Skip to main content

"Mastering Power Conversion: Designing an Inverter Circuit with Feedback Control"

Mastering Power Conversion: Designing an Inverter Circuit with Feedback Control

In this article, we will look at two inverter circuits that use automatic feedback control to ensure that the output does not exceed the normal stated AC output level or the specified overload circumstances.

What is Inverter Feedback Control?

Inverters typically include a feedback loop to regulate the output voltage and current and keep them from exceeding unsafe limits.

In this system, the output AC mains voltage is first reduced to a correspondingly lower level before being sent to the control IC's shut down pin. The stepped-down feedback voltage now follows the output AC and changes up and down proportionally.

The control ICs shut down circuitry compares and monitors this feedback signal with a fixed fer obtained from the inverter's battery voltage.

If the output voltage tends to climb over the predetermined value and beyond the reference level, the error amplifier is activated, which shuts down the inverter output PWM. When this occurs, the output voltage immediately drops, causing the feedback signal to fall below the reference value. This condition causes the IC's shut down feature to be disabled, and the IC to resume normal operation.

If the output tries to increase above the unsafe level again, the above procedure is repeated in the same manner, and this continues indefinitely and rapidly, guaranteeing that the output voltage is never permitted to exceed the stated unsafe threshold.

Inverters SG2524/SG3524/SG3525 Feedback Control

The first example circuit explains how to add an automatic feedback control to an SG2524 inverter circuit. The same idea may be applied to any other inverter versions that use the ICs SG3524 and SG3525.



The feedback control loop is configured as follows, which can be understood as follows:

A 4 diode bridge rectifier circuit is used to first rectify the 220V AC output.

The rectified high voltage DC is reduced to a lower DC level, typically 5V to 10V, via a voltage divider network constructed of 220K resistors and a 10K preset.

The 10K preset is used to fine-tune the feedback voltage until the output voltage is precisely controlled.


The feedback is obtained from the centre arm of the 10K preset and supplied to the error amplifier's non-inverting input pin #1 of the IC 2524.

This error amplifier is nothing more than an internal opamp set for managing the PWM of output pins 11 and 14.

The inverting or (+) input pin#2 of the op amp is held at a fixed reference level of +2.5V by a pair of voltage divider resistors placed around the IC's pin#2 and pin#16. The +5V reference potential is obtained from IC pin #16 and then reduced to 2.5V via the two voltage divider resisters.

Because pin#2 of the error amplifier is fixed at 2.5V reference, if the pin#1 of the opamp climbs over the 2.5V level, the IC's PWM feature is activated, causing the output PWM to the transistors to narrow.
The feedback 10k setting is set so that when the output voltage reaches the stated unsafe high voltage level, the feedback voltage at pin#1 becomes 2.6 V.

When the pin#1 receives a 2.6 V, the internal error amp activates, restricting the output PWMs to the transistors, causing the output voltage to drop to the safe lower values.

Feedback in an IC 555 Inverter

You may have previously read the piece that describes how to make basic 555-based inverters.

Although all of these inverters are well-designed and will produce the necessary 220 V or 120 V from a simple IC 555 configuration, they lack a built-in feedback system to ensure a steady output voltage.

The diagram below shows how a regular IC 555 inverter may be changed into an improved inverter using a simple feedback loop control network.

In this circuit as well, the 220V output from the transformer is rectified to a DC level before being stepped down via a resistive network consisting of a 220K resistor and a 10k capacitor.

The 10k preset centre lead is configured with the NPN transistor BC547, the collector of which can be seen attached to the IC's pin #5, which is the control input.
We know that when pin#5 is open, the PWM at the IC's output pin#3 is at its maximum; however, as the potential at pin#5 is reduced, the output PWM decreases proportionally.

When pin#5 is grounded, the output PWM at pin#3 becomes exceedingly narrow, with essentially no average voltage at this pinout.

When the output voltage of the IC 555 feedback circuit tends to grow over the unsafe high voltage threshold, as established by the 10k preset, the base of the BC547 gradually begins to bias. When this happens, the BC547 begins to conduct, causing the IC's pin #5 to gradually ground. The grounding of the IC's pin #5 causes the output PWM at pin #3 to narrow, causing the output voltage to return to normal values.

