Power supply circuit of cascaded H-bridge energy storage converter and control method thereof

Abstract

The invention discloses a power supply circuit of a cascaded H-bridge energy storage converter and a control method of the power supply circuit, which are applied to a cascaded H-bridge energy storage converter system. The cascaded H-bridge energy storage converter power supply circuit comprises a first input end, a second input end, an output end, a first voltage conversion circuit, a rectification circuit, an energy storage module, a second voltage conversion circuit and a switching circuit. The power supply circuit converts electric energy of a photovoltaic cell panel and an alternating-current power grid into direct-current electric energy through a voltage conversion circuit and a rectification circuit, and two different power supply circuits, namely the photovoltaic cell panel and an energy storage module, are respectively controlled to be switched through a switching circuit so as to supply power to the direct-current side of an H-bridge module. Clean energy provided by the photovoltaic cell panel can be utilized to the maximum extent, so that dependence on a traditional power grid is reduced, and environmental protection is facilitated. Meanwhile, through reasonable power supply management, the charging and discharging times of the energy storage module can be reduced, the service life of the energy storage module is prolonged, and the reliability and economical efficiency of the whole system are improved.

Description

Technical Field

[0001] The invention relates to a power supply circuit of a cascaded H-bridge energy storage converter and a control method thereof, and belongs to the field of power electronic converters and the technical field of power supply circuits. Background Art

[0002] The cascade H-bridge energy storage converter is a highly efficient power conversion and storage device, which is usually composed of multiple H-bridge modules to provide higher output voltage and power capabilities. It is usually used in DC power systems such as photovoltaic panels, wind turbines and battery energy storage modules, providing an efficient and reliable solution for the conversion of DC to AC needs.

[0003] like Figure 1 As shown, in the case of sufficient sunlight during the day, the DC voltage conversion circuit 21 on the DC side of the H-bridge module 30 converts the DC high voltage generated by the photovoltaic panel 10 into an operating voltage suitable for the H-bridge module 30, so that the H-bridge module can work normally. In the case of no light or insufficient light at night, the photovoltaic panel 10 cannot work normally, and therefore cannot supply power for the normal operation of the H-bridge module 30. At this time, the energy storage module (such as a lithium-ion battery string or a supercapacitor) 22 supplies power to the DC side of the H-bridge module 30 to maintain the normal operation of the H-bridge module 30.

[0004] However, when the light intensity is insufficient for a long time, the electricity stored in the energy storage module cannot meet the long-term safe and stable operation of the H-bridge module. In addition, the working time of photovoltaic panels is generally long (20-30 years), while the energy storage module has a short service life due to frequent charging and discharging, making it difficult to ensure the long-term use of the H-bridge module. Summary of the invention

[0005] Purpose of the invention: In view of the problems and deficiencies in the prior art, the present invention provides a power supply circuit and control method of a cascaded H-bridge energy storage converter, which is applied to a cascaded H-bridge energy storage converter system. The cascaded H-bridge energy storage converter system is composed of n H-bridge modules connected in series, an LC filter circuit and a load (or power grid). It is used to maximize the use of clean energy provided by photovoltaic panels, thereby reducing dependence on traditional power grids and is beneficial to environmental protection. At the same time, through reasonable power supply management, the number of charge and discharge times of the energy storage module can be reduced, its service life can be extended, and the reliability and economy of the entire system can be improved.

[0006] Technical solution: A power supply circuit of a cascaded H-bridge energy storage converter, comprising: a first input terminal, a second input terminal, an output terminal, a first voltage conversion circuit, a rectifier circuit, an energy storage module, a second voltage conversion circuit and a switching circuit. The input terminal of the first voltage conversion circuit serves as the first input terminal of the cascaded H-bridge energy storage converter power supply circuit, and the first input terminal of the cascaded H-bridge energy storage converter power supply circuit is used to connect the output terminal of the photovoltaic panel.

[0007] The input end of the rectifier circuit serves as the second input end of the cascaded H-bridge energy storage converter power supply circuit, and the second input end of the cascaded H-bridge energy storage converter power supply circuit is used to connect at least one phase of AC power of the AC power grid; the output end of the rectifier circuit is connected to the input end of the energy storage module; the output end of the energy storage module is connected to the input end of the second voltage conversion circuit; the input end of the switching circuit is electrically connected to the output end of the first voltage conversion circuit and the output end of the second voltage conversion circuit respectively; the output end of the switching circuit serves as the output end of the cascaded H-bridge energy storage converter power supply circuit, and the output end of the cascaded H-bridge energy storage converter power supply circuit is used to connect the DC side of the H-bridge module.

