CN103986183B - A kind of grid-connected control system - Google Patents

Abstract

The present invention relates to the field of photovoltaic power generation, in particular to a photovoltaic grid-connected control system, comprising: a photovoltaic module; an inverter; an AC load and a power grid, which receives sinusoidal alternating current delivered by the inverter, and a transformer is arranged between the power grid and the AC load ; DSP controller, its input terminal is electrically connected with the output terminal of the inverter through the voltage sampler, the output terminal of the DSP controller is respectively connected with the AC load and the power grid, and the voltage sampler collects the sinusoidal alternating current delivered by the inverter in real time Voltage value, and the collected voltage value is sent to the DSP controller, the DSP controller compares the voltage value delivered by the voltage sampler with the rated voltage value required by the AC load, and controls the AC load and the power grid through multiple function switching switches connectivity. The invention transmits a corresponding voltage according to the requirement of the AC load, minimizes the damage to the AC load caused by the transmission voltage being too high or too low, and prolongs the service life of the AC load.

Description

A photovoltaic grid-connected control system

technical field

The invention relates to the field of photovoltaic power generation, in particular to a photovoltaic grid-connected control system.

Background technique

The photovoltaic grid-connected power generation system is that the solar photovoltaic power generation system is connected to the conventional power grid to jointly undertake the power supply task. When there is sunlight, the inverter inverts the direct current generated by the photovoltaic system into sinusoidal alternating current, and the generated alternating current can be directly supplied to the alternating current load, and then the remaining electric energy is input into the grid, or all the generated electric energy is directly integrated into the grid. When there is no sun, all load electricity is supplied by the grid. Since the light intensity is changing all the time, the light energy received and utilized by the photovoltaic system is also changing, so the amount of electric energy generated is not fixed, and the voltage required for the normal operation of the AC load is certain. If the photovoltaic system All the generated electric energy is directly supplied to the AC load, which may cause varying degrees of damage to the AC load due to excessively high or low voltage, and shorten the service life of the AC load.

Contents of the invention

In view of the above technical problems, the present invention designs and develops a photovoltaic grid-connected control system, the purpose of which is to be able to monitor the voltage delivered by the inverter in real time, and deliver a corresponding voltage according to the needs of the AC load, so as to minimize the damage caused by excessive transmission voltage. High or too low damage to the AC load, prolong the service life of the AC load.

The technical scheme provided by the invention is:

A photovoltaic grid-connected control system, comprising:

Photovoltaic modules, which convert the received solar radiation energy into high-voltage direct current through high-frequency direct current;

an inverter, which inverts the high-voltage direct current output by the photovoltaic module into a sinusoidal alternating current;

AC load and grid, which receive the sinusoidal AC power delivered by the inverter, and a transformer is arranged between the grid and the AC load;

DSP controller, its input end is electrically connected with the output end of described inverter through the voltage sampler, the output end of described DSP controller is respectively connected with described AC load and grid electricity, and described voltage sampler collects all in real time The voltage value of the sinusoidal alternating current delivered by the inverter, and the collected voltage value is sent to the DSP controller, and the DSP controller compares the voltage value delivered by the voltage sampler with the required value of the AC load. The rated voltage value is compared, and the connection between the AC load and the power grid is controlled through multiple function switching switches.

Preferably, in the photovoltaic grid-connected control system, if the voltage value delivered by the voltage sampler is less than the rated voltage value required by the AC load, the connection between the DSP controller and the AC load The first function switching switch is connected, and the second function switching switch between the DSP controller and the power grid and the third function switching switch between the power grid and the AC load are turned on at the same time, and the transformer is controlled by the DSP Under the action of the AC load, the difference between the rated voltage value required by the AC load and the voltage value delivered by the voltage sampler is delivered to the AC load; if the voltage value delivered by the voltage sampler is greater than the AC load required rated voltage value, connect the first function switching switch between the DSP controller and the AC load, and simultaneously turn on the second function switching switch between the DSP controller and the grid, Disconnect the third function switching switch between the grid and the AC load, and deliver the excess voltage to the grid; if the voltage value delivered by the voltage sampler is equal to the rated voltage value required by the AC load, the The first function switching switch between the DSP controller and the AC load is connected, and the second function switching switch between the DSP controller and the grid and the third function switching between the grid and the AC load are disconnected at the same time switch.

