TW201015822A - Power-converting device with islanding detection and control method thereof - Google Patents

Abstract

A power-converting device with islanding detection and a control method thereof is provided. The power-converting device comprises a power converter, and a control circuit controlling a plurality of power switches of the power converter, with the power converter connecting to an AC power source and a load through a link inductor. The control method for the proposed power-converting device comprises detecting a voltage of the load and sending a result to a power control unit and a phase shift unit, generating a power control signal and a phase shift signal by the two units respectively, adding said two signals by an adder, transferring the result of the adder to a PWM circuit to obtain a set of PWM signals, and finally transferring the PWM signals to a driver circuit, so as to generate driving signals for driving the power switches of the power converter.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power conversion apparatus for a distributed power supply system, and more particularly to a power conversion apparatus with islanding operation detection and a control method therefor. [Prior Art] Since the greenhouse gas emissions of countries around the world are limited by the Kyoto Protocol, and the cost of petrochemical energy is becoming more and more expensive, the cost of renewable energy is reduced, resulting in low pollution and low greenhouse gas emissions. The renewable energy power generation technology has gradually received worldwide attention. Among them, renewable energy generation technologies such as wind energy, solar energy and fuel cells, which are more promising and forward-looking, have attracted more attention. As usual. 'Regeneration of this source power generation system or small power generation system can constitute a small decentralized power supply system, which can be integrated into the general AC power distribution system to supply the generated power to the load connected to the AC power distribution system . Among them, the main key technology of the small distributed power system and the AC power distribution system in parallel is the power converter interface technology, and the conventional power converter interface technology can be divided into current control type and electric type according to the control method type, and Most of the conventional power converters are current controlled. $And 'Using current-controlled power conversion|^ used in the disaster-proof power generation system' In addition to the inherent one-current control loop, an additional 2 voltage control loops must be added to control the wheel of the current-controlled power converter ^Pressure; In addition, the conventional voltage-controlled power converter must use the two-loop control of the amplitude and phase of the power conversion H output power I. 201015822 'There is obvious control circuit complexity, and because of the dual-loop control This leads to shortcomings such as poor transient response characteristics. On the other hand, when the small distributed power system is directly connected in parallel to the AC power distribution system to supply power to the load, the entire power transmission and distribution system needs to be provided with appropriate protection measures, including power quality detection and island operation. The so-called island operation means that when the AC power distribution system is disconnected from the small distributed power system due to failure or maintenance, if the small distributed power system continues to supply power, Part of the transmission and distribution system still connected to the small distributed power system presents a phenomenon of isolated island operation with separate power. This islanding phenomenon will cause the following problems: 1. Hazard to the maintenance personnel in the operation area of the island; 2. The voltage and frequency of the island operation area are unstable, thus damaging the electrical equipment or load located in the island operation area; The protection power in the operation area of the island is malfunctioning. 4. When the AC power distribution system resumes power supply, the problem that the small 0 distributed power system is not synchronized with the AC power distribution system may occur. In view of this, in the international research institutions in Europe, the United States, Japan and other countries have developed regulatory standards, such as IEEE929, IEEE1547, VDE0126-1-1 and UL1741. In view of the above situation, the detection methods of the island operation mainly include the passive detection method and the active detection method. Among them, passive detection methods such as system frequency detection method, voltage amplitude detection method and harmonic content detection method, etc., use the detection system parameter changes to determine whether islanding phenomenon occurs. However, these passive detection methods have a feeling of not feeling, and 201015822

In the non-sensing zone, these passive detection methods are unable to produce the condition of the operation of the lone j. Therefore, the _ side branch does not find the full satisfaction of the above-mentioned tube: regulation standard. As for the silk type nucleation, it is added to the distributed power source to add a small amount of small disturbance. When the delivery system is operating normally, the small amount of disturbance will not cause any impact due to its ugly power supply; on the contrary, once the communication gn and the operation of the system are interrupted, the small amount can cause fresh or voltage. A change in amplitude, so it can be deceived by the protection of electricity and the phenomenon of islanding. At this point, the decentralized power system can be immediately disconnected from the rest of the drive and the other parts of the drive to avoid island operations. 〇About the active side method of the prior art, U.S. Patent No. 5,493,485 discloses the use of a decentralized power supply system to generate an output current having phase shift and spectral distortion. The simplified distributed power supply is a phenomenon of islanding operation; Patent No. 6,172,889 discloses the use of a decentralized power system to generate an output current with a frequency offset, and then the positive feedback mode side of the distributed power supply is a phenomenon of operation of the island; the Republic of China Patent Notice No. 430731 Revealing the decentralized power supply system, Chengsheng-asymmetric wheel current, H-distributed money, whether or not island operation occurs; US Patent No. 6,603,290 discloses that a certain amount of harmonics is input to a decentralized power system _, and then measured The decentralized power supply has pure impedance to detect whether the distributed power system has an islanding phenomenon; and another conventional active detection method is disclosed in IET Renewable p〇wer

