CN110456214A - A kind of alone island detection system and its method - Google Patents
A kind of alone island detection system and its method Download PDFInfo
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- CN110456214A CN110456214A CN201910658747.9A CN201910658747A CN110456214A CN 110456214 A CN110456214 A CN 110456214A CN 201910658747 A CN201910658747 A CN 201910658747A CN 110456214 A CN110456214 A CN 110456214A
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
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Abstract
The invention belongs to the fields of isolated island detection, and in particular to a kind of alone island detection system and its method, wherein a kind of alone island detection system includes: control module；Inverter circuit, for generating SPWM waveform；Output signal circuit, for exporting network wave；Comparison circuit, the time difference being used between the zero point moment of the SPWM waveform and the zero point moment of the network wave, and define the SPWM pointer value that the time difference between the zero point moment is the zero point moment；Wherein, whether the SPWM pointer value that the control module detects the zero point moment fluctuates in fixed range.A kind of island detection method, by the SPWM pointer value for detecting the zero point moment, if fluctuated in fixed range, isolated island detection can be effectively achieved.The present invention has many advantages, such as that detectability is strong, current distortion is small, is suitable for more photovoltaic systems.
Description
Technical field
The invention belongs to the fields of isolated island detection, and in particular to a kind of alone island detection system and its method.
Background technique
Isolated island detection is the function of the grid-connected indispensability of photovoltaic system, it is desirable that can quickly detect island state, while again to the greatest extent
Amount reduces the adverse effect to power grid.
Being known as effective method now has: apply voltage positive feedback method, the active power method of perturbation of disturbance for amplitude,
The Active frequency drift method for applying disturbance for frequency applies reactive power disturbance method, the active phase-shifting method etc. of disturbance for phase.This
A little methods can be transferred through software realization and obtain preferable effect, but if technical treatment is bad, the operation that can aggravate DSP is negative
Load, or cause isolated island detection performance not up to standard, or make to export power quality aberration rate increase etc..Sliding formwork frequency deviation method (Slip-
Mode Frequency Shift, SMS) automatic shifting phase method (Automatic Phase Shift, APS) be active phase shift
The Typical Representative of isolated island detection algorithm, island state can be effectively detected out in they, but algorithm and decision logic are more complex, increase
The difficulty that DSP is realized.
To solve the above-mentioned problems, present invention employs a kind of alone island detection system and its methods.
Summary of the invention
It is excellent it is an object of the invention to solve at least the above problems and/or defect, and provide at least to will be described later
Point.
It is a still further object of the present invention to provide a kind of alone island detection systems, realize without DSP, can be realized with single-chip microcontroller
Isolated island detection.
It is a still further object of the present invention to provide a kind of alone island detection systems, influence small, detectability to power quality
Fully meet the standard of isolated island detection.
It is a still further object of the present invention to provide a kind of island detection method, it is strong with detectability, current distortion is small,
Suitable for more photovoltaic systems.
In order to realize these purposes and other advantages according to the present invention, the present invention provides a kind of alone island detection system,
Include:
Control module；
Inverter circuit is connect with the control module, for generating SPWM waveform；
Output signal circuit, one end are connect with the inverter circuit, the other end of the output signal circuit with it is described
Control module connection, for exporting network wave；
Comparison circuit is connect with the output signal circuit and the control module, is used to the SPWM waveform
The zero point moment and the network wave the zero point moment between time difference, and define the time difference between zero point moment
For the SPWM pointer value at zero point moment；
Wherein, whether the SPWM pointer value that the control module detects the zero point moment fluctuates in fixed range.
Preferably, the inverter circuit includes prime push-pull circuit, current rectifying and wave filtering circuit, rear class inverter circuit and LCL
The output end of filter circuit, the prime push-pull circuit is connect with the input terminal of the current rectifying and wave filtering circuit, the rectification filter
The output end of wave circuit is connect with the input terminal of the rear class inverter circuit, the output end of the rear class inverter circuit with it is described
The input terminal of LCL filter circuit connects.
It preferably, further include pre-driver circuitry and post-stage drive circuit, the pre-driver circuitry and the rear class
One end of driving circuit is connect with the control module, the other end of the pre-driver circuitry and the prime push-pull circuit
Other end connection, the other end of the post-stage drive circuit connect with the input terminal of the rear class inverter circuit.
Preferably, the output signal circuit includes current sampling circuit, voltage sampling circuit and network voltage sampling
Circuit, the current sampling circuit, the voltage sampling circuit and the line voltage sample circuit one end with the LCL
The output end of filter circuit connects, the current sampling circuit, the voltage sampling circuit and the line voltage sample circuit
The other end connect with the control module；
Wherein, one end of the line voltage sample circuit is connect with the comparison circuit.
Preferably, the comparison circuit includes comparator, and anode is connect with the line voltage sample circuit, described
The negative terminal of comparator connects 2.5V reference voltage, and the output end of the comparator is connect with the control module.
Preferably, the control module is the MCU of HYM8F028C6 model.
Preferably, further include power supply, connect all the way with the pre-driver circuitry, the another way of the power supply and institute
State control module connection；
Wherein, the input voltage of power supply is 24V, and the voltage all the way of pre-driver circuitry described in the power supply is
12V, the voltage all the way of control module described in the power supply are 5V.
