Universal Power Supply/Bill of Materials

Basics

• This page explores what is needed to make the Universal Power Supply

Funtions

The Universal Power Supply should provide these functions:

• Inverter
• Solid state transformer - 1200V, short range transmission lines - $60 cost of 45 kW transformer. [1]
• Induction furnace
• Plasma cutter
• Welder
• Laser cutter
• Charge controller to batteries
• Power conditioning from a windmill
• Induction heater
• Contactor
• Electric motor speed contoller
• Stepper motor controller

Part Reduction

What is the minimum number of electronic parts required to build the Universal Power Supply?

• Arduino for control. Arduino can also measure frequency to 50kHz for feedback - [2]
• IGBTs - choose one that can be scaled extensively, 10kW range (20A x5, 100V)
• Resistors
• Capacitors (filters)
• Small transformers
• Current sensors - Hall Effect Sensors
• Terminal blocks, 50A [3]
• Wire (8 ga, 55A, 600V) [4]
• Switches. Small switches, with IGBT serving as larger switch or contactor
• 200A contactor relay - 48DC - [5]
• Go for 600V on components, at 50A for wires, need 7 wires for 210kW - manageable as a modular system

Pulse Width Modulation

BOM for high frequency up to 65kHz is done with Arduino.

• Arduino has 500hz pulse width modulation - [6]. And 1000hz modulation - [7]. Up to 62.5 kHz - [8]
• PWM.h library for arduino lets you select frequency - [9]
• PWM library for Arduino - 65kHz, or up to 2Mhz - but is i/o fast enough at above 65kHz? -[10]
• More about Arduino PWM, but this doesn't go above 1kHz in examples - [https://www.arduino.cc/en/Tutorial/SecretsOfArduinoPWM
• Or you can obtain PWM at the software level - [11]

Inverter

Needs Arduino, 4 gate drivers, and 4 transistors as a minimum set.

• Modified Sinusoidal pulse width modulation - http://www.theorycircuit.com/arduino-inverter-circuit/

• Sample inverter using a transformer

• Transformerless - [12]

Voltage Amplification

• Boost converter - practical gain limit of 6 - [13]
• Cascade of half-wave doublers (Cockcroft-Walton multiplier) appears scalable - [14]

Inverter Welder

• 10 kHz, about 15-30V [15]

Plasma Cutter

• 400VDC for cutting. 5000VAC for spark. [16]

Laser

• CO2
• Solid State

Induction Heating Frequency and Voltage

• Tiny 30W induction heater with part list, air solder - [17]
• $1-2k for 10kW induction furnace. Arduino controlled - but missing open source software - [18]
• Typical - 10kHz to 1 Mhz frequency - [19]
• Resonant LC circuit - [20]
• Excellent overview of a basic system - [21]. Diagram of this - [22]
• Royer Oscillator, Wikipedia - [23]
• Melting calculator- Temperature rise calculator. Steel melts at 1400C. [24]
• ZVS induction on Hackaday - [25]
• ZVS Induction heater - 1 kW - $40 - [26]. Is this scalable simply by larger components?
• IGBT for ZVS - 20kW capacity - $4 - [27]
• Furnace, tuning by a pot, tuned condition by diode light - [28]. Youtube Channel - ex, detailed explanation of a 12V power supply - [29]
• Paper. Their resonant loop locking method is too complicated - [30]
• 2015 paper on fuzzy logic for maximum power output of induction furnace - [31]
• Patent on frequency control - [32]
• Algorithm is in principle simple: measure phase between I and V of load. If phase is greater than 0, decrease the frequency; if phase is less than 0, increase the frequency. Is Arduino or Raspberry Pi fast enough to do this at about 100kHz? - [33]. Pi Zero is 700 Mhz - 100 kHz should be achievable readily.
• Zero point crossing and phase control - [[34]]

OCI Pages

• Page with design request on the Open Circuit Institute Page (Here)
• Finished design published on the Open Cicuit Institute Page (Here)

See Also

• Universal Power Supply