Generation Vol. 1, No. 3, pp.175-181, September 2007] will not disclose a current-controlled power converter at a frequency close to and not equal to one to one 8:201015822 Money, to the side of the distributed power system whether islanding phenomenon occurs.

As described above, these active methods of measurement use the power converter of the distributed power system to generate small distortions in order to facilitate the operation of the distributed power system in the AC power distribution system. However, these main-side methods must be limited. The total spectral distortion rate of this distributed m-shaped supply current must be less than 5%. In short, the amount of distortion generated by these active side methods must be limited, and this will affect the time and reliability of detecting the operation of the island. Therefore, the above-mentioned conventional island operation detection method not only needs to use a more complicated control circuit, but may even have a presence-and-no sense belt. These active type methods all use current-controlled power conversion n, and if (4) residual system The f-force converter operates as an anti-inflammatory power-storage system, that is, there must be more voltage loops to control the output voltage of the power converter. For the above reasons, it is necessary to develop a voltage-controlled power conversion device with islanding operation detection and the content thereof [invention] The main object of the present invention is to provide a negative=conversion device with islanding measurement and its control method. The period-frequency offset unit generates a frequency offset of the output voltage of a distributed power system, and has the effect of maintaining the output current of the distributed power system as a low harmonic distortion rate under normal operating conditions. The electric switch device and the control method thereof for the purpose of the raw material-feeding and so-called turning detection have the effects of controlling the health and phase of the power converter by using only a single loop controller 201015822. The objective is to provide an electric device with island operation detection and a control method thereof, which has the effect of making the output electromigration of the power conversion device not affected by the chopping voltage of its DC terminal. Another aspect of the invention

In order to achieve the aforementioned object, the technical means to which the present invention is applied includes a power conversion device with a lone & and a control method thereof, which includes an electric f-converter and a control circuit. The power converter has a DC terminal and a power electronic switch group, wherein the DC terminal is connected to the DC power supply via the link-inductor, and the AC terminal is connected to the power electronic switch group. To the AC power supply and a load of the power distribution system. The circuit has a first voltage detector, a power control unit, a frequency offset unit, a first-adder, a pulse width modulation circuit, and a drive circuit. The first voltage detector system The load voltage of the load is detected and connected to the power control unit and the frequency offset unit; the power control unit and the frequency offset unit are separately assigned a power report number and a frequency offset signal; and the first adder The input end is connected to the power control unit and the frequency offset unit 7L′ and the output end of the first addition method|| is modulated by the pulse width modulation circuit and then connected to the driving power rail to generate a power electronic switch of the power converter. The group of drivers (four); the (four) circuit is connected to the power converter for power electronics. Wherein, the fresh bias element has a band pass filter, and the frequency offset signal is one of the load voltages, and the non-basic wave frequency component group is generated by the itm slit and amplified, and the center band pass filter is centered. Close but not equal to the basic wave frequency of the crane. Therefore, the power conversion device with the island operation debt test of the present invention and the 201015822 method thereof can improve the '1 circuit complexity of the conventional island-running power conversion device. The above and other objects, features, and advantages will be more apparent. The following detailed description of the preferred embodiments of the present invention

