ST STEVAL-ISV002V2 User Manual Download Page 1 | Manualshive

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ST STEVAL-ISV002V2 User Manual Download Page 1

February 2011

Doc ID 18125 Rev 1

1/19

UM1016

User manual

Getting started with the STEVAL-ISV002V2, 3000 W

photovoltaic converter for grid connected applications

Introduction

This document describes the procedure and steps to follow in order to correctly operate the
3 kW STEVAL-ISV002V2 photovoltaic converter. This system consists of an isolated DC-DC
converter and a full bridge inverter used to deliver sinusoidal current at 50 Hz to the grid.
The system operates with input voltages in the range of 200 V to 400 V and is tied to the grid
at 230 Vrms, 50 Hz, through an LCL filter. The demonstration board is provided with a fully
digital control algorithm, including power management for grid-connected operation and
MPPT (maximum power point tracking) algorithm. This has been implemented on a
dedicated control board, equipped with the latest generation 32 bit STM32F103ZE
microcontroller.

Figure 1.

3 kW PV system image

www.BDTIC.com/ST

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Summary of Contents for STEVAL-ISV002V2

Page 1: ...l bridge inverter used to deliver sinusoidal current at 50 Hz to the grid The system operates with input voltages in the range of 200 V to 400 V and is tied to the grid at 230 Vrms 50 Hz through an LCL filter The demonstration board is provided with a fully digital control algorithm including power management for grid connected operation and MPPT maximum power point tracking algorithm This has bee...

Page 2: ...Contents UM1016 2 19 Doc ID 18125 Rev 1 Contents 1 System description 4 2 Revision history 18 www BDTIC com ST ...

Page 3: ...Figure 10 First screen shot shown on the LCD display at startup 10 Figure 11 Description of the joystick commands 10 Figure 12 Closed loop open loop selection window 11 Figure 13 Open loop screen shot with control state in Off 11 Figure 14 Screen shot with control loop state in start 12 Figure 15 DC DC converter control window 12 Figure 16 DC AC converter control window 13 Figure 17 LCD display sc...

Page 4: ... DC DC converter and the high frequency HF transformer are also placed on the main power board The multi output power supply board and the control board are connected to the main power board by means of 34 pin connectors The connection disconnection of these PCBs is very easy This type of connection was chosen to allow separate debug and characterization of each board independently from the others...

Page 5: ...gure 3 Description of the STEVAL ISV002V2 main parts Figure 3 shows a more detailed description of the hardware implementation according to the nomenclature used above The main power board is highlighted in yellow and clearly shows the way it hosts two ancillary boards the multi output power supply board and the control board with STM32F103ZE They are both highlighted in red in Figure 3 Also the o...

Page 6: ... screw terminal connectors are highlighted The filter inductors are connected to J8 placed on the main power board and to J7 which is placed in the output sensing and relay board The coupling reactor is also connected to the output sensing and relays board through J9 It is important to underline that while the filter inductors have the two wires connected between J7 and J8 both the wires of the co...

Page 7: ...o be acquired through the ADCs In particular on the microcontroller board J14 is used to connect the wire carrying the signal proportional to the input DC current The second terminal of this wire is connected on the input current sensing board The wire carrying the signal proportional to the line voltage is connected to J11 at one end on the microcontroller board and on the other end to J15 which ...

Page 8: ...o the 3 way screw terminal connector called VDC on the output sensing board The 15 V is also used to obtain the 5 V supplying the Hall effect current sensor The relay coil is supplied with 24 V provided by the multi output flyback of the power supply board and running on a multi core shielded wire connected between the 24 V connector of the power supply board and J11 on the output sensing board Th...

Page 9: ...ering power to a suitable external load The open loop function and hardware configuration allows also to independently test both the DC DC converter and the DC AC converter In this case connector J9 shown in Figure 9 can be used to either connect an electrical load when testing the DC DC converter or to connect a DC power supply when testing the DC AC inverter Figure 9 Input and output power conne...

Page 10: ...stick that can be used to scroll the menu for functions included in the firmware The joystick has five commands as detailed in Figure 11 Figure 11 Description of the joystick commands The test procedure detailed below can be followed in order to test the system with the open loop control firmware 1 Connect a suitable electrical load to connector J7 Keep the filter inductors wire connected on J7 as...

Page 11: ...trol state in stop Figure 13 Open loop screen shot with control state in Off 3 Connect a DC power supply and set the input voltage The input voltage value in open loop operation can be set arbitrarily making sure not to exceed the allowed maximum input voltage Please note that no protections are enabled and no regulation of input or output voltages and currents is active 4 Push the joystick to ena...

Page 12: ...highlighted The screen shot in Figure 15 appears Figure 15 DC DC converter control window 6 Move the joystick right to increase the phase shift The incremental step is highlighted in the last string of characters 1 778 us in Figure 5 and can be modified The power output increases proportionally to the phase shift 7 The amount of power delivered to the electrical load depends also on the value of t...

Page 13: ... are discharged on the electrical load Closed loop operation The closed loop operation allows to connect the system to the grid and to start current injection at 230 V and 50 Hz Before realizing the first grid connection it is advised to follow the procedure below This procedure allows to check in a safe way for any potential problems that might affect the demonstration board without the risk of s...

Page 14: ...ion Verify that the AC current AC_C offset value is between 2 3 and 2 5 V and the AC voltage offset value AC_V is between 1 8 V and 1 9 V Navigate the display to again enter the closed loop string Set the DC input voltage to 170 V with the output disabled and connect it to J7 on the power board Do not enable the DC source while setting the voltage value Enable the DC source Push the joystick butto...

Page 15: ...erated If two voltage probes are placed on the inverter output Figure 20 across the capacitor of the LCL filter and on the grid connector it is possible to see on the scope a sinusoidal voltage slightly lagging the grid voltage and having a higher peak value Figure 20 Voltage probe placement to compare inverter generated voltage and gird voltage If the grid voltage is in the proper range 190 265 V...

Page 16: ... function navigating the display When the calibration function is executed the display shows a grid current offset of about 2 5 V and a grid voltage offset of about 1 8 V Do not start the closed loop operation if the offset values are not close to the values specified above Navigate the display to the closed loop string Set the DC input voltage to 170 V disabled and connect it to J7 power board En...

Page 17: ...t it is possible to fine tune all the control loop PI regulators by navigating the display menu Figure 21 The PLL PI parameters can be modified only by acting on the firmware Figure 22 Control parameters tuning Always monitor the grid current waveform THD and power factor when attempting to modify any of these parameters Note that modifying any of these parameters can make the control loop unstabl...

Page 18: ...Revision history UM1016 18 19 Doc ID 18125 Rev 1 2 Revision history Table 1 Document revision history Date Revision Changes 09 Feb 2011 1 Initial release www BDTIC com ST ...

Page 19: ...S OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION OR INFRINGEMENT OF ANY PATENT COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE ST PRODUCTS ARE NOT RECOMMENDED AUTHORIZED OR WARRANTED FOR USE IN MILITARY AIR CRAFT SPACE LIFE SAVING OR LIFE SUSTAINING APPLICATIONS NOR ...

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