glenn schrooyenandClaude Opus 5
e46175559b
S-1. The frozen branch admitted a correction only if it shrank |i_w|. That is unsatisfiable for BOTH signs of error whenever |correction| > 2*|i_w|, i.e. whenever the integrator is near zero, so the loop stopped moving and the freeze could never clear - it clears when the inverter tracks, and not tracking is what saturation means. Measured: 0 W held into a 2 kW import indefinitely, where release/1.0 recovers on the next cycle. Re-encoded as the same asymmetric rule the output freeze has always used: may not wind further in the direction it is already pushing, may fall, cross zero or reverse. Same interpretation, an encoding that cannot deadlock. S-2. integrator_max_w defaulted to 1.5x max_w, which ADDED windup: in release/1.0 the accumulator was the post-clamp command and could never pass the rail. Default is now "follow max_w" (config 0 = unset). Measured on the 4000 W load-drop sim, first cycle after the drop: 1000 W at the new default, 1800 W at 3000. DOCS row inverted - the useful direction is below max_w, and the 14 768 W anecdote is a vendor controller, not evidence about this code. S-3. The claim that i_w=None preserved release/1.0 exactly was false, because the S-1 gate ran regardless of seeding. It is true again, and now asserted rather than asserted-about: 3024-case exhaustive comparison against a transcription of the old law, over both freeze states, both signs and either side of the deadband. Added the carried-i_w convergence/overshoot sim that the shipped configuration was missing. S-4. Cycles are distinct meter values, not seconds: cycle() runs only when the meter reading changes, so the window has no wall-clock bound. Comment and DOCS corrected; the stall is detection latency, not a windup hazard, because the same condition stalls the whole loop. test_control.py: 33 -> 41 checks, all passing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
138 lines
6.2 KiB
Markdown
138 lines
6.2 KiB
Markdown
# GoodWe RS485 Controller
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Drives a GoodWe ES/BP battery inverter over its RS485 meter bus: holds net grid
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exchange at zero, and runs a monthly battery maintenance cycle so the BMS can
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balance cells and recalibrate its coulomb counter.
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Installers: read `FIELD-GUIDE.md` in the repository. It is not optional reading —
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it contains the commissioning gates and the failure modes.
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## Before you start
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You need:
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- A GoodWe **ES / BP family** inverter (AA55 / RS485 meter-bus generation)
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- The vendor's meter-emulating controller **disconnected** from the bus
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- A T-CAN485 (ESP32) flashed with `firmware/goodwe-master.yaml`
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- A grid-power sensor already working in Home Assistant, updating every ~5–10 s
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## The safety model, in short
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The inverter **holds its last command forever** — it has no meter-timeout. So:
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- The ESP32 commands 0 W if this add-on stops refreshing for ~30 s, and keeps
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commanding it.
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- This add-on commands 0 W when its inputs go missing, when you stop control,
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and when it shuts down.
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- The **optional RS485 e-stop** is the only thing that covers this machine
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dying. Without it, a failed host leaves the battery latched at its last
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command until someone intervenes.
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**If anything looks wrong: stop the add-on.** That commands 0 W and the
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hardware holds it there.
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## Configuration
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### Sources
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| option | required | meaning |
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|---|---|---|
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| `meter_entity` | yes | Net grid power. **Positive must mean importing** |
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| `meter_invert` | | Flip the sign if the meter reports the other way |
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| `soc_entity` | yes | Battery state of charge — use the **ESP32's own read** |
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| `batt_entity` | yes | Battery power — again the ESP32's read, `+` = discharging |
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| `batt_invert` | | Flip if needed |
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| `setpoint_entity` | yes | The ESPHome `number.*_goodwe_setpoint_w` |
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Use the ESP32's readings rather than the inverter's cloud or dongle sensors:
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those serve cached values, and a stale reading here ends the maintenance charge
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phase having charged nothing.
