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In solar inverters, there are parasitic inductances which are harmful to power switching devices. They are stray inductances. Stray inductance will increase with the increase of current, the size of connecting wire and the distance. In the process of IGBT switching off, voltage spikes will occur due to the sharp decrease of current. There are several risks: First, IGBT will be overvoltage. In the case of high current, it is necessary to use IGBT with higher voltage level, but the device with higher voltage level will lose more and cost more. Secondly, voltage spike will also bring additional switching loss, which will reduce system efficiency and increase cost.

Reasonable design of interconnected conductors of inverters to reduce the inductance and its influence is very important to improve the reliability and operation performance of inverters. Inverters generally adopt the following three methods to reduce stray inductance:

1.Using stacked bus

The positive and negative terminal directions of capacitors are consistent with the current directions, and the distance between capacitors and power devices is as short as possible, the distance between the positive and negative poles of the stacked bus is as short as possible. The distributed inductance of the line is reduced by the parallel distribution of the positive and negative electrodes, which reduces the reverse peak voltage at both ends of the power element, reduces the requirement of the power device for the voltage protection absorption circuit, improves the reliability and stability of the operation of the power device, and improves the integration of the circuit so as to facilitate maintenance.

2.Using high frequency absorption thin film capacitance

Absorbing capacitors play a similar role in the circuit to low-pass filters, which can absorb the peak voltage. Usually used in insulated gate bipolar transistor (IGBT), eliminating the peak voltage caused by busbar stray inductance, avoiding the damage of insulated gate bipolar transistor.

3.Using power module

The power module uses special technology to integrate and package multiple components together, which ensures the shortest distance between components and reduces the distributed inductance of the circuit. To reduce stray inductance, medium power group series inverters usually adopt the scheme of power module and centralized inverters, usually adopt the scheme of stacked bus and absorbing thin film capacitors.

REVO-E 3-5.5kW Hybrid Solar Energy Storage Inverters

1. PV and utility power take the load at same time ( can setting ).
2. Output power factor PF=1.0
3. On/Off grid with energy storage.
4. AC charging and AC output time setting.
5. Charging voltage and charging current timing.
6. External Wi-Fi device optional.
7. Connected with battery optional.
8. Wide PV input range 120-450VDC.
9. MAX PV Array Power 4500W.

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Usually the harmonic current is proportional to the working current of the harmonic source equipment. Dynamic harmonic filter, which measures load harmonic current by controller, controls bi-directional thyristor zero-crossing trigger, realizes dynamic harmonic filtering and reactive power compensation for non-linear load, and has no impact, inrush and transition during switching process.

1.Automatically tracking the harmonic of compensating change has high controllability and fast responsiveness. Compensation performance is not affected by the frequency fluctuation of power grid, and filtering characteristics are not affected by system impedance, which can eliminate the risk of resonance with system impedance.

2.It can not only control harmonics, but also compensate reactive power, restrain flicker and improve power factor. It can independently compensate for a single harmonic source or centrally compensate for multiple harmonic sources. The specified sub-harmonics are eliminated when harmonics are eliminated, and no energy storage elements are needed when reactive power is compensated.

3.Full-bridge PWM converter is used to generate compensating current, and power devices are operated by the third generation IGBT with high frequency switching mode. IGBT devices and drive and protection circuits are equipped with success rate unit module, which makes the converter small in size, high in efficiency and high in reliability.

4.The current detection technology based on instantaneous reactive power is used to detect harmonic current. The dynamic compensation of harmonic current is realized by multiple instantaneous current tracking control. Because of the current control, the harmonic can be compensated to the maximum extent without overload.

5.TSF+TSC can form a dynamic harmonic and reactive power compensator. It is suitable for situations with high load harmonic content, low power factor and large load fluctuation. It has dual functions of TSF and TSC, and can effectively realize dynamic harmonic suppression and reactive power compensation.

6.The high-speed detection and operation of DSP ensures the accuracy and effectiveness of harmonic detection and compensation control; it also has intelligent monitoring function, flexible device operation, clear operation parameters and working status, automatic fault diagnosis; and it can expand communication excuse and monitor by PC.

SOROTEC Three-phase Balance Active Harmonic Filter(AHF)

Meeting users’ requirements:
– PF=0.99 and THDi < 5%
– Compensation for 2- to 50-order harmonics
– Capacitive and inductive reactive power compensation
– Three-phase unbalance co

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The common structure of on grid solar power generation system includes centralized, series, multi-series and AC modules. In centralized, series and multi-series systems, there are series and parallel solar cell modules, so the maximum power point tracking of the system is aimed at the whole series-parallel solar cell array, which can not take into account each solar cell array in the system. The utilization of single solar cell array is low, the system has poor ability to resist local shadows, and the system expansion flexibility is not enough. The solar on grid micro-inverters are connected with a single solar cell module, which can directly convert the DC output of the solar cell module into AC and transmit it to the grid. They have the following advantages:

1.It ensures that each solar cell module runs at the maximum power point, and has a strong ability to resist local shadows.