G ” month refers to the first diagram, and the lining shows the system architecture 2 diagram of the isolated island operating power conversion device of the present invention used in a distributed power generation system. As shown in FIG. 1 , an AC power source j Connected to a load 3 via a first electromagnetic switch to provide a fixed frequency and a fixed amplitude of AC and = to the load 3, and ~ distributed power system 2 via - link inductor 4 a second electromagnetic switch 6 Connected to the load 3, or connected to the AC power source via the first power unit. The distributed power system 2 includes an outflow, a source 20, a storage capacitor 21, a power converter 22, and a power transmission pool. ;, wave device 23. Among them, the DC power source 20 can be selected from the solar power; the smoldering battery, the wind power generator after the AC/DC conversion or other energy storage capacitors are connected in parallel to the DC Wei 20, The DC power is rotated by the DC power supply; the power converter 22 includes a DC terminal and a current terminal, and the DC terminal is connected in parallel to the storage capacitor 21 to filter the power supply. The generated DC power is converted into an AC power; The device 23 is composed of a filter capacitor 231 and a filter inductor 232, and the turn-off chopper 23 is connected between the AC terminal of the power converter 22 and the link inductance= to eliminate the output of the power converter 22. Frequency switching noise. By means, the AC power generated by the distributed power system 2 is supplied to the load 3 via the link, or the power can be injected into the AC power supply. More specifically, the power converter 22 Having a power electronic switch group 221, wherein the two DC terminals of the power electronic switch group 221 are connected to the two-wheel output terminal of the DC power source, and the two power terminals of the power electronic switch group 221 are connected to the output filter and the wave filter The 23 bis input terminal is connected; and a control circuit 7 is connected to the power electronic switch group 221 of the power converter 22. Thereby, the power converter 22 is controlled by the control f path 7 to be output by the DC power source 2G.钱 The money electric energy is converted into an alternating current through the (four) wave H 23 and the bonding inductor 4 to provide the load 3, or can be injected into the alternating current power source j. In addition, although the power electronic switch group 221 shown in Fig. 1 Full bridge The structure 'only the power electronic switch group 221 can also be changed to the half-bridge architecture to achieve the purpose of power conversion. Please refer to FIG. 1 again, the AC power supply 1 and the distributed power supply system 2 respectively pass the first electromagnetic switch 5 And forming a parallel connection with the second electromagnetic switch 6 to jointly provide a load voltage to the load 3 for supplying power. Since the first electromagnetic switch 5 is connected between the alternating current power source 1 and the load 3, the first An electromagnetic switch 5 can control the load 3 and the AC power source 1 to be connected in parallel or disconnected; similarly, since the second electromagnetic switch 6 is connected between the distributed power system 2 and the load 3, the second electromagnetic The switch 6 can control the load 3 and the distributed power system 2 to be connected in parallel or disconnected from each other. The first electromagnetic switch 5 and the second electromagnetic switch 6 can be selected as a solid electromagnetic switch or other type of switch. In addition, the power converter 22 is a voltage-controlled power converter, and the distributed power supply system can be simultaneously obtained by adding a vertical vector to the voltage of the alternating current power source 1. The amplitude and phase of the wheel (four) voltage of the AC terminal of the power converter 22. = The power converter 22 only needs to adopt single-loop control to control the amplitude of the vertical vector, so that the power conversion core can generate an output current in phase with the voltage of the AC 1 and the amplitude of the output of the head power conversion H22 Will be proportional to the size of the (four) straight vector. In summary, the amplitude of the vertical vector will provide the actual power output of the distributed surface H, and according to the system architecture disclosed above, the vertical vector is the vector of the voltage of the inductor 4.

Referring to Fig. 2, it is shown in Fig. 2 that the first embodiment of the present invention has an islanding operation. The control circuit 7 includes a - first voltage detection H 7G, a power control unit 7 - a frequency offset unit 72, a - adder 73, a pulse width modulation [pwM] circuit 74 and a drive circuit 75, The power control unit 71 has a first band pass wave waver 71-phase shift circuit 712, a multiplier claw' and a second adder 714, and the frequency offset unit 72 has a subtractor 721, a The second band pass filter 722 and a first amplifier 723. The power converter 22 of the power conversion apparatus of the present invention employs a current indirect control voltage control method, and the reference signal generated by the control circuit 7 includes a power control signal S and a frequency offset signal I. The power control signal S! is used to determine the basic wave power amount sent by the distributed power system 2, and the distributed power system 2 outputs a sine wave current in phase with the voltage of the AC power source 1, that is, The power control signal Si is a sine wave signal having a fundamental wave frequency; and the frequency offset signal Sz is used to offset the frequency of the load 3 voltage after the AC power source i fails to detect the distributed power generation system- —13 — 201015822 Whether the island operation phenomenon occurs, but not equal to the frequency of the AC power transfer 信. Referring again to Figure 2, the connection and operation of the components of the present circuit 7 are controlled by $: The 7° system is for detecting the load... the first is connected to the power control unit 71, and the power control signal s is generated by ???=71.