The present invention also provides a kind of island detection methods, which comprises the following steps:
By inverter circuit and output signal circuit, SPWM waveform and network wave are generated respectively；
Come between the zero point moment of SPWM waveform described in comparison and the zero point moment of the network wave by comparing circuit
Time difference, and define the SPWM pointer value that the time difference between zero point moment is the zero point moment；
Whether the SPWM pointer value that control module detects the comparison circuit output fluctuates in fixed range.
Preferably, it is described by comparing circuit come SPWM waveform described in comparison the zero point moment and the network wave
Time difference between the zero point moment, and before defining the SPWM pointer value that the time difference between zero point moment is the zero point moment
Further include:
After the control module captures the zero cross signal of the comparison circuit, SPWM pointer value this moment is remembered, with zero
The SPWM pointer value of point moment relatively after, differ greatly, then by being decreased or increased SPWM pointer value, phase difference reduced, even if institute
State SPWM waveform the zero point moment and the network wave zero point when to be carved with the regular hour poor.
Preferably, the inverter circuit includes prime push-pull circuit, current rectifying and wave filtering circuit, rear class inverter circuit and LCL
The output end of filter circuit, the prime push-pull circuit is connect with the input terminal of the current rectifying and wave filtering circuit, the rectification filter
The output end of wave circuit is connect with the input terminal of the rear class inverter circuit, the output end of the rear class inverter circuit with it is described
The input terminal of LCL filter circuit connects；
The output signal circuit includes line voltage sample circuit, the input terminal of the line voltage sample circuit and institute
The output end connection of LCL filter circuit is stated, an output end of the line voltage sample circuit is connect with the control module,
The another output of the line voltage sample circuit is connect with the comparison circuit；
The comparison circuit includes comparator, and anode is connect with the line voltage sample circuit, the comparator
Negative terminal connects 2.5V reference voltage, and the output end of the comparator is connect with the control module.
Wherein, the control module is the MCU of HYM8F028C6 model.
The present invention is include at least the following beneficial effects:
1, a kind of alone island detection system provided by the invention is realized without DSP, does not need complicated mathematical computations, is used
Isolated island detection can be realized in single-chip microcontroller.
2, a kind of alone island detection system provided by the invention, small on power quality influence, detectability fully meets orphan
The standard of island detection.
3, a kind of island detection method provided by the invention has the characteristics that detectability is strong, current distortion is small, is applicable in
In more photovoltaic systems.
4, a kind of island detection method provided by the invention, testing cost is low, has the market competitiveness.
5, a kind of island detection method provided by the invention, can accurately and effectively detect electric network power-fail, cut off rapidly
The connection of inverter and power grid.
Detailed description of the invention
Fig. 1 is the working principle diagram of power circuit of the present invention；
Fig. 2 is the working principle diagram of pre-driver circuitry of the present invention；
Fig. 3 is the working principle diagram of post-stage drive circuit of the present invention；
Fig. 4 is the working principle diagram of prime push-pull circuit of the present invention；
Fig. 5 is the working principle diagram of current rectifying and wave filtering circuit of the present invention；
Fig. 6 is the working principle diagram of rear class inverter circuit of the present invention；
Fig. 7 is the working principle diagram of current sampling circuit of the present invention；
Fig. 8 is the working principle diagram of voltage sampling circuit of the present invention；
Fig. 9 is the working principle diagram of line voltage sample circuit of the present invention；
Figure 10 is the working principle diagram of comparison circuit of the invention；
Figure 11 is the working principle diagram of control module of the present invention；
Figure 12 is the circuit fundamental diagram of alone island detection system of the present invention；
Figure 13 is the schematic diagram of phase difference of the present invention；
Figure 14 is the voltage value variation diagram that the present invention is added after phase perturbation；
Figure 15 is the structural schematic diagram of alone island detection system of the present invention.
Specific embodiment
Present invention will be described in further detail below with reference to the accompanying drawings, to enable those skilled in the art referring to specification text
Word can be implemented accordingly.
In the present specification, when an element is mentioned as " be connected to or be coupled to " another element or " is arranged another
In one element " when, can " direct " be connected to or be coupled to another element or it is " direct " be arranged in another element.Or with
The intervenient mode of other elements is connected to or is coupled to another element or is arranged in another element, unless it is by volume
" be coupled directly to or be connected to " another element or " directly setting " are in another element.Furthermore, it is to be understood that when an element quilt
It, can when referring to as " on another element ", " above another element ", " under another element " or " below another element "
It contacts with another element " direct " or is contacted in a manner of having intervened other elements therebetween with another element, unless it is mentioned as
It is directly contacted with another element.
As shown in figure 15, a kind of alone island detection system characterized by comprising
Control module；
Inverter circuit is connect with the control module, for generating SPWM waveform；
Output signal circuit, one end are connect with the inverter circuit, the other end of the output signal circuit with it is described
Control module connection, for exporting network wave；
Comparison circuit is connect with the output signal circuit and the control module, is used to the SPWM waveform
The zero point moment and the network wave the zero point moment between time difference, if positively biased, define the zero point moment it
Between time difference be the zero point moment SPWM pointer value, if reverse-biased, defining time difference between the zero point moment is one
The number of total SPWM wave in a period subtracts the pointer value of SPWM；
Wherein, the control module detects the SPWM pointer value at the zero point moment or the total SPWM wave for a cycle
Whether the pointer value that number subtracts SPWM fluctuates in fixed range.
