TW201251295A - Five level power converter - Google Patents

Abstract

The present invention relates to a DC-AC power conversion five level power converter. Five level power converter of the present invention comprises a dual buck converter, a bridge power converter and a controller, which controls the dual buck type power converter to generate a DC three level pulse wide modulated voltage supplied to the bridge power converter, and controls switching of the bridge power converter with low frequency The DC three level pulse wide modulated voltage is further converted to an ac five level pulse wide modulated voltage, and generates a phase of the mains power system sine current for supplying mains power system. Five level power converter of the present invention uses electricity as conversion between direct current and alternating current for providing electricity conversion interface between the DC power and supply mains.

Description

201251295 VI. Description of the Invention: [Technical Field] [0001] The present invention relates to a fifth-order power converter, which is particularly useful in converting a power of a direct current power source into a sinusoidal current in phase with the commercial power. Inject electricity into the mains as a power conversion interface between the DC power supply and the mains. [Prior Art] [0002] In recent years, due to the high development of industry, not only the petrochemical energy on the earth has been rapidly depleted, but also the serious pollution and climate change of the global environment. In order to alleviate the serious impact of petrochemical energy on the environment, the international agreement on the Kyoto Protocol and the Copenhagen Accord to limit carbon dioxide emissions, and based on the pursuit of diversification of energy sources and the search for permanent energy, actively develop renewable energy and reduce power loss It has become an inevitable trend in the development of power systems, and has become an important research target in the world. Therefore, it is an urgent issue to find renewable energy to replace fossil fuel energy, and it has potential for development in renewable energy for power generation systems. There are solar energy, wind energy, hydropower, geothermal energy and biomass energy. Among them, solar energy and wind energy are relatively mature in power generation technology. Most of these new energy sources need to use the DC-AC power converter as the interface with the commercial power. The conventional DC-AC power converter comprises a half-bridge and a full-bridge type, and the half-bridge power converter is composed of a capacitor arm and a power electronic switch arm, and the peak value of the DC bus voltage must be higher than the peak value of the AC voltage. Twice, the output voltage level only contains two-order changes. The voltage change caused by each power electronic switch is the entire DC bus voltage, and the full-bridge power converter is composed of two power electronic switch arms. DC 100119312 Form No. A0101 Page 4 / Total 34 Page 1002032613-0 201251295 The peak of the bus voltage must be higher than the AC voltage peak, the power electronic switch switching mode is divided into bipolar and unipolar, bipolar switching mode its output voltage level Only two-order changes (positive and negative DC bus voltages) are included. The voltage change caused by each power electronic switch is twice the DC bus voltage, while the unipolar output voltage level includes a third-order change (positive DC). Bus voltage, zero and negative DC bus voltage), voltage change caused by each power electronic switch For DC bus voltage, whether it is a half-bridge or full-bridge power converter, it uses high-frequency switching to generate the desired voltage or current. Due to the non-ideal characteristics of the power electronic switch, switching loss will occur when switching, and the switching loss is proportional. In switching frequency, switching voltage and current, switching loss is the main part of power converter loss. In order to improve the efficiency of power converter, we must try to reduce the voltage of each switching of power electronic switch to reduce switching loss, and switch voltage every time. Lowering also reduces switching harmonics and electromagnetic interference, which reduces the output filter and EMI filtering capacity, further reducing circuit losses. The multi-step power converter can effectively reduce the voltage change of each switch of the power electronic switch, but the higher the order of the multi-stage power converter, the more the number of power electronic switches required, and the more complicated the control circuit is. Therefore, multi-stage power converters need to consider the performance and cost to design the output voltage level in practical applications. The conventional multi-stage power converter can be divided into a diode clamp type, a flywheel capacitor type and a series bridge type according to the circuit architecture, and the circuit structure thereof is as shown in the first figure. The first figure (A) shows a single-phase diode-clamped third-order power converter (hereinafter referred to as a clamp converter), whose output voltage level contains a third-order change, each time the power electronic switch is switched. The voltage change is the voltage of a capacitor, clamp type 100119312 Form No. A0101 Page 5 / Total 34 Page 1002032613-0 201251295 The switching control of the power electronic switch of the converter must take into account the voltage equalization of the two power capacitors, especially It is difficult to achieve the voltage equalization at light load. If you want to use the clamp converter to get the fifth-order output voltage, you must add several power electronic switches and capacitors, which makes the circuit complicated and the voltage regulation of the capacitor is more difficult. The first figure (B) shows a single-phase flywheel capacitive third-order power converter (hereinafter referred to as a flywheel converter), whose output voltage level includes a third-order change, and the voltage change caused by each power electronic switch is changed. For the voltage of a capacitor, the switching combination of the power electronic switch must take into account the charging and discharging of the capacitor voltage, as a voltage regulator control of the capacitor voltage, so the control is more complicated. If the flywheel converter is to obtain a fifth-order output voltage, It is necessary to add several power electronic switches and capacitors, which complicates the circuit and makes the voltage regulation of the capacitor more difficult. The circuit structure of the single-phase series bridge multi-stage power converter is shown in the first figure (C), and its output voltage level includes a fifth-order change. However, since it uses two independent DC buss, two groups are required. Independent DC voltage source 〇 In view of the above-mentioned deficiencies in the prior art, the applicant has carefully developed and researched a fifth-order power converter that can be connected to the mains system to generate a new energy system. The DC power is converted into an AC fifth-order pulse width modulation voltage to generate a sinusoidal current with the same phase as the commercial power, and is converted into a DC to AC power conversion function as an electrical energy conversion interface between the DC power source and the utility power. The fifth-order power converter developed by the invention uses only six power electronic switches, and since only two of the power electronic switches adopt high-frequency switching, the two power electronic switches adopt high-frequency switching to achieve DC stability. Pressure and voltage equalization, compared with the conventional multi-stage power converter, can effectively simplify the circuit architecture and control the circuit of 100119312 Form No. A0101 Page 6 of 341002032613-0 201251295 to improve the efficiency of power conversion. SUMMARY OF THE INVENTION [0003] Ο