Connected to 哕 (4) 抱 f The first electrical detector 70 is also connected = fresh offset m so that the frequency offset unit 7 shifts the frequency s2 by the frequency. Then, the power control signal, S! and the frequency offset sms are added to the reference signal of the power converter u by the first adder (4) connected to the power ^= and the frequency offset unit 72, and the reference signal of the power converter u is generated, and The reference money is connected to the pulse width modulation signal of the p-view circuit 74 in the present fiscal year, and transmitted to the pWM circuit % for modulation. Finally, the PWM circuit 74 sends the output to the drive circuit 75 to generate a drive signal for the power electronic switch bank 221 of the power converter 22. More specifically, in the power control unit 71, the first band pass filter 711 is connected to the output of the voltage detector 70 to send the detected load voltage to the first band pass filter. The center frequency of the first band pass filter 711 is the fundamental wave frequency of the AC power source 1, and an output end of the first band pass filter 711 is connected to one input end of the phase shift circuit 712, so that The first band pass filter 711 outputs a fundamental wave component of the load voltage and sends the fundamental wave component to the phase shift circuit 712, wherein the fundamental wave component output by the first band pass filter 711 is a sine wave signal, and the sine wave Signal 201015822 The frequency of the source 1 is the same frequency; the phase shift circuit 712 is a two-pass filter lit multiplier 713 'and the phase shift circuit 712 passes the first multiplier jaw; the wave signal is phase shifted by 9 degrees. The multiplier 713 multiplies the sine wave signal ...^° after the phase shift of 90 degrees to obtain a vertical vector signal, and the vertical direction= is a value of 90 degrees Celsius Vertical vector * υ^^& the amplitude of the output current of the distributed m system 2

And determining the actual amount of power of the decentralized power supply pure 2 output; the second input end of the second adder 714 is connected to the output terminal of the first electrical recording (4) and the multiplier 713 to load the load voltage The power vector control signal Si is obtained by adding the vertical vector signal, and is outputted by one of the second adders 714. Wherein the amplitude signal is proportional to the energy generated by the DC power source 20, and the output of the second adder 714 is the output of the power control unit 71. In addition, in the frequency offset unit 72, the wheel-in terminal of the subtractor 721 is also connected to the voltage detection tan 7 , and the other wheel-in terminal of the subtractor 721 is connected to the first-band pass An output of the filter 711, so that the subtractor 721 subtracts the load voltage from its fundamental wave component, and the output of the subtractor 721 outputs a non-basic wave frequency component of the load voltage; the second band pass filter The input end of the 722 is connected to the round output end of the subtractor 721, and the center frequency of the second band pass wave waver 722 is close to but not equal to the fundamental wave frequency of the AC power source 1; the input end of the first amplifier 723 = the first The output of the second generation pass chopper 722 is connected, so that the non-fundamental frequency component of the load is filtered and then amplified, thereby obtaining 15 - 201015822 to the frequency offset signal Sr and by the first amplifier One of the 723 rounds of the output. The output of the first amplifier 723 is the output of the frequency offset • unit 72. Referring to FIGS. 1 and 2, the operation mode of the power conversion device with islanding detection according to the first embodiment of the present invention is as follows: when the power source 1 is normally powered, the voltage of the AC power source is For this negative ^ 3: load voltage. Since the AC power source 1 is a very strong AC voltage ❹ #, the voltage is not laid out, and the voltage thereof does not include the center frequency of the second band pass filter and the wave filter 722 in the control circuit 7. Voltage ^. At this time, the non-basic wave frequency component of the load voltage passes through the second band, and the value of the frequency offset signal S2 generated after the filter 722 and the first amplifier 723 is extremely small. Therefore, the output current of the distributed power supply system 2 It is hardly affected by the frequency offset signal S2, so that the output current of the distributed power system 2 can maintain the total harmonic distortion rate lower than the regulatory standard. Under this condition, the power control signal Si of the power conversion H 22 is the main reference signal. On the other hand, when the AC power supply 1 cannot be powered normally, the strong parent voltage source does not exist, so that the load 3 cannot obtain the voltage of the mouth-set frequency, thus causing the distributed power system 2 to be powered by the single power supply. The islanding phenomenon occurs to the load 3. At this time, since the robustness of the split type power supply system 2 is low, the frequency 2 offset money S2 generated by the control circuit 7 is amplified, which not only causes the output power I of the intersection of the power conversion g 22 (ie, At this time, the word "load voltage" deviates from the frequency of the power supply 1 and the frequency offset signal S2 is detected when the first voltage detector 70 continuously detects the load power I having the offset frequency. It will also continue to zoom in on 201015822, further shifting the frequency of the power converter 22 away from the AC power source i until the frequency of the bulk = house is more efficient. 'Reading and cutting the system 2, please refer to Figure 3, the line shows the hair: the control structure of the island running pulse control circuit schematic circuit 7, benefit... ❹ 电路 circuit 7 another - chopper suppression signal &. Since the power converter 22 of the = type adopts a variable; the heart = force = the tank, the tank is determined by the modulation signal and the DC power of the DC terminal of the electric unit 22. however