[0008] The switching circuit controls the photovoltaic panel power supply circuit and the energy storage module power supply circuit to switch respectively, so that the photovoltaic panel and the energy storage module switch to supply power to the DC side of the H-bridge module. The first voltage conversion circuit is used to convert the DC high voltage output by the photovoltaic panel into the working voltage of the DC side of the H-bridge module; the rectifier circuit is used to convert the AC voltage of at least one phase of the AC power grid into a DC voltage and transmit it to the energy storage module; the second voltage conversion circuit is used to convert the DC high voltage output by the energy storage module into the working voltage of the DC side of the H-bridge module.

[0009] Optionally, the first voltage conversion circuit is a DC / DC conversion circuit, and the input end of the DC / DC conversion circuit serves as the input end of the first voltage conversion circuit and is used to connect to the output end of the photovoltaic panel; the output end of the DC / DC conversion circuit serves as the output end of the first voltage conversion circuit and is electrically connected to the input end of the switching circuit.

[0010] Optionally, the rectifier circuit is an uncontrolled full-bridge rectifier circuit.

[0011] Optionally, the rectifier circuit includes a positive output terminal, a negative output terminal, a first diode, a second diode, a third diode and a fourth diode; the anode of the first diode is connected to one end of at least one phase of the AC power grid, and the cathode of the first diode is the positive output terminal of the rectifier circuit; the cathode of the fourth diode is connected to the cathode of the first diode, and the anode of the fourth diode is connected to the other end of at least one phase of the AC power grid; the cathode of the third diode is connected to the anode of the fourth diode, and the anode of the third diode is the negative output terminal of the rectifier circuit; the cathode of the second diode is connected to the anode of the first diode, and the anode of the second diode is connected to the anode of the third diode.

[0012] Optionally, a third resistor is connected in series to the positive output terminal of the rectifier circuit, and a fourth resistor is connected in series to the negative output terminal of the rectifier circuit. The third resistor and the fourth resistor play a role of current limiting.

[0013] Optionally, the energy storage module is a lithium-ion battery string or a supercapacitor, which has the characteristics of high voltage and large capacity, and meets the requirements of the DC side power supply of the H-bridge module.

[0014] Optionally, the second voltage conversion circuit is a resistor voltage divider circuit, which has a simple structure and low cost. Optionally, the second voltage conversion circuit includes a first resistor and a second resistor, the first end of the first resistor and the second end of the second resistor are electrically connected to the output end of the energy storage module as the input end of the second voltage conversion circuit, and the second end of the first resistor is connected to the first end of the second resistor; wherein the first end and the second end of the second resistor are electrically connected to the input end of the switching circuit as the output end of the second voltage conversion circuit.

[0015] Optionally, the switching circuit includes a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; the first switch tube and the second switch tube have the same switching state, the third switch tube and the fourth switch tube have the same switching state, the first switch tube and the third switch tube have opposite switching states, and the second switch tube and the third switch tube have opposite switching states; the first switch tube and the second switch tube act synchronously, and the third switch tube and the fourth switch tube act synchronously.

[0016] Optionally, the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube are electromagnetic relays or insulated gate bipolar transistors or metal-oxide semiconductor field effect transistors.

[0017] Optionally, the first end of the first switch tube, the first end of the second switch tube, the first end of the third switch tube and the first end of the fourth switch tube together constitute four input ends of the switching circuit; wherein, the output end of the first voltage conversion circuit is electrically connected to the first end of the first switch tube and the first end of the second switch tube, and is used to control the conduction or disconnection of the photovoltaic panel power supply circuit; the output end of the second voltage conversion circuit is electrically connected to the first end of the third switch tube and the first end of the fourth switch tube, and is used to control the conduction or disconnection of the energy storage module power supply circuit; the second end of the first switch tube and the second end of the third switch tube are connected together, and the second end of the second switch tube and the second end of the fourth switch tube are connected together; the endpoint formed by the second end of the first switch tube and the second end of the third switch tube are connected together and the endpoint formed by the second end of the second switch tube and the second end of the fourth switch tube are electrically connected to the DC side of the H-bridge module as the two ends of the output end of the switching circuit.

