The RequestDear Swagatam Majumdar,
The proposed bike generator to 220V converter circuit can be understood with the help of the following description.As requested, the lights are required to be illuminated in sequence in response to the increasing voltage from the generator.
The sequencing feature is implemented by the IC LM3914 which is a dot/bar display driver chip.
The IC responds to a voltage applied across its pin#5 and translates it into a sequencing or incrementing logic high across its 10 output pins.
The outputs may be arranged to produce "dot" mode type of sequencing or "bar" mode type, depending upon the position of the selector switch connected to pin#9 of the IC.
In this design, the generator output is first reduced to 15V DC source through the TIP122 transistor stage and then further dropped to 6V which is then applied to the IC stage for the required functions.
The outputs of the IC are terminated through 10 PNP transistor relay driver stages.
The mode switch should be selected in the "bar" mode for enabling the transistors to latch up in sequence, corresponding to the increase in the voltage level and vice versa, at the input of the IC.
Since the input is restricted to receive a varying voltage from 0 to 5V, a voltage divider stage has been employed in the form of the shown 33k and 4.7k resistor which controls the voltage increment from 0 to 4.8V corresponding to the generator voltage of 0 to 36V approximately.
Understanding the generator 220V Converter Stage
The above stage only handles the sequencing function of the circuit. To light up the AC bulbs we need some means to convert the generator voltage into 220V DC.
This is achieved by using a simple buck-boost network stage, as shown in the following diagram. It's a simple buck-boost converter circuit which is employed for getting the required conversions.
The figure also shows how the output from the buck boost stage needs to be wired across the relay and the bulbs which may be followed for all the relays and the bulbs.
The inductor may be optimized with some trial and error, for example begin trying with 100 turns of 22 SwG over a 10/15mm ferrite rod and measure the voltage by keeping the PWM control toward maximum duty cycle.
Then go on experimenting with the turns and the wire SWG to get the required optimized voltage for illuminating all the 10 bulbs together.
How to Set Up the IC 3914
Using a precision digital multi meter across pin#4 and 6 adjust R1 to get a potential difference of 1.20V.
Next, through a regulated variable power supply apply 4.94V to pin 5, and adjust R4 until the sequence output #10 just illuminates. The adjustments are non-interacting and set.
Dynamo Model- 300-DC
Output Voltage Range-0 to 40 Volts DC
Nominal Current Rating-15 Amps
Peak Current Rating-20 Amps
Peak Power Output: (Charging 12V Battery ) 300 Watts (15V X 20 Amps)
Drive Type-2" Diameter Pulley
Peak Operating Temperature-100 Degrees C
Cooling Method-Air Cooled
Shaft Bearing Type-Ball Bearing
Mounting Bolt Size-6 mm
Wire Lead Length~12"
Wire Lead Size-Size 12 AWG
Approx Weight~8 Lbs
Number of Poles (Brushes)-4
Generator Type-This is a DC permanent magnet motor being used as a generator.
Peak to Peak Voltage-Varies depending on RPMs
Rated Operating Speed-2800 RPMs
Internal Resistance-0.35 Ohms
Typical Amp Hours during 1 hour of use~6 @12V
Typical Amp Hours during 1 hour of use-100 Watt Hours (0.1 KWH)
A related request from one of the dedicated readers:
Dear Sir Swagatam Majumdar,
The requested idea may be implemented with the help of the shown modifications below.
Here each of the outputs of the IC LM3914 have been replaced with an optocoupler in order to drive the subsequent triacs. Only one pinout connection is highlighted in the diagram which needs to be repeated for all the respective pinouts of the IC.
The triacs are connected with the lamps, rated and supplied by 220V mains input.
The shown opto has a bipolar input, meaning its input pins can be connected anyway round across the LM3914 outputs.
The MT2 of the triac is shown connected with the negative of the IC supply, which means the whole circuit is linked directly with mains 220V, and therefore is extremely dangerous to touch in uncovered position, extreme caution from the part of the user is thus expected.