PowerPoint ® Presentation Chapter 8 Inverters AC Power Inverters Power Conditioning Units Inverter Features and Specifications

PowerPoint® PresentationPowerPoint® Presentation

Chapter 8Chapter 8InvertersInverters

AC Power • Inverters • Power Conditioning Units • Inverter Features and Specifications

AC Power • Inverters • Power Conditioning Units • Inverter Features and Specifications

Chapter 8 — InvertersChapter 8 — Inverters

If voltage and current signals are either always positive or always negative, they are DC waveforms. If the signals switch between positive and negative, they are AC waveforms.

If voltage and current signals are either always positive or always negative, they are DC waveforms. If the signals switch between positive and negative, they are AC waveforms.


AC waveforms can take a variety of shapes.AC waveforms can take a variety of shapes.


Certain parameters are integral to defining the characteristics of an AC waveform.

Certain parameters are integral to defining the characteristics of an AC waveform.


Three-phase power is composed of three separate voltage waveforms that are 120° out of phase.

Three-phase power is composed of three separate voltage waveforms that are 120° out of phase.


Voltage variations outside allowable ranges include voltage sags, voltage swells, and transients.

Voltage variations outside allowable ranges include voltage sags, voltage swells, and transients.


Three-phase voltage and current waveforms are unbalanced if they are not equal in magnitude.

Three-phase voltage and current waveforms are unbalanced if they are not equal in magnitude.


Harmonics can add to the fundamental frequency to produce distorted waveforms.

Harmonics can add to the fundamental frequency to produce distorted waveforms.


Resistive loads keep the voltage and current waveforms in phase, while reactive loads cause the current waveform to lead or lag the voltage waveform.

Resistive loads keep the voltage and current waveforms in phase, while reactive loads cause the current waveform to lead or lag the voltage waveform.


Inverters are available in many different configurations and ratings.

Inverters are available in many different configurations and ratings.


Stand-alone inverters are connected to the battery bank and supply AC power to a distribution panel that is independent of the utility grid.

Stand-alone inverters are connected to the battery bank and supply AC power to a distribution panel that is independent of the utility grid.


Utility-interactive inverters are connected to the PV array and supply AC power that is synchronized with the utility grid.

Utility-interactive inverters are connected to the PV array and supply AC power that is synchronized with the utility grid.


String inverters are commonly used in residential and small commercial PV systems.

String inverters are commonly used in residential and small commercial PV systems.


Large commercial systems often use central inverters, which have higher power ratings and are suited for arrays with identical modules that are aligned alike.

Large commercial systems often use central inverters, which have higher power ratings and are suited for arrays with identical modules that are aligned alike.


Utility-scale inverters are very large systems that output AC power to the grid at voltages up to 35 kV.

Utility-scale inverters are very large systems that output AC power to the grid at voltages up to 35 kV.


Microinverters are small utility-interactive inverters that are supplied by a single PV module.

Microinverters are small utility-interactive inverters that are supplied by a single PV module.


Solid-state switching devices used in PV inverters include transistors and thyristors.

Solid-state switching devices used in PV inverters include transistors and thyristors.


Line-commutated inverters use an external AC signal to activate and deactivate the inverter switching devices.

Line-commutated inverters use an external AC signal to activate and deactivate the inverter switching devices.


H-bridge inverter circuits use two pairs of switching devices to direct a DC input to the output in both directions.

H-bridge inverter circuits use two pairs of switching devices to direct a DC input to the output in both directions.


Push-pull inverter circuits use one pair of switching devices and a transformer to alternate the direction of direct current.

Push-pull inverter circuits use one pair of switching devices and a transformer to alternate the direction of direct current.


Square waves can be modified by adjusting the duration and magnitude of the pulses.

Square waves can be modified by adjusting the duration and magnitude of the pulses.


Combining multiple modified square waves with different magnitudes and durations results in a multistepped modified square wave that more closely approximates a sine wave.

Combining multiple modified square waves with different magnitudes and durations results in a multistepped modified square wave that more closely approximates a sine wave.


Pulse-width modulation (PWM) at high frequencies generates the truest approximation of a sine wave.Pulse-width modulation (PWM) at high frequencies generates the truest approximation of a sine wave.


Power conditioning units are inverters that also perform other power control and conversion functions.

Power conditioning units are inverters that also perform other power control and conversion functions.


Transformers use induced magnetic fields to transfer AC power from one circuit to another while transforming the power to higher or lower voltages or providing electrical isolation.

Transformers use induced magnetic fields to transfer AC power from one circuit to another while transforming the power to higher or lower voltages or providing electrical isolation.


The primary and secondary windings in an autotransformer share some of the same windings.

The primary and secondary windings in an autotransformer share some of the same windings.


Inverter nameplates include much of the needed information for sizing and operating the inverter.

Inverter nameplates include much of the needed information for sizing and operating the inverter.


At high temperatures, an interactive inverter may limit current input by raising the input voltage, which also lowers power input and output.

At high temperatures, an interactive inverter may limit current input by raising the input voltage, which also lowers power input and output.


Most inverters operate from a relatively wide range of input voltages, but the range for MPPT operation is usually smaller.

Most inverters operate from a relatively wide range of input voltages, but the range for MPPT operation is usually smaller.


In order to output AC voltage within the specified range, the DC input voltage must meet certain minimum values.

In order to output AC voltage within the specified range, the DC input voltage must meet certain minimum values.


Inverters may limit maximum DC input current with increasing DC input voltage.

Inverters may limit maximum DC input current with increasing DC input voltage.


Most sine wave inverters maintain high efficiency over a wide operating-power range.

Most sine wave inverters maintain high efficiency over a wide operating-power range.


Inverter enclosures may include protective devices such as circuit breakers.

Inverter enclosures may include protective devices such as circuit breakers.


Inverter interfaces include on-board screens, remote data monitors, and computerized data acquisition and processing software.

Inverter interfaces include on-board screens, remote data monitors, and computerized data acquisition and processing software.

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PowerPoint ® Presentation Chapter 8 Inverters AC Power Inverters Power Conditioning Units Inverter Features and Specifications