The main purpose of the present invention is to provide a fifth-order power converter, which is electrically connected to a DC power supply and a mains system, and mainly provides conversion of electric energy of a DC power source into an AC power, and the fifth-order power converter operates. An alternating fifth-order pulse width modulation voltage is generated, and a sinusoidal current with the same phase as the commercial power is injected into the commercial power as an electrical energy conversion interface between the direct current power source and the commercial power. In order to achieve the above object, the fifth-order power converter of the present invention comprises a dual buck converter and a bridge power converter and a controller, and the controller is used to control the dual buck-type power converter to generate a three-way power converter. The step width modulation voltage is supplied to the bridge power converter, and the bridge power converter is controlled to perform low frequency switching in synchronization with the mains voltage, and the DC third-order pulse width modulation voltage is further converted into an AC fifth-order pulse width modulation. The voltage is varied and a sinusoidal current in phase with the mains voltage is generated for injection into the mains system. In the preferred embodiment of the fifth-order power converter of the present invention, only six power electronic switches are used, and the controller can directly achieve the voltage regulation and voltage equalization of the DC terminal thereof, and since only two of the power electronic switches are used High-frequency switching can effectively simplify the circuit architecture and control circuit, reduce switching losses, reduce output filter inductors and electromagnetic interference, and thus improve power conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more <RTIgt; understood</RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; 0 [0004] 201251295 The drawings are described in detail below. The second figure shows an embodiment of a fifth-order power converter (A) of the present invention. The fifth-order power converter (A) comprises: an input terminal group (1): the input terminal group (1) Provides an electrical connection to the DC power supply. A dual step-down power converter (2) includes: an upper buck converter (21): the upper buck converter (21) includes a first input terminal (211) and a first output terminal (212) And the first input terminal (211) is electrically connected to the input terminal group (1). The buck converter (22): the buck converter (22) includes a second input terminal (221) and a second output terminal (222), the second input terminal (221) is electrically connected to the input The end group (1), and the down-converter (22) is electrically connected to the upper buck converter (21). A bridge type power converter (3): The bridge type power converter (3) is electrically connected to the first output end (212) and the second output end (222), respectively. A filter (4): The filter (4) is electrically connected to the bridge power converter (3). An output terminal group (5): The output terminal group (5) is electrically connected to the filter (4) to provide parallel connection with a mains system (8). A controller (6): The controller (8) is electrically connected to the dual buck power converter (2) and the bridge power converter (3), respectively. Form No. A0101 Page 8 of 34 201251295 The present invention controls the dual buck power converter (2) by the controller (6) to enter the dual buck power converter (2) The voltage of the DC power source is converted into a DC third-order pulse width modulation voltage to supply the bridge power converter (3), and the bridge power converter (3) is controlled to be low frequency synchronized with the voltage of the utility system (8) Switching, the DC third-order pulse width modulation voltage is further converted into an AC fifth-order pulse width modulation voltage, and a sine wave current in phase with the voltage of the mains system (8) is injected into the mains.