The SPWM pointer value at zero point moment is monitored, normally in grid-connected situation, the SPWM pointer value of zero point can be in a very little
In the range of fluctuate, if SPWM pointer value be a changeless value or pointer value jump it is very big, all illustrate power grid electricity
Reduce off-flavor is normal, and the inverter circuit closes output, effectively achieves isolated island detection.
On the basis of above situation, another embodiment, the inverter circuit includes prime push-pull circuit, rectifying and wave-filtering
Circuit, rear class inverter circuit and LCL filter circuit, output end and the current rectifying and wave filtering circuit of the prime push-pull circuit
Input terminal connection, the output end of the current rectifying and wave filtering circuit are connect with the input terminal of the rear class inverter circuit, and the rear class is inverse
The output end on power transformation road is connect with the input terminal of the LCL filter circuit.
The prime push-pull circuit is prime transformer, as shown in figure 4, the primary 24V of transformer inputs (this inverter mark
Title is 24V, and the meaning in the art is exactly to actually enter voltage range to work normally within 20-30V), it is secondary
(minimum after prime boosting must be 340 or more voltages, and rear class inversion could export 220V voltage, so selection 380 for 380V output
It is to stay certain surplus), C2, C, C4 selects high-frequency electrolysis capacitor, and (C2, C3, C4 are mainly filter action, High frequency filter effect
Good, series equivalent resistance (ESR) is small, so capacitor calorific value is small, delivery efficiency can be improved), PWM_BOUT in attached drawing 4,
PWM_AOUT is the output signal of MIC4452, for driving the MOS in prime push-pull circuit, and by push-pull transformer come real
Existing prime boosting；Using the pwm signal of the PWM1 and PWM2 of control module the two-way phase phase difference 180 generated, pushed away for prime
Boosting is drawn, two-way phase difference cannot be too big, and too big to generate bias, prime MOS can be burnt out.
The secondary output of the push-pull transformer of the prime push-pull circuit passes through the current rectifying and wave filtering circuit, as shown in figure 5,
Output DC380V voltage (minimum after prime boosting must be 340 or more voltages, and rear class inversion could export 220V voltage, so
Selection 380 is to stay certain surplus), and it is output to rear class inverter circuit.
As shown in fig. 6, rear class inverter circuit is given in direct current 380V after filtering arrangement, output, the rear class inverter circuit passes through
Control module exports SPWM signal, PWM1H, PWM1L, PWM2H, PWM2L, and passes through post-stage drive circuit, output drive signal
HO1, LO1, HO2, LO2 control 4 MOS of full-bridge in rear class inverter circuit, realize full-bridge inverting.
After filtering again by LCL after the voltage signal of full-bridge inverting output, the sine wave of standard 50HZ is outputed.
On the basis of the above embodiments, further embodiment further includes pre-driver circuitry and post-stage drive circuit, institute
The one end for stating pre-driver circuitry and the post-stage drive circuit is connect with the control module, the pre-driver circuitry
The other end is connect with the other end of the prime push-pull circuit, the other end of the post-stage drive circuit and rear class inversion electricity
The input terminal on road connects.
MIC4452 driving chip is used in the pre-driver circuitry, MIC4452 is that a peak value drives up to 12A
Low pressure MOS driving, is powered, as shown in Fig. 2 circuit diagram, PWM_A, PWM_B are PWM1, PWM2 of control module using 12V
Output signal, PWM_BOUT, PWM_AOUT are the output signals of MIC4452, for driving the MOS in prime push-pull circuit, and
Realize that prime is boosted by push-pull transformer.The input of MIC4452 must connect the pull down resistor of 10K, when not so powering on, be easy
There is PWM_AOUT, PWM_BOUT with high situation, can thus burn out prime MOS.
The post-stage drive circuit exports SPWM signal, PWM1H, PWM1L, PWM2H, PWM2L by control module, and leads to
Overdrive IR2110, and output drive signal HO1, LO1, HO2, LO2 control rear class inverter circuit.The IR2110 is U.S. IR public affairs
Take charge of the high-pressure MOS driver of production.It has the advantages of light-coupled isolation (small in size) and electromagnetic isolation (speed is fast) concurrently.
On the basis of the above embodiments, further embodiment, the output signal circuit include current sampling circuit, electricity
Press sample circuit and line voltage sample circuit, the current sampling circuit, the voltage sampling circuit and the network voltage
One end of sample circuit is connect with the output end of the LCL filter circuit, the current sampling circuit, voltage sample electricity
Road is connect with the control module with the other end of the line voltage sample circuit；
Wherein, one end of the line voltage sample circuit is connect with the comparison circuit.
The working principle diagram of current sampling circuit as shown in Figure 7 uses HCS_LSP15 current sensor, HCS_
LSP15 is serially connected in output loop, and HCS_LSP15 output is the signal using 2.5V as midpoint.Single-chip microcontroller can be sampled directly.It is described
The input terminal of current sampling circuit is connect with the output end of the LCL filter circuit, the output end of the current sampling circuit with
The connection of the control module.
The working principle diagram of voltage sampling circuit as shown in Figure 8, the input terminal of the voltage sampling circuit and the LCL
The output end of filter circuit connects, and the output end of the voltage sampling circuit is connect with the control module, the bus electricity of circuit
Pressure is that 380V is adopted so being exported using the electric resistance partial pressure of three 1M, then by amplifier to control module for the control module
Sample.
