cover memory integrity, peripherals, sensor paths and communication links before allowing the PCS to enter a power-producing state.
• Startup safety checks. DC-link voltage and pre-charge behaviour, sensor plausibility, insulation monitors, contactor feedbacks and grid-sense signals are verified at startup to avoid energising into unsafe conditions.
• Event logging and health metrics. Key operating values and fault information are captured around trips and abnormal events, and summary statistics are exposed to telemetry and asset-health functions for long-term trend analysis.

Internal communication paths

Communication across the PCS connects the control core, AFEs and external systems. Real-time control paths use low-latency links, while supervisory communication focuses on robustness and interoperability.

• Upward communication uses CAN, industrial Ethernet, serial links or fibre to exchange commands and status with EMS, site gateways or remote monitoring systems.
• Downward communication to AFEs, ΣΔ modulators and other mixed-signal devices relies on isolated SPI, LVDS, bitstreams and GPIOs to move measurements and control information across isolation barriers.
• Separate bandwidth and priority classes for real-time control traffic and slower supervisory data help maintain deterministic control behaviour under heavy communication loads.

Viewing PCS as a stack of control, safety and diagnostic layers makes it easier to allocate functions to the right devices, design credible fault responses and support grid and safety standards over the full lifetime of an ESS installation.

Application mini-stories (front-of-meter & behind-the-meter)

These mini-stories show how PCS blocks come together in real projects. One example sits in front of the meter at utility scale, the other behind the meter alongside DC fast charging. Each highlights how gate drivers, isolated current sensing, DC-link monitoring and grid-sensing AFEs are combined with BMS and EMS functions.

Design checklist & IC mapping for PCS in ESS

Use this section as a pre-power-up review and as a quick map from PCS design blocks to IC categories. Each checklist group links back to earlier sections on topology, gate drivers, current sensing, DC-link monitoring, grid synchronization and control architecture.

Design checklist before lab power-up

Power stage & topology (→ H2-3 · pcs-topologies-modes)

• The choice between two-level and three-level NPC/ANPC/T-type topologies matches DC-bus voltage, power rating and grid-code constraints.
• IGBT or SiC module voltage, current and SOA ratings cover worst-case fault and overload conditions with adequate margin.
• Neutral-point balancing and capacitor voltage sharing are addressed in both hardware and control algorithms for three-level designs.
• Output filter parameters (LCL or variants) meet harmonic and stability requirements for the targeted grid impedance range.
• Parallel module and redundancy strategy (for example, N+1 PCS units) is validated under single-module outage and unbalanced loading.

Gate drivers & protection thresholds (→ H2-4 · pcs-bidirectional-gate-drivers)

• Every switch has an isolated gate driver and supply with appropriate insulation, creepage and clearances for the DC-bus voltage.
• Gate resistance, negative gate bias and Miller clamp options are tuned for bidirectional current, short circuits and EMI limits.
• DESAT, overcurrent and overtemperature thresholds align with device data sheets, grid codes and mechanical limits of transformers and filters.
• Fast shut-down paths are defined and tested, from local gate-driver actions through hardware interlocks to firmware-level shutdown.
• Gate-driver power-on sequencing and UVLO behaviour are verified so that no unintended turn-on can occur.

Current sensing & DC-link sensing (→ H2-5 · pcs-isolated-sd-current-sensing, H2-6 · pcs-dc-link-monitoring-protection)

• Phase-current and/or DC-link measurement points are selected to satisfy both control-loop and protection requirements.
• Isolated ΣΔ modulators or amplifiers provide sufficient dynamic range, bandwidth and latency for the chosen PWM frequency and control algorithms.
• DC-link voltage measurement is accurate and fast enough to support OV/UV protection, pre-charge control and ride-through logic.
• DC-link capacitor temperature and leakage or imbalance monitoring are implemented and connected to maintenance strategies.
• Fast analogue comparator paths cover the most critical overcurrent and overvoltage events in parallel with digital ΣΔ processing.

Grid sync, protection & standards (→ H2-7 · pcs-grid-sync-power-quality)

• Voltage and current AFEs support the target grid voltage level, insulation class, common-mode rejection and harmonic bandwidth.
• PLL behaviour is validated under distortion, unbalance and frequency excursions representative of the intended grid connection.
• Connect and disconnect thresholds for voltage, frequency, ROCOF and phase jumps match the applicable grid code or local interconnection standard.
• Harmonic, THD and power-factor targets and associated PCS actions (derating, alarms, trips) are fully defined.
• Anti-islanding logic is consistent with microgrid and protection functions and uses the same measurement and event flags.

Control, safety & redundancy (→ H2-8 · pcs-control-safety-architecture)

• Roles of main control DSP/MCU, auxiliary MCU and FPGA/CPLD are clearly partitioned and documented, including failure modes.
• Software and hardware safety chains are layered, and test cases cover e-stop, protection relay trips, single-point failures and communication loss.
• Watchdogs, self-test routines and power-on checks are implemented and verified on the target hardware.
• All safety-related I/O, including safety PLC outputs, interlocks, contactor feedbacks and auxiliary supplies, have been functionally tested.
• Critical fault paths, such as loss of gate-driver power or sensor disconnection, have predictable derating or shutdown behaviour.

Thermal & mechanical integration

• Thermal paths from power modules, inductors, transformers and DC-link capacitors to heatsinks or cooling systems have been analysed.
• Temperature sensor placement covers known hotspots and is integrated into protection and derating logic.
• Grounding, shielding and routing take high dv/dt effects into account and keep control and sensing lines away from noisy power paths.
• Service access to fuses, contactors, fans and capacitors is adequate for maintenance without excessive downtime.

Mapping PCS design blocks to IC categories in this way helps align control, sensing, protection and mechanical decisions with vendor roadmaps and long-term maintainability targets.

PCS for ESS – Design FAQs

This FAQ collects the most common ESS PCS design and commissioning questions: when a dedicated bidirectional PCS is needed, how to choose power-stage topology, how to combine gate-driver protection with isolated ΣΔ sensing, how to protect the DC-link and synchronise to the grid, and what to verify before first energisation.