[0018] A control method for a cascaded H-bridge energy storage converter power supply circuit, comprising: Set the voltage detection threshold of the photovoltaic panel power supply circuit. When the voltage of the photovoltaic panel power supply circuit is greater than the photovoltaic panel power supply circuit voltage detection threshold, the switching circuit turns on the photovoltaic panel power supply circuit to supply power to the DC side of the H-bridge module; When the photovoltaic panel power supply circuit voltage is less than the photovoltaic panel power supply circuit voltage detection threshold, the switching circuit turns on the energy storage module power supply circuit to supply power to the H-bridge module DC side.

[0019] The method further comprises: Set the minimum and maximum charging thresholds for the energy storage module. When the voltage of the energy storage module is lower than the set minimum charging threshold, the grid starts charging the energy storage module; When the voltage of the energy storage module reaches the set maximum charging threshold, the grid stops charging the energy storage module.

[0020] A cascaded H-bridge energy storage converter comprises a cascaded H-bridge energy storage converter power supply circuit and an H-bridge module. The cascaded H-bridge energy storage converter comprises n H-bridge modules, where n is a positive integer greater than 1. The n H-bridge modules are cascaded together, and the output ends are connected to a load or a power grid via a filter circuit. A first input end of the cascaded H-bridge energy storage converter power supply circuit is connected to an output end of a photovoltaic panel. A second input end of the cascaded H-bridge energy storage converter power supply circuit is connected to at least one phase of AC power in an AC power grid. An output end of the cascaded H-bridge energy storage converter power supply circuit is electrically connected to a DC side of the H-bridge module, wherein the output end of the cascaded H-bridge energy storage converter power supply circuit is used as a power supply end to supply power to a DC side of the H-bridge module with electricity emitted by the photovoltaic panel or the energy storage module.

[0021] Each cascaded H-bridge energy storage converter power supply circuit and H-bridge module also includes: a comparator and a controller, one input end of the comparator is connected to the output end of the photovoltaic panel, the other input end of the comparator is connected to the set voltage detection threshold, and the output end of the comparator is connected to the controller; the controller is electrically connected to the switching circuit, and the controller sends a control signal to control the switching circuit action according to the feedback voltage signal; at the same time, the controller also controls the charging and discharging of the energy storage module.

[0022] The photovoltaic panel power supply circuit voltage detection threshold and the photovoltaic panel power supply circuit voltage mentioned above are compared by a comparator, and the compared voltage signal is transmitted to the controller for control.

[0023] The cascaded H-bridge energy storage converter power supply circuit provided in the embodiment of the present application, when there is sufficient sunlight to make the photovoltaic panel work normally, the first voltage conversion circuit converts the DC high voltage output by the photovoltaic panel into an operating voltage suitable for the H-bridge module to power the cascaded H-bridge energy storage converter. When the light is insufficient or the photovoltaic panel works normally at night, the power supply requirement is not met, and the energy storage module is turned to power the DC side of the H-bridge module, and the second voltage conversion circuit converts the DC high voltage output by the energy storage module into an operating voltage suitable for the H-bridge module to power the cascaded H-bridge energy storage converter. The photovoltaic panel and the energy storage module are alternately powered, which reduces the charge and discharge frequency of the energy storage module, thereby increasing the service life of the energy storage module in the cascaded H-bridge energy storage converter.

[0024] Beneficial effect: The cascaded H-bridge energy storage converter power supply circuit and control method provided by the present invention are optimized for a composite system powered by photovoltaic panels and AC power grids. This system converts the electric energy of photovoltaic panels and AC power grids into DC power through a voltage conversion circuit and a rectifier circuit, and controls the switching of two different power supply modes through a switching circuit to power the H-bridge module, namely, the photovoltaic panel power supply mode and the energy storage module power supply mode. The advantage of this design is that it can maximize the use of clean energy provided by photovoltaic panels, thereby reducing dependence on traditional power grids and is beneficial to environmental protection. At the same time, through reasonable power supply management, the number of charge and discharge times of the energy storage module can be reduced, its service life can be extended, and the reliability and economy of the entire system can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an H-bridge module circuit in the prior art; Figure 2 A schematic diagram of a cascaded H-bridge energy storage converter power supply circuit provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of a cascaded H-bridge energy storage converter provided in an embodiment of the present application; Figure 4 A schematic diagram of an H-bridge module cascade structure provided in an embodiment of the present application; Figure 5 A schematic diagram of a first voltage conversion circuit structure provided in an embodiment of the present application; Figure 6 A schematic diagram of the structure of a rectifier circuit and a second voltage conversion circuit provided in an embodiment of the present application; Figure 7 A schematic diagram of a switching circuit and an H-bridge module structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0027] The present application provides a cascaded H-bridge energy storage converter, such as Figure 3 As shown, the cascaded H-bridge energy storage converter includes n H-bridge modules cascaded together, the output end of the converter is connected to the load or the power grid through a filter circuit, and the DC side of each H-bridge module is connected as follows Figure 2 The cascaded H-bridge energy storage converter power supply circuit 60 is shown.