2.By integrating micro-inverters with solar cell modules, can realize modular design, plug-and-play and hot plug-and-play, while the system expansion is simple and convenient.

3.Micro-inverters do not occupy installation space independently. Distributed installation is easy to configure. They can make full use of space and adapt to different installation directions and angles.

4.The system has high redundancy and reliability, and the failure of a single module will not affect the whole system.

SSP3115C 1-12KVA Low Frequency Pure Sine Wave Inverter with MPPT Solar Charge Controller

1. Built-in MPPT solar controller
2. Pure sine wave output
3. The charging current is big up to 85 Amp
4. Output power factor:s 0.9-1
5. Well accept generator’s output
6. Full automatical and silent operation
7. Automatically transfer between battery and line modes
8. Microprocessor control guarantees high reliability
9. Remote control function
10. Four-steps intelligent charging control to recharging time
11. Bypass and bypass voltage regulation function
12. With AVR function (optional)
13. Mains/solar output priority level for the customer to choose .
14. Mains/solar/ mains & solar charging three mode of priorities for the customer to choose .
15. Battery type can choose from 0-9

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A device used to filter one or more harmonics in power system; most of its structures are composed of inductors, capacitors and resistors, i.e. passive harmonic filters, which also serve as reactive power compensation; the emerging filtering technology also includes active harmonic filters.

It is used to filter harmonics in power system with voltage less than 1000 volts, such as harmonics generated by six-pulse rectifier, also known as harmonic generator.

Based on the principle of electromagnetic induction and reactor, a filter compensation system is composed of high performance filter capacitors connected in series with high linearity filter devices to compensate reactive power while absorbing the main harmonic components of the system. By integrating dynamic reactive power compensation and filtering functions, it can quickly follow the load changes, and has three main functions: restraining current fluctuation, absorbing harmonics of power grid and compensating reactive power.

Three-phase Balance Active Harmonic Filter(AHF)

– PF=0.99 and THDi < 5%
– Compensation for 2- to 50-order harmonics
– Capacitive and inductive reactive power compensation
– Three-phase unbalance co

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Building Integrated PV(BIPV) is a new concept of solar power generation. Simply speaking, solar photovoltaic power generation square array is installed on the outer surface of the building envelope to provide power. According to the different ways of combining photovoltaic array with buildings, building Integrated PV can be divided into two categories: one is the combination of photovoltaic array and buildings. The other is the integration of photovoltaic array and building, such as photoelectric tile roof, photoelectric curtain wall and photoelectric lighting roof. In these two ways, the combination of photovoltaic arrays and buildings is a common form, especially with the roof of buildings. Because the combination of photovoltaic array and building does not occupy additional ground space, it is the best installation method of photovoltaic power generation system widely used in cities, so it attracts much attention. The integration of photovoltaic arrays and buildings is an advanced form of BIPV, which requires higher requirements for photovoltaic modules. Photovoltaic modules should not only meet the functional requirements of photovoltaic power generation, but also take into account the basic functional requirements of buildings.

According to the different ways of combining photovoltaic arrays with buildings, building Integrated PV can be divided into two categories:

1.The combination of photovoltaic array and architecture.

In this way, the photovoltaic array is attached to the building, which acts as the carrier of the photovoltaic array and plays a supporting role. The further combination of photovoltaic arrays and buildings is the integration of photovoltaic devices and building materials. The general building envelope surface uses paint, decorative tile or curtain wall glass, the purpose is to protect and decorate the building. If photovoltaic devices are used instead of some building materials, that is, photovoltaic modules are used to make roofs, exterior walls and windows of buildings, so that they can be used as building materials as well as power generation, which is perfect. For frame structure buildings, the whole envelope structure can be made into photovoltaic arrays, and appropriate photovoltaic modules can absorb both direct sunlight and reflected sunlight. At present, a large-scale color photovoltaic module has been developed, which can achieve the above objectives and make the appearance of the building more attractive.

2.The integration of photovoltaic array and building.

This way is that photovoltaic modules appear in the form of a building material, and photovoltaic arrays become an integral part of the building.

SPS3115C Series 1-10KVA outdoor solar system

1.Pure sine wave inverter
2.Built-in MPPT solar charge controller
3.Could be built-in battery
4.Protection degree:IP55
5.Configurable input voltage range for home appliances and personal computers via LCD setting
6.Configurable AC/Solar Charger priority via LCD setting
7.Compatible to mains voltage or generator power
8.Auto restart while AC is recovering
9.Overload/Over temperature/short circuit protection
10.Configurable battery charging current based on applications via LCD setting

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