The third figure shows a preferred embodiment of the filter (4). Please refer to the third figure (a) in conjunction with the second figure. The filter (4) includes an inductor (41) 'the inductor (41) One end is electrically connected to the output end group (5), and the other end is electrically connected to the bridge power converter (3), so that the filter (4) is a first-order low-pass filter. Referring to FIG. 3(b), the filter (4) further includes a filter capacitor (42), and the filter capacitor (42) is connected in parallel to the output end group (5) to make the filter (4) ) is a second-order low-pass filter.

Referring to the second embodiment, the dual buck power converter (2) and the bridge power converter (3) are preferred embodiments, the upper buck converter (21) and the down voltage conversion The device (22) is electrically connected to generate a first terminal (23) 'and' the upper buck converter (21) comprises: a first power electronic switch (213): electrically connected to the first input (211) and the first output (212). a first diode (214): the cathode is electrically connected to the first output end (212). The anode is electrically connected to the first end point (23), a first capacitor (215): electrically connected to the first An input (211) and the first end (23). 100119312 The down-converter (22) comprises: form number A0101, page 9 / total 34 pages 1002032613-0 201251295 first-power electronic switch (223): electrically connected to the second input terminal (221) and the first Two outputs (222). The pole body (224): the anode is electrically connected to the second output end (222), and the cathode is electrically connected to the first end point (23). The first capacitor (225) is electrically connected to the second input end (221) and the first end point (23), respectively. The bridge power converter (3) includes: a first bridge arm (31) and a second bridge arm (32), the first bridge arm (31) is parallel to the first bridge arm (32) to define a a first contact (33) and a second contact (34), wherein the first contact (33) and the second contact (34) are electrically connected to the first output terminal (212) and the first a second output end (222), the first bridge arm (31) includes a third power electronic switch (311) and a fourth power electronic switch (312), the third power electronic switch (311) is a first wire (313) electrically connecting the fourth power electronic switch (312); the second bridge arm (32) includes a fifth power electronic switch (321) and a sixth power electronic switch (322), the fifth power electronic The switch (321) is electrically connected to the sixth power electronic switch (322) by a second electric wire (323), and the filter (4) is electrically connected to the first electric wire (313) and the second electric wire (323) respectively. ). And the controller (6) is electrically connected to the first to sixth power electronic switches (213, 223, 311, 312, 321, 322), respectively. In the fifth-order power converter (A) of the present invention, the first and second capacitors (215, 225) have nearly the same capacitance value, and are connected in series to the DC power supply (7) 'the DC power supply ( 7) The voltage is Vdc, so the voltage values of the first and second DC capacitors (215, 225) are nearly the same, about Vdc/2. The fifth-order power converter (A) uses the controller (6) in the city 100119312 form number A010〗 Page 10 / Total 34 page 1002032613-0 201251295 The voltage of the electric system (8) is half a cycle, and the control is One to sixth power electronic switches (213, 223, 311, 312, 321, 322) to generate four switching modes, the fourth figure shows an equivalent circuit for its operation, when the voltage of the mains system (8) is During the positive half cycle, as shown in the fourth diagram (a), the third and sixth power electronic switches (311, 322) are turned on, and the fourth and fifth power electronic switches (312, 321) are worn, the pair Buck power converter

(2) the first power electronic switch (213) is turned on, the second power electronic switch (223) is turned off, and the discharge current of the first capacitor (215) flows through the first power electronic switch (213), the first a three-power electronic switch (311), the sixth power electronic switch (322) and the second diode (224), wherein the output voltage of the dual buck power converter (2) is Vdc/2, and The output voltage of the bridge power converter (3) is also vdc/2; when the mode is switched, the second power electronic switch (223) is turned on as shown in the fourth figure (b), and the first power electronic switch ( 213) cutting off, causing a discharge current of the second DC capacitor (225) to flow through the second power electronic switch (223), the third power electronic switch (311), the sixth power electronic switch (322) and the