The working principle diagram of line voltage sample circuit as shown in Figure 9, the power grid in the line voltage sample circuit
Voltage is by mutual inductor, evanescent voltage amplitude, then after filtering by amplifier, control module is directly output to all the way, for control mould
Block sampling, then exports to the anode of the comparison circuit all the way, compares for comparator, wherein network voltage detection mutual inductor
Mode sample effect be better than the mode to be decayed with amplifier, 220V voltage passes through primary current limliting decaying, and secondary series resistor R92 is adopted
220 voltage signal of sample, on R92 and C49 is met, the HF switch interference burr that can largely decay in sampled signal,
C59 is concatenated, the effect every value filtering is primarily served.
Above-mentioned output signal circuit can guarantee that the signal sampled is really, and effective signal could correctly be sentenced in this way
Disconnected dead-center position, is just able to achieve grid-connected, guarantees that inverter operates normally, just can guarantee accurate detection phase deviation.
On the basis of the above embodiments, further embodiment, the comparison circuit include comparator, anode with it is described
Line voltage sample circuit connection, the negative terminal of the comparator connect 2.5V reference voltage, the output end of the comparator with it is described
Control module connection.
As shown in Figure 9 and Figure 10, the line voltage sample circuit exports all the way to the comparison in the comparison circuit
The anode of device, the negative terminal of the comparator connect 2.5V reference voltage, detect zero crossing, the output connection control mould of the comparator
Block.
Voltage sampling signal in the line voltage sample circuit is by amplifier filter circuit, so that it becomes being with 2.5V
The sinusoidal signal at midpoint, this signal are input to the anode of comparator, are compared with the negative terminal 2.5V reference voltage of comparator, from
And detect zero crossing, and be input to the I/O port of single-chip microcontroller, for monolithic machine testing.In order to improve the anti-interference of single-chip microcontroller IO detection
Ability, herein using AD inquiry mode come the output state of detection comparator.The every 50US of single-chip microcontroller is compared by AD sampling judgement
The voltage value of the delivery outlet of device, sampling three times, if sampled result is both greater than 3V three times, illustrates the high electricity of comparator output every time
It is flat, if result is both less than 1V three times, illustrate that comparator exports low level.
Low and high level is two states, and level can be set and be lower by height as zero point triggering moment, also can be set by low
It gets higher as zero point phase triggering moment, specifically selects any, determined by hardware circuit.
On the basis of the above embodiments, further embodiment, the control module are the MCU of HYM8F028C6 model.
As shown in figure 11, the MCU of this system is selected as HYM8F028C6, has the advantage that clock frequency 60MHz；
256 byte inner RAM, 3072 byte external RAMs, 2048 bytes (totally 16 sectors, the byte of each sector 128) EEPROM；
Multiplication and division function, no symbol 16x 16-bit, symbol 16x 16-bit, no symbol 32/16；It is internally integrated 2 road transports to put, passes through outside
Configuration, programmable gain amplifier are compatible with single-ended input pattern and two kinds of Differential Input mode；1 road comparator, comparator output
Signal can stop MPWM work while make MPWM output port high-impedance state；Comparator, which exports rising edge, can trigger ADC；Input
Negative terminal can connect external input voltage, inside DAC output as reference voltage；Input anode can connect external input voltage, may be programmed
Gain amplifier output end；12 AD, may be implemented while two-way samples, any time trigger that can also be exported in PWM
AD conversion；3 16, tunnel complementary output PWM, dead time can be set, and alignment pattern can be set, and have brake function；So using
The 2 tunnel complementation PWM of HYM8F028C6 are improved to develop and be imitated to realize that rear class SPWM inversion greatly reduces written in code difficulty
Rate.
The pwm signal that two-way phase phase difference 180 is generated using the PWM1 and PWM2 of MCU, recommends boosting, two-way for prime
Phase difference cannot be too big, and too big to generate bias, prime MOS can be burnt out.
On the basis of the above embodiments, further embodiment further includes power supply, all the way with the pre-driver circuitry
Connection, the another way of the power supply are connect with the control module；
As shown in Figure 1,24V inputs LM2576, the voltage for supplying the pre-driver circuitry all the way of LM2576 output end
L7805 is resupplied for 12V, 12V, 5V is generated and powers to MCU.
Voltage gradually turns low-voltage by high voltage in this way, and such efficiency can be better.
Wherein about the generation of SPWM, it is first determined the frequency of SPWM, such as 40K will export the sine wave of 50HZ, X/
40K=50HZ calculates the value of X, the i.e. points of a cycle.After points determine, EXCEL or related software can be used, is generated sinusoidal
Table, single-chip microcontroller are driven the full-bridge MOS of rear class inverter circuit, upper tube PWM can be used by the value in the rate-adaptive pacemaker sine table of 40K,
Down tube switching mode, upper and lower bridge work alternatively, that is, produce SPWM waveform.
In alone island detection system provided by the invention, after single-chip microcontroller captures the over-current signal of comparator, remember this moment
SPWM pointer value differs greatly compared with the value of practical zero point, surveys the value by the way that SPWM pointer is decreased or increased, phase difference is made to contract
It is small, that is, reach a phase-locked function.
