Views: 255 Author: Ubest Publish Time: 2023-10-30 Origin: Site
A device that converts direct current to alternating current is known as an inverter. Its basic principle is to use the switching characteristics of semiconductor devices (such as field effect tubes or thyristors, for example) to control the power supply voltage and current via rapid switching, resulting in direct current conversion to the corresponding frequency and voltage of alternating current. When the direct current input passes through a semiconductor device in the inverter, it is divided into a series of pulse signals that are filtered and adjusted to produce an alternating current with the same frequency, amplitude, and waveform as the desired output. Inverters are widely used in solar and wind energy generation, household appliances, UPS, and other fields.
The inverter's internal circuit structure is divided into two parts: the control circuit and the power circuit.
The control circuit primarily implements inverter signal regulation and control, including control of the switching state of the thyristor or field effect tube, generation of the high-frequency drive pulse signal, and function protection. A microprocessor or a complex circuit board is typically used in the control circuit.
The power circuit, which includes the rectifier circuit, the filter circuit, and the inverter output circuit, is the core component of the inverter and converts the DC power supply to the AC output. The rectifier circuit converts the input alternating current to direct current, the filter circuit smoothes the rectified direct current, and the inverter output circuit converts direct current to alternating current with the required voltage, frequency, and waveform using semiconductor devices.
The inverter's internal circuit structure is complex, necessitating scientific and precise design and manufacturing processes to ensure its performance and safety.
The full-bridge inverter is a common inverter circuit found in industry, aviation, and the ocean, among other places. The basic idea is to generate AC power by alternating the DC power supply through four switching tubes (typically IGBT or MOSFET).
The four switching tubes in the full-bridge inverter are specifically divided into two groups: the upper and lower bridge arms. The upper bridge arm is made up of two switching tubes and a midpoint, while the lower bridge arm is made up of two switching tubes and a midpoint as well. In each half-cycle, the two switching tubes on one of the bridge arms are turned on and the two switching tubes on the other bridge arm are turned off, resulting in the power supply's DC voltage being successively connected to the outputs L1 and L2 at the midpoint, forming a positive and negative half-cycle of the AC.
It is necessary to perform precise switching control on the four switching tubes in the control of a full-bridge inverter to ensure that they can be switched on and off in different states. To smooth the output waveform and reduce transient and noise interference, auxiliary components such as filter capacitors and inductors are required.
In short, the full bridge inverter has the benefits of simplicity and reliability, stable output, and so on, and is widely used in high-performance applications.
One of the main inverter control technologies is pulse width modulation (PWM). Its basic principle is to control the on-time of the switching tube to adjust the frequency and amplitude of the output waveform.
PWM control, in particular, is used to convert the DC power supply into a series of short pulse signals and control their duty cycle to produce high-quality AC output. The comparative PWM control mode is used in the inverter, which means that the input signal is compared to a Gaussian wave, an error signal is generated, and the control signal of the inverter switch tube is generated based on the error signal, allowing it to realize high-frequency modulation and generate the required waveform. In the concrete implementation, the controller's calculation and the PWM chip's control can complete the opening and closing of each switch tube.
The inverter's PWM control structure consists primarily of the comparator, error amplifier, low-pass filter, and PWM controller. The comparator is primarily in charge of producing the error signal and feeding it into the error amplifier. The PWM control signal is output by the error amplifier after it has been amplified. To control the output waveform, the PWM controller sends the PWM signal to the switching tube, such as an IGBT or MOSFET.
In short, PWM control is an important technology for inverters that allows them to produce high-quality AC output with high precision, stability, and other characteristics. It has found widespread application in solar power generation, electric vehicles, and other fields. Related product: 51.2V 200AH Wall-mounted Home Energy Storage System.
The following are the main inverter communication protocols:
Modbus is a serial communication protocol that allows data to be exchanged between devices. The Modbus protocol in the inverter allows for remote monitoring and control, including real-time monitoring of inverter output power, voltage, current, and other parameters, as well as adjusting the output waveform and frequency.
The CAN bus protocol is a network protocol that is based on a wide area network (WAN) and has high reliability, speed, and system integration characteristics. The CAN bus protocol in the inverter allows for data exchange and control between multiple inverters, as well as communication with other devices.
Ethernet is a standard network protocol that is based on local area networks (LANs). Its data transmission rate is fast, it is highly flexible, it supports a wide range of applications, and it has other characteristics that allow the inverter to communicate via the Internet, such as the use of a Web-based interface to set inverter parameters and perform other functions.
Zigbee is a low-power wireless protocol that can create a stable and secure network in the home, office, and other settings, allowing for direct communication between target devices. Adoption of the Zigbee wireless protocol in the inverter can enable wireless communication between the inverter and other devices, thereby expanding the scope of monitoring and control.
In short, different communication protocols are used in the inverter to achieve data exchange and remote control more quickly and accurately, providing users with more efficient and convenient services.
In the BMS (battery management system), the home energy storage inverter primarily performs the following functions:
The home energy storage system's battery stores direct current, but alternating current is required when the home uses electricity. Inverters can convert direct current to alternating current and deliver it to household appliances or the public grid.
Energy storage inverters can not only provide power to the home, but they can also feed excess electrical energy (from photovoltaic modules, for example) into the grid. At the same time, the inverter can adjust the household electricity load, reduce peak power consumption, and achieve valley height balance.
To achieve accurate control and protection of the energy storage system, the inverter can be integrated with the battery management system (BMS) by monitoring and controlling the battery voltage, current, and other parameters. When the battery is low, for example, the inverter can stop supplying power to the grid per the BMS's instructions to avoid damaging the battery and reducing its service life.
The inverter can optimize the control of household electricity loads while reducing reliance on traditional fossil energy to achieve energy savings, emission reduction, and environmental protection. At the same time, the inverter can buy and sell electricity in the power market at the optimal time, lowering electricity costs.
In short, the home energy storage inverter, as one of the core products of the home energy management system, has a variety of important functions and roles and can further improve the efficiency and control accuracy of home energy use by integrating with the battery management system and other devices.
The inverter's DC-DC refers to the DC-DC converter. DC-DC is primarily used in inverters to adjust and convert the input voltage to meet the power supply requirements of the inverter and its output load. DC-DC can specifically perform the following functions:
When the inverter's input voltage is lower than the output voltage, DC-DC can increase the voltage to ensure the inverter's normal operation. When the input voltage is greater than the output voltage, the DC-DC can reduce the voltage to reduce the inverter's power loss.
By changing the switching frequency, duty ratio, and other parameters, DC-DC can achieve accurate control of the output current based on the needs of the output load, preventing the impact of circuit overload or power supply fluctuations on the output load.
DC-DC can also achieve energy storage and management, such as the storage and reuse of renewable energy generated by photovoltaic or wind energy, through the use of battery packs.
In the event of an inverter overload, short circuit, Undervoltage, or other abnormal conditions, DC-DC can immediately cut off the input power to prevent further damage to the inverter and output load.
