Primary Power Controller

From endrobene wiki :: ITE
Jump to: navigation, search

Primary Power Controller (PPC) - is a power electronics board, designed to control the process of battery charge/discharge, merge separate battery current into one or multiple power rails, control the current flow of output rails and simple filtering. The core of the PPC is a µC which contiguously reads voltage of each battery assembly, incoming charger voltage, control the current of output power rails. At the same time it controls switching of each output rail, enables charging of individual battery, communicates with each of the Battery Charge Controllers, controls air flow and fan speed by taking each section's temperature into account.


Version 2

This version is in production.

The main concept is splitting the charging and control functions into separate boards. The Primary Power Controller's functions are:

1) Connecting external power for charging;
2) Connecting six battery assemblies for charge and use;
3) Allowing manual switching off the separate battery assembly;
4) Communicating with each of the Battery Charge Controllers and receive its charge/discharge level, wear level, temperature, duty time, also monitor the voltage and current level of each battery from an assembly; (I2C interface is used for this purpose)
5) Extend output power rails count to 6 output rails, with separate LC filtering. Up to 4 output rails should have additional external logic TTL output (for service functions).
6) Software switch On/Off of the separate output rail. Monitor each rail power consumption;
7) Communicate with PC board (via UART/COM-port), and report detailed power status information;
8) Control fan speed and internal temperature climate;
9) Wait for the (several) external triggers and run previously programmed functions as a response (such as switching on all the power rails, when external signal is emitted).
10) Reset peripherals

The board have a single µC. Independent charging of battery assemblies is controlled by separate effective switched mode DC-DC converters on each of the Battery Charge Controllers.

Schematic capture

Schematic capture of the Primary Power Controller (rev. 2)


Two-sided PCB of the Primary Power Controller (rev. 2)

Device photo

Device photo of the Primary Power Controller (rev. 2)


Test results


Parts list


Device specific commands


Version 1

Is a current implementation. There are inputs for the 6 Li-Ion battery assemblies (22.2V / 4800 mAh each). Power rail's current of all 6 batteries is merged using multiple power Schottky diodes. There are outputs for sensing battery voltage, through limiting resistor but with no voltage divisor (22.2V, 330 Ohm resistor). A single, up to 27 VDC, input socket power connector (5.5 mm x 2.5mm) is provided to connect external charger (AC/DC power supply), however with no overcharge detection. A transformer based charger (220VAC/27VDC @ 2A) is used to charge batteries. There are 2 output rails with 4 output connectors. Each output rail have its separate LC filter.

See also

External links

Personal tools