It after grid-connected under normal circumstances, is controlled by locking phase, the phase and inversion electricity of line voltage sample circuit output
The phase of road output is remembered substantially without phase difference, single-chip microcontroller by capturing the output signal of zero-acrross ing moment comparator
SPWM pointer value at this time, ideally, SPWM pointer value adds 1 or subtracts 1 at this time, it is made to be attributed to 0, to reach the mesh of locking phase
, but since due to inductance in phase detecting circuit, the presence of capacitor, the value of the practical SPWM pointer in zero-acrross ing moment is not necessarily
It is 0, for example 200 points of a cycle, the value of zero-acrross ing moment SPWM pointer are likely to be 20, it is also possible to 195, with specific reference to reality
Border circuit, is debugged with oscillograph.
After locking phase, after success is grid-connected, phase perturbation is added, i.e., by adjusting single-chip microcontroller in zero-acrross ing moment SPWM pointer
When the zero point of the network wave of value, the zero point moment for the waveform for exporting rear class inverter circuit and line voltage sample circuit output
It is poor to be carved with the regular hour, in this way, as shown in figure 13.
Voltage when the general voltage that the phase perturbation moment is added can be lower than without phase difference, as shown in figure 14, so, add
Applying aspect disturbs function, and detects voltage value simultaneously, if voltage in allowable fluctuation range, illustrates that network operation is normal, such as
Phase perturbation is added in fruit, and voltage does not fluctuate, then illustrates power grid exception, the connection of inverter and power grid is cut off immediately, to reach
The purpose detected to isolated island.
Alternatively, the SPWM pointer at monitoring zero point moment, normally in grid-connected situation, the SPWM pointer of zero point can be in a very little
In the range of fluctuate, if SPWM pointer be a changeless value or pointer value jump it is very big, all illustrate network voltage
Abnormal, inverter closes output.Using above two method, it can effectively reach isolated island detection.
The present invention to change the output phase of rear class inverter circuit, then is passed through by the SPWM pointer value of change zero point
The variation of monolithic machine testing output voltage amplitude, thus judge alternating current whether normal operation.
The present invention provides a kind of island detection method on the basis of above-mentioned hardware system, which is characterized in that including
Following steps:
S101 generates SPWM waveform and network wave respectively by inverter circuit and output signal circuit；
S102 comes the zero point moment of SPWM waveform described in comparison and the zero point moment of the network wave by comparing circuit
Between time difference then define the SPWM that time difference between the zero point moment is the zero point moment when time difference positively biased and refer to
Needle value；When the time difference is reverse-biased, then the number for being defined as total SPWM wave of a cycle subtracts the pointer value of SPWM；
Whether the SPWM pointer value that S103 control module detects the comparison circuit output fluctuates in fixed range.
The SPWM pointer value at zero point moment is monitored, normally in grid-connected situation, the SPWM pointer value of zero point can be in a very little
In the range of fluctuate, such as an alternating current is 50HZ, i.e. 20mS, and a cycle is made of 400 SPWM points, locking phase control one
As can control in the range of differing 5 points.
If SPWM pointer value is a changeless value (as long as judgement is not fluctuated, so that it may judge power grid exception
) or the value jump of pointer it is very big, all illustrate network voltage exception, the inverter circuit closes output, effectively achieves isolated island
Detection.
In step S01, the inverter circuit include prime push-pull circuit, current rectifying and wave filtering circuit, rear class inverter circuit and
The output end of LCL filter circuit, the prime push-pull circuit is connect with the input terminal of the current rectifying and wave filtering circuit, the rectification
The output end of filter circuit is connect with the input terminal of the rear class inverter circuit, the output end of the rear class inverter circuit with it is described
The input terminal of LCL filter circuit connects；
The prime push-pull circuit is prime transformer, as shown in figure 4, the primary 24V of transformer inputs (this inverter mark
Title is 24V, and the meaning of 24V input is exactly to actually enter voltage range within 20-30V in the art), secondary 380V output
(minimum after prime boosting must be 340 or more voltages, and rear class inversion could export 220V voltage, so selection 380 is to stay centainly
Surplus), C2, C, C4 select high-frequency electrolysis capacitor (C2, C3, C4 are mainly filter action, and High frequency filter effect is good, series connection etc.
Imitate resistance (ESR) it is small, so capacitor calorific value is small, delivery efficiency can be improved), PWM_BOUT, PWM_AOUT in attached drawing 4 are
The output signal of MIC4452 for driving the MOS in prime push-pull circuit, and realizes that prime is boosted by push-pull transformer；
Using the pwm signal of the PWM1 and PWM2 of control module the two-way phase phase difference 180 generated, boosting, two-way are recommended for prime
Phase difference cannot be too big, and too big to generate bias, prime MOS can be burnt out.
The secondary output of the push-pull transformer of the prime push-pull circuit passes through the current rectifying and wave filtering circuit, as shown in figure 5,
DC380V voltage is exported, and is output to rear class inverter circuit.
As shown in fig. 6, rear class inverter circuit is given in direct current 380V after filtering arrangement, output, the rear class inverter circuit passes through
Control module exports SPWM signal, PWM1H, PWM1L, PWM2H, PWM2L, and passes through post-stage drive circuit, output drive signal
HO1, LO1, HO2, LO2 control 4 MOS of full-bridge in rear class inverter circuit, realize full-bridge inverting.
After filtering again by LCL after the voltage signal of full-bridge inverting output, the sine wave of standard 50HZ is outputed.
