Add support for SG600MD Solar Inverter

Issue #369

ACKNOWLEDGEMENTS.md

@@ -168,3 +168,4 @@ Further device support has been made with the assistance of users.  Please consi
 - [austinhodak](https://github.com/austinhodak) for contributing support for generic dimmable lights.
 - [x5500](https://github.com/x5500) for contributing support for Loonas curtains.
 - [mypixies](https://github.com/mypixies) for assisting with support for Moes dimmer switch.
+- [BeardedTinker](https://github.com/BeardedTinker) for assisting with support for SG600MD smart inverter.

DEVICES.md

@@ -161,6 +161,7 @@
 - Compteur digital electric (single phase)
 - PC321-TY 3 phase power clamp meter
 - PJ-1103 power clamp meter
+- SG600MD Smart Solar Inverter (also SG700MD, other SGxx0MD and SGxx0W models) sold under various brands
 - SmartMCB SMT006 energy meter
 
 ### Battery Charger

custom_components/tuya_local/devices/solar_inverter.yaml

@@ -0,0 +1,91 @@
+name: Smart Inverter
+products:
+  - id: xcgsq9ggffz7lqhh
+    name: SG700MD
+primary_entity:
+  entity: sensor
+  name: Energy
+  class: energy
+  dps:
+    - id: 2
+      type: integer
+      name: sensor
+      unit: kWh
+      class: measurement
+      mapping:
+        - scale: 100
+    - id: 15
+      name: model
+      type: string
+    - id: 16
+      name: inverter_id
+      type: string
+secondary_entities:
+  - entity: sensor
+    name: Power
+    class: power
+    category: diagnostic
+    dps:
+      - id: 10
+        type: integer
+        name: sensor
+        unit: W
+        class: measurement
+        mapping:
+          - scale: 10
+  - entity: sensor
+    name: DC current
+    class: current
+    category: diagnostic
+    dps:
+      - id: 102
+        type: integer
+        name: sensor
+        unit: A
+        class: measurement
+        mapping:
+          - scale: 100
+  - entity: sensor
+    name: DC voltage
+    class: voltage
+    category: diagnostic
+    dps:
+      - id: 103
+        type: integer
+        name: sensor
+        unit: V
+        class: measurement
+        mapping:
+          - scale: 10
+  - entity: sensor
+    name: AC voltage
+    class: voltage
+    category: diagnostic
+    dps:
+      - id: 104
+        type: integer
+        name: sensor
+        unit: V
+        class: measurement
+        mapping:
+          - scale: 10
+  - entity: sensor
+    name: AC current
+    class: current
+    category: diagnostic
+    dps:
+      - id: 105
+        type: integer
+        name: sensor
+        unit: A
+        class: measurement
+        mapping:
+          - scale: 100
+  - entity: switch
+    name: Inverter switch
+    category: config
+    dps:
+      - id: 101
+        type: boolean
+        name: switch
+        optional: true