[0028] H-bridge module cascade structure Figure 4 As shown, each H-bridge includes four power switch tubes IGBT; the four power switch tubes IGBT of the i-th H-bridge module are S i1 , S i2 , S i3 , S i4 The H-bridge module DC side is connected as follows Figure 2 The cascaded H-bridge energy storage converter power supply circuit 60 shown in FIG. i1 The collector of the i2 The emitter of S is connected to the output end of the cascaded H-bridge energy storage converter power supply circuit 60. i1 The emitter and S i2 The collector of S i3 The emitter and S i4 The collector of S i3 The collector and S i1 The collector of S i2 The emitter and S i4 The emitter of the first H-bridge module S 11 The emitter of the nth H-bridge module is connected to the filter inductor L, and the other end of the filter inductor is connected to one end of the load. n4 The emitter of is connected to the other end of the load.i3 The emitter and S i+11 The emitter connection of the H-bridge modules is realized by cascading.

[0029] The first input end of the cascaded H-bridge energy storage converter power supply circuit 60 is connected to the output end of the photovoltaic panel 40. The second input end of the cascaded H-bridge energy storage converter power supply circuit 60 is connected to at least one phase of the AC power grid 50. The output end of the cascaded H-bridge energy storage converter power supply circuit 60 is connected to the DC side of the H-bridge module 70.

[0030] Specifically, Figure 2 As shown, the cascaded H-bridge energy storage converter power supply circuit 60 includes: a first input terminal IN1, a second input terminal IN2, an output terminal OUT, a first voltage conversion circuit 61, a rectifier circuit 62, an energy storage module 63, a second voltage conversion circuit 64, and a switching circuit 65.

[0031] The input terminal IN1 of the first voltage conversion circuit 61 serves as the first input terminal IN1 of the cascaded H-bridge energy storage converter power supply circuit 60 , and the first input terminal IN1 of the cascaded H-bridge energy storage converter power supply circuit 60 is used to connect the output terminal of the photovoltaic panel 40 .

[0032] The input terminal IN2 of the rectifier circuit 62 serves as the second input terminal IN2 of the cascaded H-bridge energy storage converter power supply circuit 60, and the second input terminal IN2 of the cascaded H-bridge energy storage converter power supply circuit 60 is used to connect at least one phase of the AC power of the AC power grid 50; the output terminal of the rectifier circuit 62 is connected to the input terminal of the energy storage module 63; the output terminal of the energy storage module 63 is connected to the input terminal of the second voltage conversion circuit 64. The input terminal of the switching circuit 65 is electrically connected to the output terminal of the first voltage conversion circuit 61 and the output terminal of the second voltage conversion circuit 64 respectively; the output terminal OUT of the switching circuit 65 serves as the output terminal OUT of the cascaded H-bridge energy storage converter power supply circuit 60, and the output terminal OUT of the cascaded H-bridge energy storage converter power supply circuit 60 is used to connect the DC side of the H-bridge module 70; the switching circuit 65 controls the photovoltaic panel 40 power supply circuit and the energy storage module 63 power supply circuit to switch, so that the photovoltaic panel 40 and the energy storage module 63 switch to supply power to the DC side of the H-bridge module.

[0033] The specific working principle of the circuit is as follows: when the photovoltaic panel 40 works normally during the day or when there is sufficient sunlight, the first voltage conversion circuit 61 converts the DC high voltage output by the photovoltaic panel 40 into a working voltage suitable for the H-bridge module 70 to power the cascaded H-bridge energy storage converter. When the light is insufficient or the photovoltaic panel 40 works normally at night, the power supply requirement is not met, and the energy storage module 63 is used to power the DC side of the H-bridge module 70, and the second voltage conversion circuit 64 converts the DC high voltage output by the energy storage module 63 into a working voltage suitable for the H-bridge module 70 to power the cascaded H-bridge energy storage converter. The photovoltaic panel 40 and the energy storage module 63 are alternately powered, which reduces the charge and discharge frequency of the energy storage module 63, thereby effectively improving the service life of the energy storage module 63 in the cascaded H-bridge energy storage converter.