Preferably, in the photovoltaic grid-connected control system, the first to third function switching switches are mechanical switches or electronic switches.

Preferably, in the photovoltaic grid-connected control system, the photovoltaic module includes 40-50 solar cells, and the solar cells are packaged in the frame.

Preferably, in the photovoltaic grid-connected control system, every five solar cells are connected in series to form a first solar battery group, every two first solar battery groups are connected in parallel to form a second solar battery group, and every two second The solar cell groups are connected in series to form a third solar cell group, and the third solar cell groups are connected in parallel to form the photovoltaic module.

In the photovoltaic grid-connected control system of the present invention, the voltage sampler collects the voltage value of the sinusoidal alternating current delivered by the inverter in real time, and transmits the collected voltage value to the DSP controller, and the DSP The controller compares the voltage value delivered by the voltage sampler with the rated voltage value required by the AC load, and controls the first function switch, the second function switch and the third function switch according to the difference between the two. The function switches the connection of the switch, so as to realize the real-time monitoring of the voltage delivered by the inverter, and transmit the corresponding voltage according to the needs of the AC load, input the excess voltage generated by the photovoltaic module into the grid, and use the grid to make up for the shortage of the photovoltaic module To support the voltage difference required for the normal operation of the AC load, minimize the damage to the AC load caused by the transmission voltage being too high or too low, and prolong the service life of the AC load. The solar cells of the photovoltaic module are connected multiple times in series and multiple times in parallel, which improves the utilization rate of solar energy of the photovoltaic module.

Description of drawings

Fig. 1 is a schematic diagram of a photovoltaic grid-connected control system according to the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings, so that those skilled in the art can implement it with reference to the description.

As shown in Figure 1, the present invention provides a photovoltaic grid-connected control system, including:

Photovoltaic modules, which convert the received solar radiation energy into high-voltage direct current through high-frequency direct current, a solar cell can only generate a voltage of about 0.5V, which is far lower than the voltage required for actual use. In order to meet the required voltage for actual use, it is necessary to The solar cells are connected into modules;

Inverter, which inverts the high-voltage direct current output by the photovoltaic module into sinusoidal alternating current. Since the solar cell emits direct current, and the general load is an alternating current load, an inverter is required to invert the high-voltage direct current output by the photovoltaic module is a sinusoidal alternating current;

An AC load and a power grid, which receive the sinusoidal AC power delivered by the inverter, a transformer is arranged between the grid and the AC load, and the transformer reduces the voltage output by the power grid and then sends it to the AC load;

DSP controller, its input end is electrically connected with the output end of described inverter through the voltage sampler, the output end of described DSP controller is respectively connected with described AC load and grid electricity, and described voltage sampler collects all in real time The voltage value of the sinusoidal alternating current delivered by the inverter, and the collected voltage value is sent to the DSP controller, and the DSP controller compares the voltage value delivered by the voltage sampler with the required value of the AC load. The rated voltage value is compared, and the connection between the AC load and the power grid is controlled through multiple function switching switches to ensure the rated voltage required for the normal operation of the AC load.