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### Control
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| option | default | meaning |
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| `max_w` | 2000 | Hard limit on what may be commanded. Start low, raise after commissioning |
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| `gain` | 0.6 | Correction per cycle. **At the limit — do not raise** |
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| `slew_w` | 1000 | Maximum change per cycle |
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| `deadband_w` | 15 | Ignore errors smaller than this |
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| `target_grid_w` | -10 | What the meter should rest at. Negative = a slight export |
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| `step_w` | 10 | Quantisation |
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| `saturation_w` | 500 | Divergence that counts as "the inverter is at a limit" |
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| `saturation_cycles` | 3 | How many consecutive cycles before freezing. **Do not set to 1** |
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| `integrator_max_w` | 0 | Bound on the loop's accumulator, and 0 means "same as `max_w`". Caps how much stale error can be waiting to unwind when the sign flips. **Do not raise it above `max_w`** - the output clamp already bounds what is commanded, so the only thing extra headroom buys is more cycles of wrong-direction power after every saturation event. Lowering it below `max_w` is the useful direction |
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| `heartbeat_s` | 10 | Refresh interval; must stay well under the firmware watchdog |
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| `stale_input_s` | 15 | How long inputs may be missing before commanding 0 W |
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| `auto_start` | false | Start controlling on boot (only after commissioning) |
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#### Why `target_grid_w` is not zero
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The deadband is a one-way ratchet: any resting point inside it holds until
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something disturbs it. Import and export are **separate registers on the
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meter**, so a rest point of +14 W is billed for every second it holds and no
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amount of export cancels it - 14 W all day is 0.34 kWh.
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Biasing the target below zero moves that residue into the export register,
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which is not billed. The resting band becomes `target ± deadband`, so:
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| `target_grid_w` | resting band | worst billed leak | export given away |
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|---|---|---|---|
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| 0 | -15 … +15 W | ~15 W (0.35 kWh/day) | none |
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| **-10** | -25 … +5 W | ~5 W (0.12 kWh/day) | ~10 W |
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| -15 | -30 … 0 W | none | ~15 W (0.36 kWh/day) |
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Set it to `-deadband_w` if injection is worth nothing to you and you would
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rather give the energy away than buy it back. Set it to `0` if you are paid
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properly for export, or if you are debugging and want the loop centred.
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⚠️ This is a **billing** knob, not a speed knob. If import is arriving in
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bursts rather than as a trickle, the cause is tracking lag, and this will not
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help - see "Why the tuning is what it is".
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### Maintenance
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| option | default | meaning |
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| `maintenance_enabled` | false | Enable the monthly cycle |
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| `maintenance_interval_days` | 28 | Minimum gap between cycles |
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| `maintenance_start_hour` | 10 | Hour of day a due cycle begins |
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| `maintenance_discharge_w` | 2500 | Drain rate (exports the surplus) |
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| `maintenance_charge_w` | 2500 | Charge ceiling, capped again by peak headroom |
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| `maintenance_soc_floor` | 11 | Drain target — stay just above the inverter's own floor |
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| `maintenance_soc_target` | 99 | Charge target |
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| `maintenance_hold_min` | 120 | Hold at full so the BMS can balance |
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### Tariff (all optional)
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| option | meaning |
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| `peak_forecast_entity` | Quarter-hour demand forecast, for capacity-tariff markets. Empty = no cap |
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| `peak_cap_w` | The site's capacity-tariff target |
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| `price_now_entity`, `price_avg_entity` | Dynamic tariff. Empty = never force a paid grid top-up |
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On a capacity-tariff site the maintenance charge is capped by the headroom left
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under `peak_cap_w`, and if the forecast goes over the cap the charge-only clamp
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is dropped so the battery can shave the peak instead. Money outranks the
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maintenance schedule.
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### Site
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| option | meaning |
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| `estop_fitted` | Whether the RS485 e-stop is installed. Drives the warning banner |
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| `log_level` | `trace`/`debug`/`info`/`warning`/`error` |
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## The Web UI
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The ingress panel shows live values, why the controller is commanding what it
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is, and a **Commissioning** checklist that names any problem in words. It also
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carries the three buttons: start/stop control, force a maintenance cycle, and
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abort one.
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## Status entities
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If an MQTT broker is available the add-on publishes setpoint, grid power,
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battery power, state of charge, maintenance phase and controller status by MQTT
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discovery. This is observability only — the controller works fine without a
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broker, and MQTT problems can never affect control.
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