Preface
Resolute is a module-level power electronics provider, including microinverters, module-level shutdowns and energy storage systems. This time, the charging head network found a photovoltaic grid-connected microinverter YC250A launched by Yuneng Technology, which has a maximum output power of 250W and an output voltage of 220V. The maximum input voltage of DC is 55V, supports 22-45V maximum power tracking, and the maximum input current is 12A.
The inverter housing is made of metal and has IP65 protection. There are screws on the side of the inverter to fix the mounting bracket. The bottom of the inverter is the DC input wiring, and there are connecting wires on both sides for AC output and communication functions. There is also an indicator light on the side of the fuselage for working status indication. Let's bring the dismantling of this photovoltaic microinverter, and take a look at the internal design and materials.
Appearance of Yuneng YC250A photovoltaic grid-connected microinverter
Yuneng 250W photovoltaic grid-connected microinverter YC250 adopts an all-metal shell, and the connector terminals are also designed with cables, and the overall external style is very different from the YC240 model of Yuneng that has been disassembled by the charging head network before.
The fuselage tends to be square-shaped, with rounded edges, and the surface of the shell is all sprayed with black protective paint.
There is an L-shaped metal fixing plate on the top of the fuselage, which is connected and fixed with the fuselage through hexagon tamper-proof screws.
There is a product nameplate on the back of the fuselage.
Close-up of product parameters
Name: Photovoltaic grid-connected microinverter
Model: YC250A
Maximum DC input voltage: 55VDC
Rated AC voltage: 220VAC
Rated AC current: 1.14A
Rated AC frequency: 50Hz
Output power factor: >0.99
Maximum AC output power: 250W
Maximum DC input current: 12A
Maximum power point tracking range: 22-45VDC
Maximum Efficiency: 95.5%
Total Current Harmonic Distortion: <3%
Protection level: l
Overvoltage Category: III
Degree of protection: IP65
Operating ambient temperature: -40°C to +65°C
Zhejiang Yuneng Technology Co., Ltd
The side of the fuselage is equipped with a blind rivet for fixing, and there is also an indicator light on this side.
Close-up of the indicator.
The connecting terminals on both sides of the fuselage tend to be cylindrical, and they are fixed when connected by knobs at the ends.
A set of connection terminals under the fuselage is a classic snap style that fits suit.
The measured product body length is 158.96mm.
The width is 152.99mm.
The thickness is 29.4mm.
The length of the connecting wire and terminal on one side of the fuselage is about 30cm.
The length of the connecting wire and terminal on the other side is about 80cm.
Finally, the weight of the product was about 1707g.
Dismantling of YC250A photovoltaic grid-connected microinverter
After reading the appearance display of Yuneng's photovoltaic inverter, let's disassemble it and take a look at the internal workmanship and materials.
First of all, the blind rivet on the side of the fuselage is cut, the cover plate is opened, and the internal PCBA module is filled with thermally conductive glue.
The PCBA module is fixed inside the housing with screws.
Remove the PCBA module from inside the aluminum housing.
The front of the PCBA module is at a glance, with the input filter capacitor at the top, two step-up transformers at the bottom, the output filter circuit at the bottom right, and the auxiliary power supply circuit on the left.
The back side is soldered with the main control chip, switch tube, feedback optocoupler and rectifier tube.
Close-up of filter inductor at the input end, chip soldering. On the left side of the inductor is the solar cell input terminal, which is also soldered.
The two filter capacitors are from Chemi-Con and are rated at 63 V 2200 μF.
The other set of filter capacitors has the same specifications.
The current transformer is used to detect the switch current.
Texas Instruments UCD7100 low-side drivers are used for switch tube drives.
Close-up of another current transformer.
Close-up of Texas Instruments UCD7100 drive.
The boost switch is from Infineon, model BSC190N15NS3, NMOS, withstand voltage 150 V, conduction resistance 19 mΩ, and is available in a PG-TDSON-8 package.
The other switch tube is of the same type.
A 5mΩ sampling resistor is used to sense the input current.
Close-up of two step-up transformers.
The film capacitor size is 0.022μF.
The other film capacitor has the same specifications.