[0034] When the electric energy of the energy storage module 63 is low, the energy storage module 63 is charged by the AC power grid 50 via the rectifier circuit 62 .

[0035] Specifically, the first voltage conversion circuit 61 can be a DC / DC conversion circuit 611, and the input end of the DC / DC conversion circuit 611 is connected to the output end of the photovoltaic panel 40 as the input end IN1 of the first voltage conversion circuit 61; the output end of the DC / DC conversion circuit 611 is electrically connected to the input end of the switching circuit 65 as the output end of the first voltage conversion circuit 61. A DC / DC conversion circuit is an electronic circuit used to convert a DC voltage into another DC voltage. It has high-efficiency conversion capability, can reduce energy loss, and can provide a stable output voltage to adapt to load changes. In this embodiment, the DC / DC conversion circuit 611 can be used to effectively convert the DC high voltage output by the photovoltaic panel 40 into a more stable working voltage to power the H-bridge module 70.

[0036] More specifically, the DC / DC conversion circuit 611 also includes a positive input terminal, a negative input terminal, a positive output terminal, and a negative output terminal.

[0037] Specifically, the energy storage module 63 may be a lithium-ion battery string or a supercapacitor, which has high voltage and large capacity characteristics and meets the DC side power supply requirements of the H-bridge module.

[0038] More specifically, the energy storage module 63 further includes a positive input terminal, a negative input terminal, a positive output terminal, and a negative output terminal.

[0039] Specifically, the rectifier circuit 62 can be an uncontrolled full-bridge rectifier circuit. Compared with the half-bridge rectifier circuit, the full-bridge rectifier circuit can reduce the harmonic components in the current waveform, which helps to reduce electromagnetic interference. The second voltage conversion circuit 64 can be a resistor voltage divider circuit. The resistor voltage divider circuit is simple to implement and can reduce the cost of the voltage conversion circuit.

[0040] More specifically, a third resistor R3 is connected in series to the positive output terminal of the rectifier circuit 62, and a fourth resistor R4 is connected in series to the negative output terminal of the rectifier circuit 62. The third resistor R3 and the fourth resistor R4 play a role of current limiting.

[0041] For example, Figure 6 As shown, a specific implementation of the rectifier circuit and the second voltage conversion circuit provided by the present application is shown. In this implementation, the rectifier circuit 62 is an uncontrolled full-bridge rectifier circuit, and the input end of the rectifier circuit 62 is connected to a single phase of the AC power grid.

[0042] The rectifier circuit 62 includes a positive output terminal L, a negative output terminal N, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a third resistor R3, and a fourth resistor R4. The positive electrode of the first diode D1 is connected to one end of at least one phase of the AC power grid 50, the negative electrode of the first diode D1 serves as the positive output terminal L of the rectifier circuit 62, the cathode of the fourth diode D4 is connected to the cathode of the first diode D1, the anode of the fourth diode D4 is connected to the other end of at least one phase of the AC power grid 50, the cathode of the third diode D3 is connected to the anode of the fourth diode D4, the anode of the third diode D3 serves as the negative output terminal N of the rectifier circuit 62, the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode of the second diode D2 is connected to the anode of the third diode D3. The third resistor R3 is connected in series to the positive output terminal L of the rectifier circuit 62, and the fourth resistor R4 is connected in series to the negative output terminal N of the rectifier circuit 62. The positive output terminal L of the rectifier circuit 62 is connected to the positive input terminal of the energy storage module 63 via the third resistor R3, and the negative output terminal N of the rectifier circuit 62 is connected to the negative input terminal of the energy storage module 63 via the fourth resistor R4, so that the AC power of the AC power grid 50 is converted into a DC voltage through the rectifier circuit 62 to charge the energy storage module 63.

[0043] The second voltage conversion circuit 64 includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the positive output end of the energy storage module 63, the second end of the first resistor R1 is connected to the first end of the second resistor R2, and the second end of the second resistor R2 is connected to the negative output end of the energy storage module 63. The first resistor and the second resistor perform voltage conversion on the DC voltage output by the energy storage module 63 by means of resistance voltage division, so that the voltage output to the H-bridge module 70 is the working voltage.