It wherein, further include pre-driver circuitry and post-stage drive circuit, the pre-driver circuitry and the rear class drive
One end of circuit is connect with the control module, and the other end of the pre-driver circuitry is another with the prime push-pull circuit
One end connection, the other end of the post-stage drive circuit are connect with the input terminal of the rear class inverter circuit.
MIC4452 driving chip is used in the pre-driver circuitry, MIC4452 is that a peak value drives up to 12A
Low pressure MOS driving, is powered, as shown in Fig. 2 circuit diagram, PWM_A, PWM_B are PWM1, PWM2 of control module using 12V
Output signal, PWM_BOUT, PWM_AOUT are the output signals of MIC4452, for driving the MOS in prime push-pull circuit, and
Realize that prime is boosted by push-pull transformer.The input of MIC4452 must connect the pull down resistor of 10K, when not so powering on, be easy
There is PWM_AOUT, PWM_BOUT with high situation, can thus burn out prime MOS.
The post-stage drive circuit exports SPWM signal, PWM1H, PWM1L, PWM2H, PWM2L by control module, and leads to
Overdrive IR2110, and output drive signal HO1, LO1, HO2, LO2 control rear class inverter circuit.The IR2110 is U.S. IR public affairs
Take charge of the high-pressure MOS driver of production.It has the advantages of light-coupled isolation (small in size) and electromagnetic isolation (speed is fast) concurrently.
In S101 step, the output signal circuit includes current sampling circuit, voltage sampling circuit and network voltage
Sample circuit, the current sampling circuit, the voltage sampling circuit and the line voltage sample circuit one end and institute
The output end connection of LCL filter circuit is stated, the current sampling circuit, the voltage sampling circuit and the network voltage sample
The other end of circuit is connect with the control module；
Wherein, one end of the line voltage sample circuit is connect with the comparison circuit.
The working principle diagram of current sampling circuit as shown in Figure 7 uses HCS_LSP15 current sensor, HCS_
LSP15 is serially connected in output loop, and HCS_LSP15 output is the signal using 2.5V as midpoint.Single-chip microcontroller can be sampled directly.It is described
The input terminal of current sampling circuit is connect with the output end of the LCL filter circuit, the output end of the current sampling circuit with
The connection of the control module.
The working principle diagram of voltage sampling circuit as shown in Figure 8, the input terminal of the voltage sampling circuit and the LCL
The output end of filter circuit connects, and the output end of the voltage sampling circuit is connect with the control module, the bus electricity of circuit
Pressure is that 380V is adopted so being exported using the electric resistance partial pressure of three 1M, then by amplifier to control module for the control module
Sample.
The working principle diagram of line voltage sample circuit as shown in Figure 9, the power grid in the line voltage sample circuit
Voltage is by mutual inductor, evanescent voltage amplitude, then after filtering by amplifier, control module is directly output to all the way, for control mould
Block sampling, then exports to the anode of the comparison circuit all the way, compares for comparator, wherein network voltage detection mutual inductor
Mode sample effect be better than the mode to be decayed with amplifier, 220V voltage passes through primary current limliting decaying, and secondary series resistor R92 is adopted
220 voltage signal of sample, on R92 and C49 is met, the HF switch interference burr that can largely decay in sampled signal,
C59 is concatenated, the effect every value filtering is primarily served.
In S102 step, the comparison circuit includes comparator, and anode is connect with the line voltage sample circuit,
The negative terminal of the comparator connects 2.5V reference voltage, and the output end of the comparator is connect with the control module.
As shown in Figure 9 and Figure 10, the line voltage sample circuit exports all the way to the comparison in the comparison circuit
The anode of device, the negative terminal of the comparator connect 2.5V reference voltage, detect zero crossing, the output connection control mould of the comparator
Block.
Voltage sampling signal in the line voltage sample circuit is by amplifier filter circuit, so that it becomes being with 2.5V
The sinusoidal signal at midpoint, this signal are input to the anode of comparator, are compared with the negative terminal 2.5V reference voltage of comparator, from
And detect zero crossing, and be input to the I/O port of single-chip microcontroller, for monolithic machine testing.In order to improve the anti-interference of single-chip microcontroller IO detection
Ability, herein using AD inquiry mode come the output state of detection comparator.The every 50US of single-chip microcontroller is compared by AD sampling judgement
The voltage value of the delivery outlet of device, sampling three times, if sampled result is both greater than 3V three times, illustrates the high electricity of comparator output every time
It is flat, if result is both less than 1V three times, illustrate that comparator exports low level.
In S103 step, the control module is connect with the inverter circuit, one end of the output signal circuit with
The inverter circuit connection, the other end of the output signal circuit are connect with the control module, the comparison circuit and institute
Output signal circuit is stated to connect with the control module；Wherein, the control module is the MCU of HYM8F028C6 model.