a diode (214), the output voltage of the dual buck power converter (2) is Vdc/2, and the output voltage of the bridge power converter (3) is also Vdc/2, switching mode At the third time, as shown in the fourth figure (c), the first power electronic switch (213) and the second power electronic switch (223) are both turned off, so that the first diode (214), the second two The pole body (224), the third power electronic switch (311) and the sixth power electronic switch (322) are turned on, and at this time, the output voltage of the double buck power converter (2) is 〇, and the bridge type The output voltage of the power converter (3) is also 〇; when the mode is switched four times, as shown in the fourth figure (d), the first power electronic switch (213) and the second power electronic switch (223) are both turned on, The discharge currents of the first and second capacitors (215, 100119312 Form No. A0101, page 11/34 pages 1002032613-201251295 225) simultaneously flow through the first power electronic switch (2i3), the first power switch (223) The third power electronic switch (311) and the sixth power electronic switch (322), the double step-down power Converter (2) of the output voltage Vdc, and (3) the output voltage of the bridge power converter also Vdc. The power electronic switch of the present invention is not limited to the FET, but may be an IGBT or a BJT. For the present invention, the power electronic switches are preferably MOSFETs. The fifth-order power converter (A) uses the controller (6) to generate four switching modes when the voltage of the mains system (8) is negative half cycle; the fifth figure shows the equivalent circuit for its operation, when When the voltage of the mains system (8) is a negative half cycle, the fourth and fifth power electronic switches (312, 321) are turned on, and the second and sixth power electronic switches (311, 322) are turned off, and the switching mode is At a moment, as shown in the fifth diagram (a), the first power electronic switch (213) is turned on, and the second power electronic switch (223) is turned off, so that the discharge current of the first capacitor (21 5) flows through the first a power electronic switch (213), the fifth power electronic switch (321) 'the fourth power electronic switch (312) and the second diode (224), the double step-down power converter (2) The output voltage of the bridge is Vdc/2' and the output voltage of the bridge power converter (3) is Ο -Vdc/2. When the mode is switched two, as shown in the fifth figure (b), the second power electronic switch ( 223) conducting, the first power electronic switch (213) is turned off, and causing a discharge current of the second capacitor (225) to flow through the first a power electronic switch (223), the fifth power electronic switch (321), the fourth power electronic switch (312) and the first diode (214), the double step-down power converter (2) The output voltage is Vdc/2, and the output voltage of the bridge power converter (3) is -Vdc/2; when the mode is switched three, as shown in the fifth figure (c), the first power electronic switch (213) With the second power electronic switch 100119312 Form No. A0101 Page 12 / Total 34 Page 1002032613-0 201251295

(223) are both turned off, such that the first diode (214), the second diode (224), the fifth power electronic switch (321) and the fourth power electronic switch (312) are turned on, The output voltage of the dual buck power converter (2) is 0, and the output power of the bridge power converter (8) is also 〇; when the switching mode is four, as shown in the fifth figure (d), the first The power electronic switch (213) and the second power electronic switch (223) are both turned on, so that the discharge currents of the first and second capacitors (215, 225) simultaneously flow through the first power electronic switch (213), a second power electronic switch (223), the fifth power electronic switch (321) and the fourth power electronic switch (312), wherein the output voltage of the dual buck power converter (2) is Vdc, and the The bridge power converter (3) has an output voltage of -Vdc.

Combining the above-mentioned five-step power converter (A), the output voltage of the double-buck power converter (2) is a DC voltage having a third-order variation such as Vdc, Vdc/2, and 0, and the bridge power is The converter (3) is switched in synchronization with the voltage of the mains system (8), and the bridge power converter (3) can further generate Vdc, Vdc/2, 0, -Vdc/2, -Vdc, etc. The varying AC output voltage' is therefore a fifth-order power converter (A). Referring again to the preferred embodiment of the fifth-order power converter (A) of the present invention shown in the second figure, the cancer of the first power electronic switch (213) and the second power electronic switch (223) must follow The voltage amplitude of the mains system (8) changes. When the absolute value of the voltage of the mains system (8) is less than vdc/2, the controller (6) controls the first power electronic switch (213) or the second power electronic switch (2 2 3) to perform high frequency switching. However, only one of the switches can be turned on at the same time. When the first power electronic switch (213) or the second power electronic switch (223) is turned on, the bridge power converter (3) can generate an output voltage of about +Vdc/2 or -Vdc/2, whose output voltage is positive or negative 100119312 Form No. A0101 Page 13 / Total 34 Page 1002032613-0 201251295 This third to sixth power by the bridge power converter (3) The state of the electronic switch (311, 312, 321, 322) is determined, at which time the absolute value of the output current of the fifth-order power converter (A) will rise, when the first power electronic switch (213) and the second power electronic When the switch (223) is turned off, the output voltage of the bridge power converter (3) is 0, and the absolute value of the output current of the fifth-order power converter (A) will decrease, thereby controlling the first power electronic switch ( 21 3) performing high frequency cutting with one of the second power electronic switches (223) The output current of the fifth-order power converter (A) can be controlled to follow an absolute value of a reference current signal, which is the desired output current of the fifth-order power converter (A) and the first power electronic switch (21 3) and the second power electronic switch (223) for high frequency switching depends on the voltages of the first and second capacitors (215, 225), if the first capacitor (215) voltage is higher than the a second capacitor (225) voltage, the first power electronic switch (213) is switched at a high frequency, and the first capacitor (215) releases power; otherwise, the second capacitor (225) has a higher voltage than the first capacitor (215), the second power electronic switch (223) is switched at a high frequency, and the second capacitor (225) is discharged, so that the voltage values of the first and second capacitors (215, 225) can be equalized. . Referring to the preferred embodiment of the fifth-order power converter (A) of the present invention shown in the second figure, when the absolute value of the voltage of the mains system (8) is higher than Vdc/2, the controller (6) is utilized. Controlling one of the first power electronic switch (213) and the second power electronic switch (223) for high frequency switching, and the other power electronic switch is always turned on when the first power electronic switch (21 3) When the second power electronic switch (223) is turned on, the bridge power converter (3) can generate an output voltage +Vdc or -Vdc, and its output voltage is positive or negative by the bridge power converter (3) The third to sixth power 100119312 Form No. A0101 Page 14 / Total 34 page ιηη9 201251295 The state of the electronic switch (311, 312, 321, 322) is determined, at this time, the fifth-order power turns (four) (Α) output current The absolute value will rise. When one of the first power electronic switch (213) and the second power electronic switch (223) is off, the output voltage of the bridge power converter (3) is about + Vdc/2. Or -Vdc/2, whose output voltage is positive or negative by the bridge power converter (3) Three to the sixth power electronic switches (311,3i2 32i Ο