[0044] Specifically, the switching circuit 65 includes a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube. The first switch tube and the second switch tube have the same switching state, the third switch tube and the fourth switch tube have the same switching state, the first switch tube and the third switch tube have opposite switching states, and the second diode and the fourth diode have opposite switching states; the first switch tube and the second switch tube act synchronously, and the third switch tube and the fourth switch tube act synchronously.

[0045] Specifically, the first switch tube, the second switch tube, the third switch tube, and the fourth switch tube may be electromagnetic relays, insulated gate bipolar transistors, or metal-oxide semiconductor field effect transistors.

[0046] For example, Figure 7 As shown, a specific implementation of the switching circuit provided by the present application is shown.

[0047] The switching circuit 65 includes a first switch tube K1, a second switch tube K2, a third switch tube K3, and a fourth switch tube K4. The first end of the first switch tube K1, the first end of the second switch tube K2, the first end of the third switch tube K3, and the first end of the fourth switch tube K4 together constitute four input ends of the switching circuit 65; the first end of the first switch tube K1 is connected to the positive output end of the DC / DC conversion circuit 611, the first end of the second switch tube K2 is connected to the negative output end of the DC / DC conversion circuit 611, and the first switch tube K1 and the second switch tube K2 are used to control the conduction or shutdown of the photovoltaic panel 40; the first end of the third switch tube K3 is connected to the positive output end of the energy storage module 63, the first end of the fourth switch tube K4 is connected to the negative output end of the energy storage module 63, and the third switch tube and the fourth switch tube are used to control the conduction and shutdown of the power supply circuit of the energy storage module 63. The second end of the first switch tube K1 and the second end of the third switch tube K3 are connected together, and the second end of the second switch tube K2 and the second end of the fourth switch tube K4 are connected together; the endpoint formed by the second end of the first switch tube K1 and the second end of the third switch tube K3 and the endpoint formed by the second end of the second switch tube K2 and the second end of the fourth switch tube K4 are connected together as the two ends of the output end of the switching circuit 65 and are electrically connected to the DC side of the H-bridge module 70. The switching circuit 65 controls the conduction and shutdown of the photovoltaic panel 40 and the energy storage module 63 respectively, which can realize the uninterrupted power supply of the H-bridge module 70 and ensure the stability of the system.

[0048] In addition, an embodiment of the present application provides a control method, which is applied to the cascaded H-bridge energy storage converter power supply circuit of the embodiment of the present application.

[0049] Specifically, the voltage detection threshold of the photovoltaic panel power supply circuit is set. When the voltage of the photovoltaic panel power supply circuit is greater than the voltage detection threshold, the switching circuit turns on the photovoltaic panel power supply circuit to supply power to the DC side of the H-bridge module; When the voltage of the photovoltaic panel power supply circuit is less than the voltage detection threshold, the switching circuit turns on the energy storage module power supply circuit to supply power to the DC side of the H-bridge module.

[0050] The method also includes: Set the minimum and maximum charging thresholds for the energy storage module. When the voltage of the energy storage module is lower than the set minimum charging threshold, the grid starts charging the energy storage module; When the voltage of the energy storage module reaches the set maximum charging threshold, the grid stops charging the energy storage module.

[0051] The present application also relates to a cascaded H-bridge energy storage converter, including the cascaded H-bridge energy storage converter power supply circuit as described above and a control method for the cascaded H-bridge energy storage converter power supply circuit as described in any embodiment thereof, and an H-bridge module, the cascaded H-bridge energy storage converter includes n H-bridge modules (n is a positive integer greater than 1), the n H-bridge modules are cascaded together, and the output end is connected to a load or a power grid through a filtering circuit; the first input end of the cascaded H-bridge energy storage converter power supply circuit is connected to the output end of a photovoltaic panel; the second input end of the cascaded H-bridge energy storage converter power supply circuit is connected to at least one phase of AC power in an AC power grid; the output end of the cascaded H-bridge energy storage converter power supply circuit is electrically connected to the DC side of the H-bridge module, wherein the output end of the cascaded H-bridge energy storage converter power supply circuit is used as a power supply end to supply power to the DC side of the H-bridge module with electricity emitted by the photovoltaic panel or the energy storage module.

[0052] Each cascaded H-bridge energy storage converter power supply circuit and H-bridge module also includes: a comparator, a controller, one input end of the comparator is connected to the output end of the photovoltaic panel, one output end of the comparator is connected to the set voltage detection threshold, and the other output end of the comparator is connected to the controller; the controller is electrically connected to the switching circuit, and the controller sends a control signal to control the switching circuit action according to the feedback detection signal, the voltage of the photovoltaic panel power supply circuit and the set photovoltaic panel power supply circuit voltage detection threshold after comparison by the comparator; at the same time, the controller also controls the charging and discharging of the energy storage module. The controller controls the switching circuit action according to the voltage signal fed back by the comparator, which is used to control the switching circuit to turn on or off the photovoltaic panel power supply circuit or the energy storage module power supply circuit.

