Blog Posts of '2021 February'

An inverter is a device composed of inverter device and component, which is directly different from a transformer. In other words, the inverter can realize DC input and then output AC. The working principle is similar to that of a switching power supply, but the oscillation frequency is within a certain range. For example, if the frequency is 50Hz, the output will be AC 50Hz. An inverter is a device that its frequency can be changed. UPS (Uninterruptible Power System/Uninterruptible Power Supply) is system equipment that connects batteries (mostly lead-acid maintenance-free batteries) with the host, and converts DC power into mains power through module circuits such as the host inverter. It provides uninterrupted power, and is mainly used to some equipment that requires high power supply stability.

Centrifugal pump is a pump that relies on the centrifugal force generated when the impeller rotates to transport liquid. What causes the centrifugal pump to fail to deliver water? Here are the failure analyses. 1. Some users do not fill enough water before the pump is started. Sometimes it seems that the water filled has overflowed from the vent hole, but the pump shaft is not rotated and the air is completely discharged, causing a little air to remain in the inlet pipe or pump body.

The solar inverter is the safety control center of PV system. Thus, during the PV system operation, the inverter condition, including the temperature and operation of interval cavity and main element, the bus voltage and the communication among chips, shall be inspected from time to time. In addition, the insulation among components and DC system, the DC voltage and current, the AC output voltage, current and frequency shall also be inspected. In case of any failure, it shall be solved in time.

The difference of series inverter and parallel inverter is that they use different oscillation circuits. The series inverter connects L, R and c in series and parallel inverter connects L, R and c in parallel. Series Inverter vs. Parallel Inverter The load circuit of series inverter has low impedance. The voltage source power supply is required and the large filter capacitor shall be connected at the DC power terminal in parallel. If the inverter fails, it is difficult to provide protection because of large surge current. The load circuit of parallel inverter shows high impedance and the current source power supply is required. The large reactor shall be connected at the DC power terminal in series. If the inverter fails, it is easy to provide protection because the large inductor can limit the current so as to avoid large impact.

Solar inverter is an electronic product and its service life is limited due to the limit of the components. However, many inverters are damaged before the service life expires and the actual service life is shorter than the designed theoretical service life. The service life is determined by the product quality and the post-period installation, operation and maintenance conditions. So, how to improve the service life of the solar inverter?

Solar inverter shall realize the highest efficiency in wide power range conditions. Meanwhile, using a solar inverter shall meet the strict safety requirements. The property of the solar inverter is essentially determined by the accurate measurement of basic electricity. The safety criteria that shall be followed by solar inverter designers may become stricter and stricter. For instance, just like the limit on the input of DC power into the grid, some consensus may be reached on the allowable total harmonic wave of the solar inverter output current. By far, many different local limitations are put forward based on the layout situation. Thus, it requires that when the power grid frequency is greatly higher than 50Hz or 60Hz, the current shall be measured accurately.

In the solar PV grid system, the solar module, inverter and power grid can constitute the electrical system. The component will convert the solar energy based on the solar radiation and then inverter will output related power. Thus, an on grid inverter does not have special demand on the AC overload because basically the inverter output power will not exceed component power. In the solar PV off-grid system, component, battery, inverter and load constitute the electrical system. The output power of the inverter is decided by the load. The start power of motor of some inductive-load devices like air conditioner or water pump is 3-5 times of the rated power. Thus, the off grid inverter has special requirements on the overload situation. In solar PV off grid system, the output power is determined by the load. When motor or other devices with inductive load are started, the large current will be required within short time. The PV system and battery are not able to provide this energy. In addition, if the lithium battery outputs excessively in short time, it may explore. However, the capacitor, inductor, transformer of the off grid inverter can store power and will not be damaged even if it amplifies the output for several times in a short time. Therefore, off grid inverters can be overloaded several times.

Solar pump inverter is used to control and regulate the operation of solar water pump system (PV pumping system). It can convert the DC from the solar array into AC to drive the water pump. In addition, it can adjust the output frequency in real time according to the sunlight intensity so as to achieve maximum power point tracking (MPPT). Solar pump inverter is one of the various types of power inverters. Its function is similar with the function of common on grid inverter. The two inverters are both used to convert solar DC into AC. But the solar pump inverter is greatly improved. Thus, it can greatly save the system cost and can expand the solar energy application range.