The state of 322) determines that the absolute value of the output current of the fifth-order power converter (4) will decrease, so that the first power electronic switch (213) and the second power electronic switch (223) are controlled to perform high-frequency switching. The output power of the fifth-order power converter (1) can be controlled to follow the absolute value of the reference current signal, and the first power electronic switch (213) and the second power electronic switch (223) are switched to the high frequency. Depending on the voltage values of the first and second capacitors (215, 225), if the voltage of the first capacitor (215) is higher than the voltage of the second capacitor (225), the second power electronic switch (223) performs high frequency switching. The first capacitor (215) is released longer than the second capacitor (225); conversely, the second capacitor (225) is higher than the first capacitor (215), the first power electronic switch ( 213) For high frequency switching, the second capacitor (225) is released longer than the first capacitor (215), so that the equalization of the first and second capacitors (215, 225) can be achieved. It can be seen from the above description that the preferred embodiment of the dual step power converter (2) of the present invention utilizes the first power electronic switch (213) and the fifth power converter (A) Switching of the second power electronic switch (223) can generate a three-dimensional pulse width modulation voltage to the bridge power converter (3)' and achieve equal voltage values of the first and second capacitors (215, 225) And the preferred embodiment of the bridge power converter (3) adopts a low frequency switching synchronized with the voltage of the 100119312 form number A0101 page 15 / page 34 1002032613-0 201251295 utility system (8) to The third-order pulse width modulation voltage is further converted into an AC fifth-order pulse width modulation voltage, and the output current of the fifth-order power converter (A) is controlled to follow a reference current signal. Therefore, the fifth-order power converter (A) is applied to a regenerative power generation system by a preferred embodiment of the dual-drop power converter (2) and a preferred embodiment of the bridge power converter (3) The regenerative power generation system is coupled to the fifth-order power converter (A) as the DC power source (7), and the reference current signal is a sine wave in phase with the mains system voltage, and thus the fifth-order power conversion The device (A) can output a sinusoidal current in phase with the voltage of the mains system (8). The fifth-order power converter (A) developed by the present invention uses only six power electronic switches, and since only the first and second power electronic switches (213, 223) of the dual-buck power converter (2) Using high frequency switching, and using the first and second power electronic switches (213 '223) to achieve DC voltage regulation and voltage equalization using high frequency switching, and the third to the third of the bridge power converters (3) The six-power electronic switch (311, 312 321 3 2 2 ) is compared with the multi-stage power converter of the conventional power system (8), and the fifth-order power converter developed by the present invention is compared with the conventional multi-stage power converter. (A) can effectively simplify the circuit architecture and control circuit, and improve the efficiency of power conversion. Figure 6 shows a preferred embodiment of the controller (6) of the fifth-order power converter (1) of the present invention, the controller (6) comprising: a first voltage detector (6a): 〇 the first - The electrical detector (6a) is electrically connected to the first capacitor (215) to provide a voltage value for detecting, and the first voltage detector and the second voltage detector (6b) are obtained: 100119312. The output device (6b) is electrically connected to the second capacitor form number A0101, page 16 / page 34, 1002032613-0 201251295 (225) to provide a voltage value for detecting a second voltage signal. An adder (61): the adder (61) is electrically connected to the first and second voltage detectors (6a, 6b) respectively, and is configured to receive the first and second voltage signals and perform addition A third voltage signal is obtained. a first subtractor (62): the first subtractor (62) is electrically connected to the adder (61), and is configured to receive the third voltage signal and subtract a predetermined voltage signal to obtain a first Four voltage signals.