As shown in figure 11, the MCU of this system is selected as HYM8F028C6, has the advantage that clock frequency 60MHz；
256 byte inner RAM, 3072 byte external RAMs, 2048 bytes (totally 16 sectors, the byte of each sector 128) EEPROM；
Multiplication and division function, no symbol 16x 16-bit, symbol 16x 16-bit, no symbol 32/16；It is internally integrated 2 road transports to put, passes through outside
Configuration, programmable gain amplifier are compatible with single-ended input pattern and two kinds of Differential Input mode；1 road comparator, comparator output
Signal can stop MPWM work while make MPWM output port high-impedance state；Comparator, which exports rising edge, can trigger ADC；Input
Negative terminal can connect external input voltage, inside DAC output as reference voltage；Input anode can connect external input voltage, may be programmed
Gain amplifier output end；12 AD, may be implemented while two-way samples, any time trigger that can also be exported in PWM
AD conversion；3 16, tunnel complementary output PWM, dead time can be set, and alignment pattern can be set, and have brake function；So using
The 2 tunnel complementation PWM of HYM8F028C6 are improved to develop and be imitated to realize that rear class SPWM inversion greatly reduces written in code difficulty
Rate.
The pwm signal that two-way phase phase difference 180 is generated using the PWM1 and PWM2 of MCU, recommends boosting, two-way for prime
Phase difference cannot be too big, and too big to generate bias, prime MOS can be burnt out.
Wherein, further include power supply, connect all the way with the pre-driver circuitry, the another way of the power supply and the control
The connection of molding block；
As shown in Figure 1,24V inputs LM2576, the voltage for supplying the pre-driver circuitry all the way of LM2576 output end
L7805 is resupplied for 12V, 12V, 5V is generated and powers to MCU.
Voltage gradually turns low-voltage by high voltage in this way, and such efficiency can be better.
Wherein, about the generation of SPWM, it is first determined the frequency of SPWM, such as 40K will export the sine wave of 50HZ, X/
40K=50HZ calculates the value of X, the i.e. points of a cycle.After points determine, EXCEL or related software can be used, is generated sinusoidal
Table, single-chip microcontroller are driven the full-bridge MOS of rear class inverter circuit, upper tube PWM can be used by the value in the rate-adaptive pacemaker sine table of 40K,
Down tube switching mode, upper and lower bridge work alternatively, that is, produce SPWM waveform.
On the basis of the above embodiments, another embodiment, it is described to carry out SPWM waveform described in comparison by comparing circuit
The zero point moment and the network wave the zero point moment between time difference, and define the time difference between zero point moment
For the zero point moment SPWM pointer value or be a cycle total SPWM wave number subtract SPWM pointer value before further include:
After control module described in S201 step captures the zero cross signal of the comparison circuit, SPWM pointer this moment is remembered
Value, compared with the SPWM pointer value at zero point moment after, differ greatly, then by being decreased or increased SPWM pointer value, reduce phase difference,
Reach a phase-locked function, even if be carved with certain when the zero point of the zero point moment of the SPWM waveform and the network wave
Between it is poor.
It after grid-connected under normal circumstances, is controlled by locking phase, the phase and inversion electricity of line voltage sample circuit output
The phase of road output is remembered substantially without phase difference, single-chip microcontroller by capturing the output signal of zero-acrross ing moment comparator
SPWM pointer value at this time, ideally, SPWM pointer value adds 1 or subtracts 1 at this time, it is made to be attributed to 0, to reach the mesh of locking phase
, but since due to inductance in phase detecting circuit, the presence of capacitor, the value of the practical SPWM pointer in zero-acrross ing moment is not necessarily
It is 0, for example 200 points of a cycle, the value of zero-acrross ing moment SPWM pointer are likely to be 20, it is also possible to 195, with specific reference to reality
Border circuit, is debugged with oscillograph.
After locking phase, after success is grid-connected, phase perturbation is added, i.e., by adjusting single-chip microcontroller in zero-acrross ing moment SPWM pointer
When the zero point of the network wave of value, the zero point moment for the waveform for exporting rear class inverter circuit and line voltage sample circuit output
It is poor to be carved with the regular hour, in this way, as shown in figure 13.
Voltage when the general voltage that the phase perturbation moment is added can be lower than without phase difference, as shown in figure 14, so, add
Applying aspect disturbs function, and detects voltage value simultaneously, if voltage in allowable fluctuation range, illustrates that network operation is normal, such as
Phase perturbation is added in fruit, and voltage does not fluctuate, then illustrates power grid exception, the connection of inverter and power grid is cut off immediately, to reach
The purpose detected to isolated island.
Alternatively, the SPWM pointer at monitoring zero point moment, normally in grid-connected situation, the SPWM pointer of zero point can be in a very little
In the range of fluctuate, if SPWM pointer be a changeless value or pointer value jump it is very big, all illustrate network voltage
Abnormal, inverter closes output.Using above two method, it can effectively reach isolated island detection.
The present invention to change the output phase of rear class inverter circuit, then is passed through by the SPWM pointer value of change zero point
The variation of monolithic machine testing output voltage amplitude, thus judge alternating current whether normal operation.
Switch mosfet used in the present invention is a kind of field effect that can be widely used in analog circuit and digital circuit
Transistor, major advantage: thermal stability is good, safety operation area is big, and in conducting with extremely low internal resistance, switching speed is fast,
Improve the efficiency of power amplifier.
It is readily apparent that those skilled in the art can obtain from the various structures of embodiment according to the present invention
Obtain the various effects not yet referred directly to according to unpainful each embodiment.
Although the embodiments of the present invention have been disclosed as above, but its is not only in the description and the implementation listed
With.It can be applied to various suitable the field of the invention completely.It for those skilled in the art, can be easily
Realize other modification.Therefore without departing from the general concept defined in the claims and the equivalent scope, the present invention is simultaneously unlimited
In specific details and legend shown and described herein.