[0053] The cascaded H-bridge energy storage converter power supply circuit provided in the embodiment of the present application, when there is sufficient sunlight to make the photovoltaic panel work normally, the first voltage conversion circuit converts the DC high voltage output by the photovoltaic panel into an operating voltage suitable for the H-bridge module to power the cascaded H-bridge energy storage converter. When the light is insufficient or the photovoltaic panel works normally at night, the power supply requirement is not met, and the energy storage module is turned to power the DC side of the H-bridge module, and the second voltage conversion circuit converts the DC high voltage output by the energy storage module into an operating voltage suitable for the H-bridge module to power the cascaded H-bridge energy storage converter. The photovoltaic panel and the energy storage module are alternately powered, which reduces the charge and discharge frequency of the energy storage module, thereby increasing the service life of the energy storage module in the cascaded H-bridge energy storage converter.

Claims

1. A power supply circuit for a cascaded H-bridge energy storage converter, characterized in that: include: A first input terminal, a second input terminal, an output terminal, a first voltage conversion circuit, a rectification circuit, an energy storage module, a second voltage conversion circuit and a switching circuit; Wherein, the input end of the first voltage conversion circuit serves as the first input end of the cascaded H-bridge energy storage converter power supply circuit, and the first input end of the cascaded H-bridge energy storage converter power supply circuit is used to connect the output end of the photovoltaic panel; The input end of the rectifier circuit serves as the second input end of the cascaded H-bridge energy storage converter power supply circuit, and the second input end of the cascaded H-bridge energy storage converter power supply circuit is used to connect at least one phase of AC power of the AC power grid; the output end of the rectifier circuit is connected to the input end of the energy storage module; the output end of the energy storage module is connected to the input end of the second voltage conversion circuit; The input end of the switching circuit is electrically connected to the output end of the first voltage conversion circuit and the output end of the second voltage conversion circuit respectively; the output end of the switching circuit serves as the output end of the cascaded H-bridge energy storage converter power supply circuit, and the output end of the cascaded H-bridge energy storage converter power supply circuit is used to connect the DC side of the H-bridge module; The switching circuit controls the photovoltaic panel power supply circuit and the energy storage module power supply circuit to switch respectively, so that the photovoltaic panel and the energy storage module switch to supply power to the DC side of the H-bridge module. The first voltage conversion circuit is used to convert the DC high voltage output by the photovoltaic panel into the working voltage of the DC side of the H-bridge module; the rectifier circuit is used to convert the AC voltage of at least one phase of the AC power grid into a DC voltage and transmit it to the energy storage module; the second voltage conversion circuit is used to convert the DC high voltage output by the energy storage module into the working voltage of the DC side of the H-bridge module.

2. The power supply circuit of the cascaded H-bridge energy storage converter according to claim 1, characterized in that: The first voltage conversion circuit is a DC / DC conversion circuit, and the input end of the DC / DC conversion circuit is used as the input end of the first voltage conversion circuit to connect to the output end of the photovoltaic panel; the output end of the DC / DC conversion circuit is used as the output end of the first voltage conversion circuit to be electrically connected to the input end of the switching circuit.

3. The power supply circuit of the cascaded H-bridge energy storage converter according to claim 1, characterized in that: The rectifier circuit includes a positive output terminal, a negative output terminal, a first diode, a second diode, a third diode and a fourth diode; the anode of the first diode is connected to one end of at least one phase of the alternating current of the alternating current grid, and the cathode of the first diode is the positive output terminal of the rectifier circuit; the cathode of the fourth diode is connected to the cathode of the first diode, and the anode of the fourth diode is connected to the other end of at least one phase of the alternating current of the alternating current grid; the cathode of the third diode is connected to the anode of the fourth diode, and the anode of the third diode is the negative output terminal of the rectifier circuit; the cathode of the second diode is connected to the anode of the first diode, and the anode of the second diode is connected to the anode of the third diode.

4. The power supply circuit of the cascaded H-bridge energy storage converter according to claim 1, characterized in that: A third resistor is connected in series to the positive output end of the rectifier circuit, and a fourth resistor is connected in series to the negative output end of the rectifier circuit. The third resistor and the fourth resistor play a role of current limiting.

