In the cold winter, the photovoltaic off grid inverter installed outdoors does not have insulation measures, so what does the inverter rely on to survive the winter?

In winter, will the inverter not work because of low temperature?

  • Xindun
  • December 14, 2020

As the weather gets colder and colder, the way of winter in the north and South has been relished.

In the cold winter, the photovoltaic off grid inverter installed outdoors does not have insulation measures, so what does the inverter rely on to survive the winter?

The main function of the photovoltaic inverter is to convert the direct current from the photovoltaic modules into alternating current. It is a power electronic product. The main components are structural parts and electronic devices. The structural parts are not afraid of low temperature. The electronic devices have resistance, capacitance, inductance, relay, display screen, fan, power switch tube, sensor, CPU. Chips, and so on, each component has different low-temperature performance. The low temperature of the inverter depends on these components.

In winter, will the inverter not work because of low temperature?

The display temperature is -30 to 80 degrees.
LCD liquid crystal display, people are most worried about at low temperatures, liquid crystals will not freeze to solid state like water, this concern is redundant, mobile phone screen is liquid crystal, can also be used at minus 40 degrees, photovoltaic inverter STN-LCD, front and rear transparent conductive glass, operating temperature in - 30 ~ 80 degrees Celsius, storage temperature is - 3 5-80 degrees centigrade. At low temperatures, there is no need to worry about LCD screens.

The working temperature of electrolytic capacitor is -30 to 105 degrees.
Because of the presence of electrolyte in electrolytic capacitors, people are also worried about freezing at low temperatures, in fact, the electrolyte will not freeze at minus 40 degrees. However, the conductivity of the electrolyte decreases with the decrease of temperature, which leads to the increase of the electrolyte impedance and therefore the increase of the impedance. The work below the temperature limit will not damage the capacitor, especially when the inverter is running, when the current flows through the device, the heat generated will increase the temperature of the capacitor, making it far greater than the ambient temperature, so that the capacitor can maintain the operation of the equipment.

Because of the characteristics of the dielectric material of thin film capacitor, the ESR value of thin film capacitor is low, so its calorific value is very low. Thin film capacitors can work at 50 degrees below zero, the capacity is not affected, there is a wider range of ambient temperature characteristics, which is also the difference between liquid capacitors and solid capacitors, thin film capacitors at low temperature working stability is very good.

The working temperature of the IC chip is -40 to 85 degrees.

The chip is an integrated circuit made by means of technology on semiconductor substrate. The performance of semiconductors is not invariable, but temperature is an important factor affecting semiconductor chips. With the increase or decrease of temperature, the conductivity, limiting voltage, limiting current, and switching characteristics of semiconductors are greatly changed, and these parameters may cause the external characteristics of semiconductors. For example, a chip at room temperature can withstand 1.4 V voltage, temperature is too high, may not withstand, leading to semiconductor breakdown, causing chip damage, low temperature caused by 1.4 V can not open its internal semiconductor switch caused by its failure to work properly, the inverter control chip DSP, ARM and CPLD, and there are very much. Multi-optical coupler, op-amp, memory and so on, these IC chips operating temperature is - 40 ~85 ~C, storage temperature can be lower, so do not worry about IC chips can not work at low temperature, but some of the op-amp may drift at low temperature, will cause errors in temperature, voltage, current testing.

The working temperature of the power module is -40 to 125 degrees.
The operating temperature range of the power module is a very important parameter. Temperature and heat dissipation are very important for the reliable and effective operation of the system. The temperature range of the power module is between - 40 and - 125 C, mainly for fear of high temperature, low temperature has no effect on the power module, and once the inverter is running, the temperature of the power module will rise rapidly.

The working temperature of the cooling fan is -10 to 70 degrees.
The working temperature of the fan is generally between - 10 - 70 degrees. It may not work at low temperature. However, the main function of the fan is to dissipate heat, and it does not need to work at low temperature. Therefore, it is necessary to select an inverter with intelligent air cooling. The fan will not start until a certain temperature.

Current sensor is the most critical component of inverter. Its measurement accuracy and linear error will directly determine the hardware efficiency. The manufacturers that do better in current sensor are LEM of Switzerland, VAC of America, Tamura of Japan, etc. There are two kinds of open-loop and closed-loop. Open-loop current sensor is generally voltage-type, small volume and weight. Light, no insertion loss, low cost, linear precision 99%, total measurement error about 1%, closed-loop current sensor, wide bandwidth, high precision, fast response time, strong anti-interference ability, linear precision 99.9%, total measurement error 0.4%. Closed-loop current sensor operating temperature between - 40 - 85 degrees, open-loop current sensor operating temperature between - 10 - 80 degrees, so in the northern low temperature environment, it is recommended to use closed-loop sensor.

The key components of the inverter can work at minus 30 degrees, which can ensure the normal operation of the inverter. The cable and current sensor should choose the type of low-temperature-resistant. The Guriwatt MAX60-80kW inverter has the function of SVG. It can output reactive power and improve the power factor in the absence of sunlight, so it can work 24 hours. And as long as the inverter is working, the temperature will rise.