Full name of the micro inverter is micro solar on grid inverter. It generally refers to inverters with power below 1500W and module-level MPPT. It is mostly used in photovoltaic power generation systems. Micro is relatively small compared to traditional centralized inverters. The micro inverter inverts each component. Its advantage is that each component can be independently controlled by MPPT, which can greatly improve the overall efficiency. At the same time, micro inverter can also avoid the DC high voltage, poor light effect, and wooden barrel effect of the centralized inverter. Micro inverters manage the collection of solar energy at the level of a single panel to improve the efficiency of the solar equipment, rather than working in the entire system like a central inverter. In the past, in order to ensure maximum power output during solar energy harvesting, the complex control mechanisms used increased costs and restricted the acceptance of micro-inverters. Complex and cost-effective IC and processor-based solutions can handle the logic control of micro inverter designs. Various voltage controllers and regulators also provide complementary solutions for solar panel DC output power generation.

The inverter plays an important role in the photovoltaic grid-connected system design. It can convert the solar energy into DC energy and then invert it to the single-phase AC energy that can be applied by various devices. The micro inverter technology means the technology of directly connecting inverter with single PV module. Each PV module can be equipped with an inverter that can realize AC-DC conversion and can track the maximum power point. It can directly convert the power generated by PV module into the AC energy so that it can realize AC load purpose or it can be transmitted to the power grid.

In the solar PV grid tie system, the power of photovoltaic module is related to the inverter. The power matching between PV modules and solar grid tie inverters is not in a relationship of 1:1 fixed ratio, so it needs to be considered comprehensively based on the specific conditions of the project. The main influencing factors include irradiance, system loss, component installation angle, efficiency and life span of the on grid inverter, etc.

Inductor heating is one of the common faults in the use of sine wave inverters. There are two problems resulting to inductor heating: excessive loss on the inductor and poor heat dissipation conditions. The best way to solve the serious problem of heating is to start from the perspective of loss (inductance loss and magnetic core loss).

Centrifugal pump is a pumping machine that uses the centrifugal movement of water to work. Its basic components are a high-speed rotating impeller and a fixed snail-shaped pump casing. Generally, centrifugal pumps have several (usually 4-12) impellers with backward curved blades fastened to the pump shaft, and the impeller is driven by the motor to rotate at a high speed along with the pump shaft.

Do you accept to receive a quote for installing a new bathroom in your house via phone call without the installer visit to your house? Of course, the answer is No. That is same like installing a solar photovoltaic system on your house roof, it’s a must for the solar installer to come the house and check/inspect all your private circumstances and conditions, and absolutely not sufficient to get a quote via phone or internet email.

Inverter refers to a device that converts DC power (such as storage battery) into AC power (usually 220V, 50Hz sine wave). Grid tie inverters are generally used in the system of large-scale solar photovoltaic power stations. Many parallel photovoltaic strings are connected to the DC input of the same centralized inverter. The off grid inverter can work independently after leaving the grid, which is equivalent to forming an independent small grid. This article will introduce on grid inverters and off grid inverters, discuss the working principles of off grid inverters and on grid inverters, as well as their differences.

As to the optimization of the efficiency and reliability for solar photovoltaic system, a rather new means is to use the micro inverter, which shall be connected to each solar panel. Equipping a separate micro inverter for each solar panel can make the system adapt to changing loads and weather conditions, thereby providing the best conversion efficiency for a single panel and the entire system. The micro-inverter architecture can also simplify wiring, which means lower installation costs. By making consumer solar power systems more efficient, the time required for the system to get back the initial investment in solar technology will be reduced.

Inverter is commonly used in the industrial field and its main function is to convert the current in a certain way. Transformer is a device that can change the AC voltage based on the electromagnetic induction principle. It is mainly composed of primary coil, secondary coil and iron core (magnetic core). To make it easier to understand the inverter, hereby the difference between inverter and transformer will be discussed.

As the energy constraint becomes increasingly evident, the solar PV power generation system attracts growing attention. The direct current generated by solar cells and wind-powered generators should be inverted by inverters before being combined to the grid. Therefore, the design of solar on grid inverters determines whether the solar PV system will operate reasonably, efficiently, and economically. The control circuit, signal gathering circuit, and the switching tube drive circuit of solar on grid inverters need different adaptive power supplies. Thus an independent power supply should be provided for powering these circuits. The voltages of the designed auxiliary power supplies include +15V, -15V, and +5V. A single-ended flyback DC/DC topographical structure is adopted, with stable and reliable operation.

Solar panel delamination: This phenomenon occurs when the bond between the solar panel glass on the front, and plastic on the rear is disconnected, because this will let the air and moisture to creep internally in the solar panel causing corrosion, and soon failure. Bond disconnection is resulted from using bad plastic materials with low thermal characteristics, or non-clean plastic / glass or using inferior manufacturing machine with poor pressure and temperature.

The AC voltage overrange is the most common failure of the solar inverter connected with the PV grid system. This is because the grid voltage is not constant and it will change with the changing of the load and current. At the same time, the output voltage of the inverter will be affected by the grid voltage. When the grid encounters abnormal situation, the inverter power supply shall be stopped to avoid more serious damage on the grid.