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# System prepended metadata

title: PROJECTS

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## PROJECTS
# Modular Multilevel Power Converter
**Category** - Power Electronics
**Responsibilities** - Firmware and Testing

Widely used to process high amounts of power with low rated power electronic devices, this topology requires precise coordination in order to operate a number of converters to achieve. Similar system architecture is presented below.

![image](https://hackmd.io/_uploads/HJTkD6vD1g.png)


STM32 microcontroller was used to power the entire project leveraging its rich set of APIs and advanced peripherals that were critical to project's success.
* Using High Resolution Timer (**HRTIM**), pulses for Phase Shifted Bridge Conveter (**PSFB**) were generated with necessary dead time insertion.
* **Sine PWM** for Active Front End (**AFE**) was implemented in order to achieve power factor correction by generating reference signals via **d-q** transformation.
* Studied and implemented Phased Locked Loop (**PLL**) algorithms like **SOGI** and **SRFPLL** which form the basis of input for d-q transformation which results in simple PID control.
* **CAN** communication was implemented to transmit operation commands and also for monitoring and protection of connected converters.
* **Calibration** of voltage and current measurements.
* Testing of the above-mentioned system upto **3 KW** by troubleshooting software and hardware issues.
* Maintained a firmware **flow diagram** and a spreadsheet containing information for each and every function in project.
* Maintained a collaborative **git** repository ensuring transparency and communication with customers and stakeholders.
 
# Modbus - 4G gateway (Ongoing)
**Category** - IOT
**Responsibilties** - Hardware, Firmware and Testing

A robust IOT gateway with configurable Modbus as input and the data can be transmitted using MQTT via 4G-LTE to any cloud based server. Furthermore, configuration of device that includes slave addresses and register address can also be via MQTT.

* PCB was designed using Quectel EC200-CN and ESP32 as a host microcontroller.
* Since the above operate at different voltages, a power supply consisting of both switching and ldo voltage regulators was selected.

# Textile Monitoring System
**Category** - IOT
**Responsibilties** - Hardware, Firmware and Testing

Textile machines tend to stop due to variety of reasons which causes significant losses in production which in turn reflects in revenue and profit margins. If the stoppages are reported, swift actions can be undertaken. Also the amount of production can also be calculated via the data processed and transmitted by the PCB.

* After discussions, system parameters were fixed.
* A small form factor PCB was designed powered by **ESP32**.
* Optical isolation was used for input channels.
* **ESP-IDF** APIs were used in developing the firmware of the project.
* Advanced RTOS concepts were used that included task scheduling and queue based data management.
* A web portal for configuration of individual device was also provided in AP mode.
* The data was transmitted using REST API via wifi to a cloud based server.

# PEMF device
**Category** - Medical device
**Responsibilties** - Firmware and Testing

**PEMF** therapy device based on Nordic's NRF52 was developed and tested on a development board.

* Sine wave at a fixed frequency using DAC peripheral was developed which is the main source of magentic therapy.
* GPIO based UI for powering and shutting of device.
* **Zephyr RTOS** was leveraged for time-keeping tasks.


# BLDC Motor controller
**Category** - Power Electronics
**Responsibilties** - Firmware and Testing

An open loop control of BLDC motor was implemeted on STM32 platform. Simple trapazoidal control was used.

* DMA based ADC conversion for speed throtle.
* Rotor position estimation via hall effect sensor.
* PWM waveform generation for H bridge.

# Contact
Feel free to reach out to me at dhruvribbonwala4@gmail.com or +919825155402 for any case of product development.