In the photovoltaic grid-connected control system, if the voltage value delivered by the voltage sampler is less than the rated voltage value required by the AC load, the first function between the DSP controller and the AC load The switching switch is connected, and the second function switching switch between the DSP controller and the grid and the third function switching switch between the grid and the AC load are connected at the same time, and the transformer is under the action of the DSP controller Step down the output voltage of the power grid, and deliver the difference between the rated voltage value required by the AC load and the voltage value delivered by the voltage sampler to the AC load, so as to ensure the normal operation of the AC load. voltage; if the voltage value delivered by the voltage sampler is greater than the rated voltage value required by the AC load, connect the first function switching switch between the DSP controller and the AC load, and turn on at the same time The second function switching switch between the DSP controller and the power grid disconnects the third function switching switch between the power grid and the AC load, and sends excess voltage to the power grid to reduce the impact of excessive voltage on the AC load. Damage caused by the load; if the voltage value delivered by the voltage sampler is equal to the rated voltage value required by the AC load, connect the first function switching switch between the DSP controller and the AC load, and at the same time Disconnecting the second function switching switch between the DSP controller and the grid and the third function switching switch between the grid and the AC load.

In the photovoltaic grid-connected control system, the first to third function switching switches are mechanical switches or electronic switches.

In the photovoltaic grid-connected control system, the photovoltaic module includes 40-50 solar cells, and the solar cells are packaged in a frame, and the frame is a stainless steel frame, an aluminum frame or a non-metal frame.

In the photovoltaic grid-connected control system, every five solar cells are connected in series to form a first solar cell group, every two first solar cell groups are connected in parallel to form a second solar cell group, and every two second solar cell groups are connected in series into a third solar battery group, and the third solar battery group is connected in parallel to form the photovoltaic module.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (1)

1. a grid-connected control system, is characterized in that, comprising:

Photovoltaic module, its solar radiation energy by reception changes into high voltage direct current through high-frequency direct-current;

Inverter, its high voltage direct current inversion by described photovoltaic module output is sinusoidal ac;

AC load and electrical network, it receives the sinusoidal ac that described inverter is carried, electrical network and AC load itBetween be provided with transformer;

Dsp controller, its input is electrically connected with the output of described inverter by voltage sample device, described inThe output of dsp controller is electrically connected with described AC load and electrical network respectively, and described voltage sample device is adopted in real timeCollect the magnitude of voltage of the sinusoidal ac of described inverter conveying, and the magnitude of voltage collecting is sent to described DSPController, magnitude of voltage and described AC load that described dsp controller is carried described voltage sample device are requiredLoad voltage value compare, by the company of AC load described in the control of multiple function change-over switch and electrical networkLogical;

If the magnitude of voltage that described voltage sample device is carried is less than the required load voltage value of described AC load, willThe first function change-over switch between described dsp controller and described AC load is communicated with, described in connecting simultaneouslyThe second function change-over switch between dsp controller and described electrical network and described electrical network and described AC loadBetween the 3rd function change-over switch, described transformer under the effect of described dsp controller by described interchangeThe difference of the magnitude of voltage that the required load voltage value of load is carried with described voltage sample device is delivered to described interchangeLoad; If the magnitude of voltage that described voltage sample device is carried is greater than the required load voltage value of described AC load,The first function change-over switch between described dsp controller and described AC load is communicated with, connects institute simultaneouslyState the second function change-over switch between dsp controller and described electrical network, disconnect described electrical network and exchange with describedThe 3rd function change-over switch between load, is delivered to unnecessary voltage in electrical network; If described voltage sample deviceThe magnitude of voltage of carrying equals the required load voltage value of described AC load, by described dsp controller and instituteThe first function change-over switch of stating between AC load is communicated with, and disconnects described dsp controller and described electricity simultaneouslyThe 3rd function between the second function change-over switch between net and described electrical network and described AC load is switchedSwitch;

Wherein, the described first to the 3rd function change-over switch is mechanical switch or electronic switch;

Described photovoltaic module comprises 40～50 solar cells, and described solar cell package is in frame;

Every 5 of described solar cell is connected into the first solar battery group, every two the first solar battery groupAnd be unified into the second solar battery group, every two the second solar battery group are connected into the 3rd solar battery group,Described the 3rd solar battery group is also unified into described photovoltaic module.