A proportional integral controller (63): the proportional integral controller (63) is electrically connected to the first subtractor (62), and provides a amplitude signal for receiving the fourth voltage signal to generate a reference current. A third voltage detector (6C) is electrically connected to the mains system (8) for detecting the voltage 'to obtain a mains signal. A signal generator (64):

The signal generator (64) is electrically coupled to the third voltage detector (6c) and provides for receiving the utility signal to generate a unit sine wave signal in phase with the voltage of the utility system (8). a multiplier (65): the multiplier (65) is electrically connected to the proportional integral controller (63) and the 彳§ generator (64) respectively, and provides an amplitude signal for receiving the reference current and the unit sine wave The signals are multiplied to produce a reference current signal. A current detector (6d): 100119312 Form No. A0101 Page 17 of 34 1002032613-0 201251295 and ESP e(6d) is electrically connected to the output endpoint group (5) to provide detection of the fifth-order power The current of the converter (1) is turned on to obtain an output current signal. a first subtractor (6 6 ): the second subtractor (66) is electrically connected to the multiplier (8) and the current detector (6d), and is configured to receive the reference current signal and the output current signal and perform Subtraction, and get - error signal. - Current controller (67): &quot;Hai current controller (67) is electrically connected to the second subtractor (66) to provide closed loop control for receiving the error signal for current And obtaining a control signal. A pulse width modulation circuit (68): the pulse width modulation circuit (68) is electrically connected to the current controller (67), and is configured to receive the control signal and convert it into a pulse width modulation signal. - a third subtractor (69): the third subtractor (69) is electrically connected to the first and second voltage detectors (6a, 6b) respectively, and is configured to receive the first and The second voltage signal is subtracted to obtain a voltage difference signal. The first mode selection circuit (60): the mode selection circuit (60) is electrically connected to the pulse width modulation circuit (68) and the first a three-subtractor (69) and a third voltage detector (6c) for generating a first driving signal and a second driving signal, The output is electrically connected to the first power electronic switch (213) and the second power electronic switch (223) to control the operation of the first and second power electronic switches (213, 223). 6e): 100119312 Form No. A0101 Page 18 of 34 1002032613-0 201251295 The comparator (6e) is electrically connected to the third voltage detector (6c) to generate the second, fourth, fifth and a driving signal, wherein the output is electrically connected to the third to sixth power electronic switches (311, 312, 321, 322) to control the third to sixth power electronic switches (311, 312, 321 '322 The fifth-order power converter (A) is used to regulate the voltage of the first and second capacitors (215, 225) and generate a sinusoidal current injection in phase with the voltage of the mains system (8). The mains system, please refer to the control block shown in the sixth figure, and the voltage of the first and second capacitors (215, 225) passes through the first and second voltage detectors as shown in the second figure. (6a, 6b) detected and added by the adder (61), the third voltage signal is obtained and The preset voltage signal set in the first subtractor (62) is subtracted to obtain the fourth voltage signal, and then sent to the proportional integral controller (63) to generate an amplitude signal of the reference current signal, in order to obtain a The sinusoidal current of the same phase of the voltage of the mains system (8), the voltage of the mains system (8) is detected by the third voltage detector (6c) and sent to the signal generator (64) to generate a The unit sine wave signal of the same phase of the voltage of the mains system (8) is multiplied by the amplitude sine wave signal and sent to the multiplier (65) to obtain the reference current signal, the fifth-order power converter ( A) the output current is detected by the current detector (6d), and the output current signal is obtained, and then the reference current signal is subtracted by the second subtractor (66), and an error signal is sent to the current. The controller (67) is used for closed loop control of current to obtain a control signal. The output of the current controller (67) is sent to a pulse width modulation circuit (68) to generate a pulse width modulation signal, since the first power electronic switch (213) and the second power electronic switch (223) must be simultaneously The first and 100119312 form number A0101 page 19 / total page 34 1002032613-0 201251295 the voltage equalization of the second capacitor (21 5, 2 2 5 ), and its switching state must follow the voltage amplitude variation of the mains system (8), Therefore, the first and second voltage signals are subtracted by a third subtractor (69) to obtain a voltage difference signal, and then the β hai electric difference is sent, the sXuan electric power siL number and the pulse width modulation signal are sent to a mode selection circuit (60), the mode selection circuit (60) generates the first and first driving signals, and controls the actuation of the first and second power electronic switches (213, 223) to The first and second capacitors (215, 225) have equal voltage values, thereby causing the dual buck power converter (2) to generate a DC three-order pulse width modulation voltage for the bridge power converter. The third to sixth power electronic switches of the power converter (3) (311, 312, 32b 322 Using a low frequency switching synchronized with the voltage of the mains system (8), the fifth voltage signal detected by the third voltage detector (6c) is sent to a comparator (6e) to generate the third to a sixth driving signal for causing the comparator (6e) to control the actuation of the third to sixth power electronic switches (311, 312, 321 '322), thereby controlling the bridge power converter (3) to interact with the utility system ( 8) Low-frequency switching of voltage synchronization, further converting the DC third-order pulse width modulation voltage into an AC fifth-order pulse width modulation voltage, and generating a sine wave current in phase with the voltage of the commercial power system (8) for injection Mains system (8). While the present invention has been disclosed in its preferred embodiments, the present invention is not intended to limit the invention, and the invention may be variously modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application. [Illustration of the drawing] [0005] 100119312 The first picture (A) is a conventional single-phase diode clamp type third-order power converter. The first picture (B) is a conventional single-phase flywheel capacitive three-stage power converter.