2; output - the basic wave current, in addition to the - fundamental wave real power = = ^ = times the fundamental wave frequency of the instantaneous power, it will cause - twice the fundamental wave frequency of the chopping voltage in the power converter U, and The continuous voltage is caused by the direct current of the DC terminal of the power converter 22. In addition, the DC voltage of the power converter 22 may also be affected by the variation of the DC power source 20. However, 'the output voltage of the AC terminal of the power converter 22 is preferably proportional to the reference signal of the power converter 22 for the voltage-controlled power converter 22 indirectly controlling the current, so as to achieve the power. The control signal Si causes the distributed power supply system 2 to generate a sine wave current in phase with the voltage of the AC power supply 1, and to shift the frequency of the voltage of the load 3 by the frequency offset signal S2, etc., and thus the power The output voltage of the AC terminal of converter 22 cannot be affected by the DC voltage at its DC terminal. According to this, the control circuit 7 of the second embodiment of the present invention does not directly input the PWM circuit 74 as the pulse width modulation signal -17 - 201015822 by the reference signal, but first divides the reference signal by the 涟After the wave suppression voltage regulation signal &, the result of the division is used as the pulse width modulation signal of the pWM circuit 74, and the output voltage of the power conversion 22 is not affected by the DC voltage of the DC terminal. . The chopper suppression voltage regulation signal & is a signal proportional to the DC voltage of the power converter 22. Referring to FIG. 3 again, the control circuit 7 of the second embodiment of the present invention further includes a continuous wave suppression voltage stabilizing unit 76 and a divider 77, wherein the chopper suppression is compared to the first embodiment of the present invention. The voltage stabilizing unit 76 has a first, voltage detector 761 and a second amplifier 762. The chopper suppression voltage regulation unit 76 is configured to generate a chopper suppression voltage stabilization signal & the rain input device 77 bis input terminal is respectively connected to the first adder 73 and the chopper suppression stabilization element 76, In order to divide the reference signal containing the power control signal & and the frequency offset signal S2 by the chopper suppression voltage regulation signal, and the operation result of the divider 77 is input to the pWM circuit 74 to generate the power converter. 22 power electronic switch group mi ❹. More specifically, the second voltage detector 761 of the chopper suppression regulator unit 76 detects the DC voltage at the input of the power converter 22, and the first voltage detector 761 is connected to the second amplifier. 762, in order to send the detected DC voltage to the second amplifier 762; and the second amplifier 762 amplifies the detected DC power to generate the chopper suppression voltage signal S3. Thereby, it is possible to effectively suppress the wheeling voltage of the power converter 22 from being affected by the DC voltage variation at its DC terminal. In summary, compared with the conventional islanding operation detection power conversion device is prone to cause a large amount of current distortion, or because of the limitation of current distortion, the non-inductance caused by the amount of current distortion can not fully meet various The international control specification standard 'The power converter 22 with islanding detection of the present invention generates the frequency offset signal & via the second band pass filter 722 and the first amplifier 723, so that when the AC power source 1 is normally powered The value of the frequency offset signal & is extremely small without causing excessive distortion of the current of the power conversion II 22 and is circulated and continued by the first amplifier 723 when the AC power source 1 cannot be normally powered. By amplifying the frequency offset signal &, the frequency of the output ink of the distributed power system 2 can be effectively offset, and the islanding phenomenon of the distributed power system 2 is successfully detected. The rate control unit it 7i only needs to adopt a single-loop to generate the power control signal Si while controlling the amplitude and phase of the output voltage of the power converter 22; and the present invention further suppresses the voltage stabilization signal by the chopper. 3 effectively suppressing the output voltage of the power converter 22 from being affected by changes in the DC voltage at its DC terminal. The present invention has been disclosed by the above-described preferred embodiments, and it is not intended to limit the invention, and various modifications and changes to the above embodiments are possible without departing from the spirit and scope of the invention. The technical protection of the present invention is therefore defined by the scope of the patent application of the present invention. 201015822 [Circular Simple Description] Fig. 1 is a schematic diagram of the system architecture when the power conversion device with island operation detection is used in a distributed power generation system. Fig. 2 is a view showing the control structure of a control circuit of a power conversion device with island operation detection according to a first embodiment of the present invention. 3rd: A schematic diagram of a control structure of a control circuit of a power conversion device having an island operation system according to a second embodiment of the present invention. ❹ [Main component symbol description] 1 AC power supply 20 DC power supply 22 Power converter 23 Output filter 232 Wave inductance 4 Chain inductance 6 Second electromagnetic switch T Control circuit 71 Power control unit 712 Phase shift circuit 714 Second adder 721 Subtractor 723 first amplifier 74 pulse width modulation circuit