5. The power supply circuit of the cascaded H-bridge energy storage converter according to claim 1, characterized in that: The second voltage conversion circuit is a resistor voltage divider circuit.

6. The power supply circuit of the cascaded H-bridge energy storage converter according to claim 1, characterized in that: The second voltage conversion circuit includes a first resistor and a second resistor, wherein the first end of the first resistor and the second end of the second resistor are electrically connected to the output end of the energy storage module as the input end of the second voltage conversion circuit, and the second end of the first resistor is connected to the first end of the second resistor; wherein the first end and the second end of the second resistor are electrically connected to the input end of the switching circuit as the output end of the second voltage conversion circuit.

7. The power supply circuit of the cascaded H-bridge energy storage converter according to claim 1, characterized in that: The switching circuit comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; the first switch tube and the second switch tube have the same switching state, the third switch tube and the fourth switch tube have the same switching state, the first switch tube and the third switch tube have opposite switching states, and the second switch tube and the third switch tube have opposite switching states; the first switch tube and the second switch tube act synchronously, and the third switch tube and the fourth switch tube act synchronously; The first end of the first switch tube, the first end of the second switch tube, the first end of the third switch tube and the first end of the fourth switch tube together constitute four input ends of the switching circuit; wherein, the output end of the first voltage conversion circuit is electrically connected to the first end of the first switch tube and the first end of the second switch tube, and is used to control the conduction or disconnection of the photovoltaic panel power supply circuit; the output end of the second voltage conversion circuit is electrically connected to the first end of the third switch tube and the first end of the fourth switch tube, and is used to control the conduction or disconnection of the energy storage module power supply circuit; the second end of the first switch tube and the second end of the third switch tube are connected together, and the second end of the second switch tube and the second end of the fourth switch tube are connected together; the endpoint formed by connecting the second end of the first switch tube and the second end of the third switch tube together and the endpoint formed by connecting the second end of the second switch tube and the second end of the fourth switch tube together are electrically connected to the DC side of the H-bridge module as the two ends of the output end of the switching circuit.

8. A control method for a cascaded H-bridge energy storage converter power supply circuit according to any one of claims 1 to 7, characterized in that: include: Set the voltage detection threshold of the photovoltaic panel power supply circuit. When the voltage of the photovoltaic panel power supply circuit is greater than the voltage detection threshold, the switching circuit turns on the photovoltaic panel power supply circuit to supply power to the DC side of the H-bridge module; When the voltage of the photovoltaic panel power supply circuit is less than the voltage detection threshold, the switching circuit turns on the energy storage module power supply circuit to supply power to the DC side of the H-bridge module; Set the minimum and maximum charging thresholds for the energy storage module. When the voltage of the energy storage module is lower than the set minimum charging threshold, the grid starts charging the energy storage module; When the voltage of the energy storage module reaches the set maximum charging threshold, the grid stops charging the energy storage module.

9. A cascaded H-bridge energy storage converter, characterized in that: It includes a cascaded H-bridge energy storage converter power supply circuit and an H-bridge module. The cascaded H-bridge energy storage converter includes n H-bridge modules, where n is a positive integer greater than 1. The n H-bridge modules are cascaded together, and the output end is connected to a load or a power grid through a filter circuit; the first input end of the cascaded H-bridge energy storage converter power supply circuit is connected to the output end of a photovoltaic panel; The second input end of the cascaded H-bridge energy storage converter power supply circuit is connected to at least one phase of AC power in the AC power grid; the output end of the cascaded H-bridge energy storage converter power supply circuit is electrically connected to the DC side of the H-bridge module, wherein the output end of the cascaded H-bridge energy storage converter power supply circuit is used as a power supply end to use the electricity generated by the photovoltaic panel or the energy storage module to power the DC side of the H-bridge module.

10. The cascaded H-bridge energy storage converter according to claim 9, characterized in that: Each cascaded H-bridge energy storage converter power supply circuit and H-bridge module also includes: a comparator and a controller, one input end of the comparator is connected to the output end of the photovoltaic panel, the other input end of the comparator is connected to the set photovoltaic panel power supply circuit voltage detection threshold, and the output end of the comparator is connected to the controller; the controller is electrically connected to the switching circuit, and the controller sends a control signal to control the switching circuit action according to the feedback detection signal; at the same time, the controller also controls the charging and discharging of the energy storage module.

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