Labels:

Comments

Post a Comment

Popular posts from this blog

Miniature 8-cylinder engine in operation

  Working miniature 8-cylinder engine The Intriguing World of Miniature 8-Cylinder Engine Operation The intricacy and strength of conventional V8 engines are combined into compact, useful models in miniature 8-cylinder engines, which are a true engineering marvel. Both engineers and enthusiasts are drawn to these tiny engines because they are the epitome of mechanical creativity and fine craftsmanship. The design, applications, and reasons why working miniature 8-cylinder engines have grown in popularity among model builders and collectors will all be covered in this article. What is an 8-cylinder miniature engine? An actual V8 engine is shrunk down to create a small 8-cylinder engine. Usually built to run on a variety of fuels, including compressed air or gasoline, these engines may simulate the firing patterns, exhaust noises, and moving parts of full-size V8 engines. They are frequently constructed as functional models, which means that the engine functions and runs much like...
1 comment
Read more

Getting Started: The Prospects for Automotive Innovation

Getting Started: The Prospects for Automotive Innovation Revving Up: The Future of Automotive Innovation  Demands for sustainability, changing consumer expectations, and technology breakthroughs are all contributing to the automotive industry's dramatic transition. A number of significant themes are influencing the direction of automotive innovation as we prepare for the future. 1. Electric Vehicles (EVs) on the Rise At the vanguard of automotive innovation are electric automobiles. The transition to electric vehicles (EVs) is speeding up as a result of governments' demands for greener alternatives and consumers' growing environmental consciousness. To improve range and shorten charging times, major automakers are making significant investments in electric technology, diversifying their product lines, and creating more effective batteries. It is anticipated that advancements in solid-state batteries and charging infrastructure would increase EVs' viability and make them...
2 comments
Read more

What is the smallest 8 cylinder engine?

 When people talk about engines, the V8 configuration frequently conjures images of powerful trucks, high-performance sports cars, and roaring muscle cars. Large displacement and tremendous power aren't typically associated with V8 engines, though. Over the years, manufacturers and engineers have developed incredibly compact V8 engines for a range of specific applications. These engines demonstrate the accuracy and inventiveness of contemporary engineering. Let's explore the intriguing realm of the tiniest V8 engines ever made   What Defines a "Small" V8 Engine? Displacement, power output, and intended use must all be taken into account in addition to physical dimensions when defining a "small" V8 engine. The entire amount of gasoline and air that the engine's cylinders can hold is known as displacement, and it is commonly expressed in liters or cubic centimeters (cc). Compared to the standard 4.0 to 6.0-liter V8s seen in normal cars, a small V8 engine t...
Post a Comment
Read more

How to Make a Steam Engine Working Model

  How to Make a Steam Engine Working Model A great practical project that blends science, engineering, and creativity is building a working model of a steam engine. This tutorial will show you how to build a simple steam engine that illustrates the fundamentals of steam power using easily accessible materials. Materials Needed Small tin can or metal container (for the boiler) Copper tubing (approximately 1/4-inch diameter) Small piston or syringe (to act as the engine's cylinder) Wooden or metal base (for mounting components) Alcohol burner or tea light candle (as a heat source) Small flywheel (can be made from a toy car wheel or similar object) Rubber tubing (optional, for connecting components) Epoxy glue or soldering kit Drill and bits Safety goggles and gloves Easy-to-follow directions 1. Understand the Principles Learn how a steam engine operates before you start construction. When water is heated, steam is created, which expands and powers a piston in a steam engine. B...
Post a Comment
Read more

Illuminate Your World: Exploring the Bright Potential of Solar Lights

ENLIGHTEN YOUR REALITY: INVESTIGATING THE SPLENDID CAPABILITY OF SUN BASED LIGHTS Illuminate Your World: Exploring the Bright Potential of Solar Lights   Imagine illuminating your outdoor space with bright, reliable light, all while saving money and reducing your environmental impact. Solar motion sensor lights are making this dream a reality, seamlessly blending convenience and sustainability. Let’s explore why these innovative solutions are changing the face of outdoor lighting Shining a Light on Efficiency: Solar motion sensor lights are champions of efficiency. Equipped with powerful LED bulbs (like the 66 or 180 in our models!), they emit a long-lasting glow, powered by the sun’s energy. Their premium solar panels convert sunlight into electricity, storing it in rechargeable batteries for night-time use. This automatic system ensures efficient energy usage, providing reliable lighting from dusk till dawn. Bright Ideas, Long Lifespan: Durability and longevity are key features o...
1 comment
Read more