The silicon carbide diode is from CREE, the model number is C4D02120E, the withstand voltage is 1200V, and it is available in a TO-252-2 package.
The other SiC diode is of the same model.
The programmable gate array chip is from LATTICE, model number LFE2-12SE-5TN144C.
外置50MHz时钟晶振特写。
The memory is from Winbond, model W25Q32BVSIG, and the capacity is 4MB.
The filtered tantalum capacitor specification is 330μF 10V.
One MCU from Silicon Labs, model C8051F850, is a mixed-signal 8-bit MCU with a built-in 8051 core, a main frequency of 25MHz, and a built-in 8KB Flash and 512B RAM on the chip. The chip has a built-in ADC, DAC and two comparators.
The power master control chip is from onsemi, model number NCP1377, and is used for auxiliary power control.
The LDO regulator chip is from Texas Instruments, model LP2981, the input voltage is 16V, the output voltage is 3.3V, and the output current is 100mA.
Three optocouplers are used to isolate communication.
Close-up of two other 3053 isolated optocouplers.
One MOS transistor from STMicroelectronics, model STB18NM80, NMOS, withstand voltage 800V, conduction resistance 250mΩ.
The other MOS tube is of the same model.
The two thyristors are from STMicroelectronics, silkscreen-printed TN815800, the actual model number is TN815-800B-TR, the specification is 800V 8A, and the package is DPAK.
The safety X2 capacitor is from Xiamen Farah Electronics, and the specification is 0.47μF.
Close-up of a blue varistor.
The filter inductor core is wrapped with tape insulation.
The safety X2 capacitor is from Xiamen Farah Electronics, and the specification is 1μF.
The two fuses are from SCHURT, with a specification of 6.3A 250V.
The other filter inductor has the same specifications.
Close-up of the varistor at the output.
The outputs are connected via connectors.
The blue varistors are from the TDK S14 series.
The safety X2 capacitor specification is 0.22μF.
The common mode inductor is wound with insulated wire.
Close-up of auxiliary power transformer.
One MOS transistor is from Vishay, model SI4848, with a withstand voltage of 150V, a conduction resistance of 70mΩ, and a SOP8 package.
Close-up of the F817A feedback optocoupler.
One transistor model BD238.
Close-up of a two-color LED indicator to indicate the operating status.
One MOS transistor from STMicroelectronics, model number STD10NM65N, is a 650V NMOS with a 430mΩ impedance in a DPAK package.
The other MCU has the same model, which is C8051F850 by Silicon Labs.
The inverter, model CD40106B, from Texas Instruments, is a 6-channel inverter chip with a Schmidt-triggered input.
The isolation chip from Silicon Labs, model Si8610EC, is a dual-channel digital isolator.
IMP706 watchdog chip with power-down detection and power monitoring functions.
The powerline communication chip is from Risecond, model RISE3501, and is used for communication between the inverter and the host.
Close-up of an external 10.000MHz chip crystal oscillator.
A list of all dismantling and a family photo.
Summary of the dismantling of the charging head network
The YC250A PV grid-connected inverter adopts a metal shell, has IP65 protection level, and supports -40~65°C working temperature to meet outdoor applications. The maximum output power of the inverter is 250W and the output voltage is 220V. The maximum input voltage of DC is 55V, supports 22-45V maximum power tracking, and the maximum input current is 12A.
Through dismantling, the charging head network learned that the YC250A inverter of Yuneng Technology adopts a potting process to improve the heat dissipation performance, and the internal PCBA module is fixed inside the aluminum alloy shell by screws. The DC input of the inverter is filtered by Chemi-Con electrolytic capacitors, boosted by Infineon's BSC190N15NS3-G MOS, rectified by CREE C4D02120E silicon carbide diodes at the boost output, and modulated by MOS transistors and thyristors.
Internally, Silicon Lab MCU and Lattice LFE2-12SE-5TN144C programmable gate array chip are used for the whole machine control, and the auxiliary power supply adopts the NCP1377 main control chip, and the Risecom power line communication chip is also used to communicate with the host. The internal materials are reliable in workmanship and can meet the operation of outdoor harsh environments.