76 Chopper suppression regulator unit 2 Decentralized power system 21 Storage capacitor 221 Power electronic switch group 231 Filter capacitor 3 Load 5 First electromagnetic switch 7 Control circuit 70 First voltage detector 711 First band pass filter 713 multiplication Transmitter 72 frequency offset unit 722 'second band pass filter 73 first adder 75 drive circuit 761 second voltage detector 201015822 762 second amplifier 77 divider Si power control signal s2 frequency offset signal S3 chopper suppression Regulated signal 〇❹ —21 —

Claims (1)

201015822 X. Patent application scope: 1 A power conversion device with island operation speculation, comprising: a power converter having a DC terminal, a technology terminal and a power electric switch group, the button is provided for Connecting the power electronic switch group to the continuous machine and the source, and the AC terminal is connected to the power electronic switch group via the output ferrite and the key inductor to the AC power supply and the load; and the control circuit has a - a first voltage detector, a power control unit frequency offset unit, a first adder, a pulse width modulation circuit, and a driving circuit 'the first voltage detector is configured to detect a load voltage of the load And connecting the power control unit and the frequency offset element, the power control unit and the frequency offset unit respectively output a power control signal and a frequency offset signal, wherein the second input end of the first adder is connected to the power control unit and the frequency An output end of the offset unit, and an output signal of the first adder is connected to an input end of the pulse width modulation circuit, and an output signal of the pulse width modulation circuit is sent to the driving circuit to generate a driving signal of the power electronic switch group of the power converter, and the driving circuit is connected to the power electronic switch group of the power converter; wherein the frequency offset unit has a band pass filter, and the frequency offset signal is the One of the load voltages is generated by the bandpass filter and amplified, and the center frequency of the bandpass filter is close to but not equal to the fundamental frequency of the AC power source. 2. The power conversion device with island operation detection according to claim 1 of the patent application scope, wherein the output filter through which the AC terminal of the power converter is connected to the AC power source and the load is a filter inductor And a set of 201015822 wave capacitance. 3. The power conversion device with island operation detection according to item 1 of the patent application scope, wherein the power control signal is a vertical vector signal and a sum of the load voltages, and the frequency of the vertical vector signal is the exchange The fundamental wave frequency of the power supply, and the phase of the vertical vector signal leads the load voltage by 90 degrees. 4. The power conversion device with island operation detection according to the application scope of the patent application, wherein the power control unit has a band pass filter connected to the first voltage detector and the power control unit The center frequency of the pass filter is the fundamental wave frequency of the parent current source to generate the fundamental wave component of the load voltage. 5. The power conversion device with islanding operation detection according to item 4 of the patent application scope, wherein the power control unit further has a phase shift circuit, a multiplier and a second adder 'one of the phase shift circuits The input end is connected to the wheel-out terminal of the band-pass filter of the power control unit, and the phase shift circuit sends the fundamental wave component of the load voltage to the multiplication method after 9-degree phase shift, and the secret II will be 9G. After the phase shift, the fundamental wave component of the load voltage is multiplied by the amplitude signal to obtain a vertical vector signal; the second input of the second adder is connected to the first voltage detector and the multiplier • The output terminal 'adds the load voltage to the vertical vector signal to obtain the power control signal. 6. The power conversion device of the island operation system according to claim 4, wherein the frequency offset unit further has a subtractor and a first amplifier. The input terminals of the subtractor are respectively connected to the first The voltage is detected at an output end of the 201015822 device and an output end of the band pass filter of the power control unit to subtract the load voltage from a fundamental wave component thereof, thereby generating a non-fundamental wave frequency component of the load voltage, and sending the component a band pass filter of the frequency offset unit; the first amplifier is coupled to an output of the band pass filter of the frequency offset unit to generate the frequency offset signal. 