Form No. A0101 帛20 pages/total 34 S 201251295 - Figure (c) is a conventional single-phase series bridge type third-order power converter. The second figure is a third embodiment of the preferred embodiment of the fifth-order power converter of the present invention ( a) Embodiment 1 of the filter of the present invention, FIG. 3(b) is a second embodiment of the filter of the present invention, and FIG. 4(a) to FIG. 4(d) are the fifth-order power converter. Circuit Operation of Four Switching Modes During Positive Half Cycle of Mains System Voltage [0006] Ο 100119312 Figure 5 (a) to Figure 5 (d) show the fifth-order power converter at the negative half cycle of the mains system voltage. Circuit Operation of Switching Modes FIG. 6 is a control block diagram of a preferred embodiment of the controller of the present invention. [Main component symbol description] (A) Fifth-order power converter (1) Input terminal group (2) Double buck Power converter (21) upper buck converter (211) first input (212) first output (213) first power electronic switch (214) first diode (215) first capacitor (22 Down Converter (221) Second Input (222) Second Output (223) Second Power Electronic Switch (224) Second Diode (225 ) Second Capacitor (23) First Endpoint Form No. A0101 Page 21 of 34 1002032613-0 201251295 (3) Bridge Power Converter (31) First Bridge Arm (311) Third Power Electronic Switch (312) The fourth power electronic switch (313) the first wire (32) the second bridge arm (321) the fifth power electronic switch (322) the sixth power electronic switch (323) the second wire (33) the first contact (34) ) 2nd contact (4) Filter (41) Inductor (42) Filter capacitor (5) Output end group (6) Controller (61) Adder (62) First subtractor (63) Proportional integral control (64) Signal Generator (65) Multiplier (66) Second Subtractor (67) Current Controller (68) Pulse Width Modulation Circuit (69) Third Subtractor (60) Mode Selection Circuit 100119312 Form Number A0101 Page 22 of 34 1002032613-0 201251295 (6a) First voltage detector (6b) Second voltage detector (6c) Third voltage detector (6d) Current detector (6e) comparison (7) DC power supply (8) Mains system

100119312 Form No. A0101 Page 23 of 34 1002032613-0

Claims (1)