Claims (10)
1. a kind of alone island detection system characterized by comprising
Control module；
Inverter circuit is connect with the control module, for generating SPWM waveform；
Output signal circuit, one end are connect with the inverter circuit, the other end of the output signal circuit and the control
Module connection, for exporting network wave；
Comparison circuit is connect with the output signal circuit and the control module, for the zero of the SPWM waveform
Time difference between point moment and the zero point moment of the network wave, and the time difference defined between the zero point moment is zero
The SPWM pointer value of point moment；
Wherein, whether the SPWM pointer value that the control module detects the zero point moment fluctuates in fixed range.
2. alone island detection system as described in claim 1, which is characterized in that the inverter circuit include prime push-pull circuit,
Current rectifying and wave filtering circuit, rear class inverter circuit and LCL filter circuit, the output end of the prime push-pull circuit and the rectification are filtered
The input terminal of wave circuit connects, and the output end of the current rectifying and wave filtering circuit is connect with the input terminal of the rear class inverter circuit, institute
The output end for stating rear class inverter circuit is connect with the input terminal of the LCL filter circuit.
3. alone island detection system as claimed in claim 2, which is characterized in that further include pre-driver circuitry and rear class driving electricity
One end of road, the pre-driver circuitry and the post-stage drive circuit is connect with the control module, the prime driving
The other end of circuit is connect with the other end of the prime push-pull circuit, the other end of the post-stage drive circuit and the rear class
The input terminal of inverter circuit connects.
4. alone island detection system as claimed in claim 2, which is characterized in that the output signal circuit includes current sample electricity
Road, voltage sampling circuit and line voltage sample circuit, the current sampling circuit, the voltage sampling circuit and the power grid
One end of voltage sampling circuit is connect with the output end of the LCL filter circuit, and the current sampling circuit, the voltage are adopted
Sample circuit is connect with the control module with the other end of the line voltage sample circuit；
Wherein, one end of the line voltage sample circuit is connect with the comparison circuit.
5. alone island detection system as claimed in claim 4, which is characterized in that the comparison circuit includes comparator, anode
It is connect with the line voltage sample circuit, the negative terminal of the comparator connects 2.5V reference voltage, the output end of the comparator
It is connect with the control module.
6. alone island detection system as described in claim 1, which is characterized in that the control module is HYM8F028C6 model
MCU。
7. alone island detection system as claimed in claim 3, which is characterized in that further include power supply, driven all the way with the prime
Dynamic circuit connection, the another way of the power supply are connect with the control module；
Wherein, the input voltage of power supply is 24V, and the voltage all the way of pre-driver circuitry described in the power supply is 12V, institute
The voltage all the way for stating control module described in power supply is 5V.
8. a kind of island detection method, which comprises the following steps:
By inverter circuit and output signal circuit, SPWM waveform and network wave are generated respectively；
Come by comparing circuit between the zero point moment of SPWM waveform described in comparison and the zero point moment of the network wave when
Between it is poor, define the SPWM pointer value that time difference between the zero point moment is the zero point moment；
Whether the SPWM pointer value that control module detects the comparison circuit output fluctuates in fixed range.
9. island detection method as claimed in claim 8, which is characterized in that described to carry out SPWM described in comparison by comparing circuit
Time difference between the zero point moment of waveform and the zero point moment of the network wave, and define between zero point moment when
Between difference be the zero point moment SPWM pointer value before further include:
After the control module captures the zero cross signal of the comparison circuit, SPWM pointer value this moment is remembered, when with zero point
The SPWM pointer value at quarter relatively after, differ greatly, then by being decreased or increased SPWM pointer value, phase difference reduced, even if described
It is poor that the regular hour is carved with when the zero point of zero point moment of SPWM waveform and the network wave.
10. island detection method as claimed in claim 8, which is characterized in that the inverter circuit include prime push-pull circuit,
Current rectifying and wave filtering circuit, rear class inverter circuit and LCL filter circuit, the output end of the prime push-pull circuit and the rectification are filtered
The input terminal of wave circuit connects, and the output end of the current rectifying and wave filtering circuit is connect with the input terminal of the rear class inverter circuit, institute
The output end for stating rear class inverter circuit is connect with the input terminal of the LCL filter circuit；
The output signal circuit includes line voltage sample circuit, the input terminal of the line voltage sample circuit with it is described
The output end of LCL filter circuit connects, and an output end of the line voltage sample circuit is connect with the control module, institute
The another output for stating line voltage sample circuit is connect with the comparison circuit；
The comparison circuit includes comparator, and anode is connect with the line voltage sample circuit, the negative terminal of the comparator
2.5V reference voltage is connect, the output end of the comparator is connect with the control module.
Wherein, the control module is the MCU of HYM8F028C6 model.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910658747.9A CN110456214B (en) | 2019-07-22 | Island detection system and island detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910658747.9A CN110456214B (en) | 2019-07-22 | Island detection system and island detection method |
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| CN110456214B CN110456214B (en) | 2024-07-05 |
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| CN101257209A (en) * | 2008-01-10 | 2008-09-03 | 清华大学深圳研究生院 | Islet operation detecting method of photovoltaic parallel network generating system |
| CN102393482A (en) * | 2011-10-11 | 2012-03-28 | 深圳市京泉华电子有限公司 | Grid-connected inverter and circuit for detecting island thereof |
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