7. The power conversion device with island operation detection according to the application scope of the patent application, wherein the control circuit further comprises a chopper suppression voltage regulator unit and a divider, and the output of the first adder is After the divider is connected to the pulse width modulation circuit, the chopper suppression voltage regulator unit generates a chopper suppression voltage regulation indicator and is connected to the divider, and the divider outputs the output of the first adder The pulse width modulation circuit is sent after dividing the suppression voltage stabilization signal. 8. The power conversion device with an island running side according to claim 7 of the patent application scope, wherein the chopper suppression voltage stabilizing unit has a second voltage detector and a second amplifier, and the second voltage detector system Detecting a DC voltage of the DC terminal of the power converter and connecting to the second amplifier; the second amplifier amplifying the DC voltage detected by the second voltage detector and rotating the chopper suppression voltage stabilization signal. 9 A control method for a power conversion device with island operation detection, controlling a power electronic switch of a power converter through a control circuit and having an AC terminal for connection via a chain:: an exchange The power supply and a load, the control method comprises: cutting a first-voltage detector to detect the load voltage of the load, the load power to the power-to-power (four) unit and the rate 1 check - 24 - 201015822 The power control unit generates and outputs a power control signal; the frequency offset unit uses a band pass filter to perform the non-f local wave unwrapping of the load electric waste, and the round-off of the power supply (4) is amplified to Generating a frequency offset signal; and adding (4) the power (four) signal and the frequency offset signal, and the first-plus (2) outputting the output to the -drive circuit after being modulated by the pulse width modulation circuit, The driving signal of the electronic switch group of the power converter is generated; wherein the center frequency of the fresh offset unit is close to but not #(10). 10. The control method of the power conversion device with the island operation system according to claim 9 of the claim, wherein the power control unit filters the power control unit when the power control unit generates and outputs the power control unit. The load voltage is filtered, and the center frequency of the band pass filter of the discriminating unit is the fundamental wave frequency of the AC power source. ❹1 依 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 申请 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中 其中The fundamental wave component of the load voltage is phase-shifted by 9 degrees and sent to the -multiplier device. The multiplier multiplies the fundamental wave component of the load voltage after the 90-degree phase shift by the -amplitude signal to obtain a vertical The vector signal is sent to the =-adder, which adds the load voltage to the vertical vector 彳5 to obtain the power control_sound. ...in accordance with the patent system No. 9 or 1G series of isolated islands _ 贞 之 - 25 - 201015822 control method of power conversion device, wherein the frequency offset scatter at the frequency, the fresh offset unit The load is subtracted from the fundamental wave component of the payload, ^ ^ the non-basic wave frequency component of the carrier is sent to the frequency 2 bandpass filter, and a first amplifier amplifies the frequency offset single L bandpass filter The output of the device produces the frequency offset signal. 13 ❹ 14 ❹ According to the control method of the power conversion device with island operation detection according to claim 9 of the patent application scope, wherein the first addition (10) is connected to the pulse change view after passing through a divider, and The verification side voltage unit generates a chopper suppression voltage stabilization signal, and then divides the output of the first adder by the chopper suppression touch voltage signal by the divider to send the pulse width modulation circuit. According to the application of the special Wei (4) 13 rhyme to describe the power conversion device of the island transport (four) method (4) method of the towel in the suppression of the suspension unit to generate the chopper suppression suspension signal, the chopping (four) pressure unit with a second voltage Detecting ϋ detecting the DC voltage of the DC terminal of the power converter and, to the second amplifier, the second amplifier amplifying the DC voltage detected by the second voltage detector to obtain the voltage regulation signal .