201251295 VII. Patent application scope: A type of fifth-order power converter, including: an input terminal group: providing electrical connection to the DC power supply; a dual step-down power converter, including: an upper buck converter: a first input end and a first output end are disposed, and the first input end is electrically connected to the input end point group; the buck converter is provided with a second input end and a second output end, the second The input terminal is electrically connected to the input terminal group, and the step-down converter is electrically connected to the upper buck converter; a bridge power converter: respectively, the first output end of the dual buck power converter And the second output end is electrically connected; a filter: electrically connected to the bridge power converter; an output end group: electrically connected to the filter to provide a system with a mains Parallel; a controller: electrically connecting the dual buck power converter and the bridge power converter, respectively, providing control of the dual buck power converter to generate a DC three-order pulse width modulation voltage to supply the bridge Power conversion And controlling the bridge power converter to perform low frequency switching in synchronization with the voltage of the mains system, further converting the DC third-order pulse width modulation voltage into an AC fifth-order pulse width modulation voltage, and generating a phase in phase with the mains voltage The sinusoidal current is supplied to the mains system. 2. The fifth-order power converter of claim 1, wherein the upper buck converter is electrically coupled to the step-down converter to generate a first terminal, the upper buck converter comprising : a first power electronic switch: electrically connected to the first input end and the 100119119 form number A0101 page 24 / total 34 page 1002032613-0 201251295 - output; a first-diode: cathode electrical connection The first output terminal is electrically connected to the first end point; the first capacitor is electrically connected to the first input end and the first end point respectively. a power electronic switch: electrically connecting the second input end and the second output end respectively; a second diode: the anode is electrically connected to the second output end, and the cathode is electrically connected to the first end point; a second capacitor: electrically connected to the first: the input end and the first end point. The fifth-order power converter according to claim 1, wherein the bridge power converter includes a first a bridge arm and a second bridge arm, the first bridge arm connected in parallel The second bridge arm defines a first contact and a second contact. The first contact and the second contact are electrically connected to the first output end and the second output end respectively. The bridge arm includes a third power electronic switch and a fourth power electronic switch. The third power electronic switch is electrically connected to the fourth power electronic switch by a first wire; the second bridge arm includes a fifth power electronic switch. And a sixth power electronic switch, the fifth power electronic switch is electrically connected to the sixth power electronic switch by a second wire, and the filter is electrically connected to the first wire and the second wire, respectively. The fifth-order power converter as described in claim 1, wherein the controller is electrically connected to the first to sixth power electronic switches, respectively. The fifth-order power converter according to claim 1, wherein the controller comprises: 100119312 Form No. A010I 苐 25 pages/ Total 34 pages 1002032613-0 201251295 A first voltage detector: electrically connected The first capacitor is configured to detect a voltage value thereof to obtain a first voltage signal; and a second voltage detector is electrically connected to the second capacitor to provide a voltage value for detecting the second voltage signal. An adder: electrically connecting the first and second voltage detectors respectively, receiving and receiving the first and second voltage signals to obtain a third voltage signal; and a first subtractor: Electrically connecting the adder, receiving the third voltage signal and subtracting from a predetermined voltage signal to obtain a fourth voltage signal 9 a proportional integral controller electrically connecting the first subtractor to provide reception The fourth voltage signal generates an amplitude signal of a reference current; a third voltage detector is electrically connected to the mains system to provide a detected voltage to obtain a mains signal; a signal a generator: electrically connected to the third voltage detector, and providing the mains voltage signal to generate a unit sine wave signal in phase with the voltage of the mains system; a multiplier: electrically connecting the proportional integral controller And the signal generator is configured to receive the amplitude signal of the reference current and the unit sine wave signal and multiply to generate a reference current signal; and a current detector: electrically connecting the output end group to provide inspection An output current of the fifth-order power converter is obtained to obtain an output current signal; a second subtractor is electrically connected to the multiplier and the current detector, respectively, for receiving the reference current signal and the output current signal Performing subtraction to obtain an error signal; a current controller: electrically connecting the second subtractor to receive the error 100119312 Form No. A0101 Page 26 / Total 34 Page 1002032613-0 201251295 Signal for current closed loop Controlling to obtain a control signal; a pulse width modulation circuit: electrically connecting the current controller, providing receiving the control signal And converting the signal into a pulse width modulation signal; a third subtractor: electrically connecting the first and second voltage detectors respectively, receiving the first and second voltage signals and performing subtraction, thereby obtaining a voltage difference signal; a mode selection circuit: electrically connecting the pulse width modulation circuit and the third subtractor and the third voltage detector to generate a first driving signal and a second driving signal, and outputting Electrically connected to the first power electronic switch and the second power electronic switch to control the operation of the first and second power electronic switches respectively; a comparator: electrically connected to the third voltage detector to generate The third and fourth and fifth and sixth driving signals are electrically connected to the third to sixth power electronic switches to control the actuation of the third to sixth power electronic switches. 6. The fifth-order power converter of claim 1, wherein the filter comprises an inductor electrically connected to the output terminal group at one end and electrically connected to the other end of the bridge. Power converter. 7. The fifth-order power converter of claim 6, wherein the filter further comprises a filter capacitor in parallel with the output terminal group. 100119312 Form No. A0101 Page 27 of 34 1002032613-0