A non-isolated type electrolytic hydrogen production load characteristic test power supply of inverter stage

Abstract

The application discloses an inverter stage non-isolated type electrolytic hydrogen production load characteristic test power supply and relates to the field of electrolytic hydrogen production power supplies; the test power supply is obtained by parallel connection of a triple interlaced parallel connection boost converter and a single-phase boost converter; the input end of a single-phase half-bridge inverter is connected with the output end of the single-phase boost converter; the output end of the single-phase half-bridge inverter and the output end of the triple interlaced parallel connection boost converter are connected with an electrolytic tank; the triple interlaced parallel connection boost converter obtains a first boost voltage output direct current by boosting the voltage at the grid side; the single-phase half-bridge inverter obtains a second boost voltage output ripple current by boosting the single-phase boost converter; the electrolytic tank performs water electrolysis according to the direct current and the ripple current; the application can provide the direct current and the ripple current without using an isolation transformer, avoids the generation of circulating current, reduces power loss and cost.

Description

Technical Field

[0001] This invention relates to the field of electrolytic hydrogen production power supplies, and in particular to a non-isolated inverter-stage electrolytic hydrogen production load characteristic test power supply. Background Technology

[0002] When distributed power generation systems such as photovoltaic power generation are connected to electrolytic hydrogen production equipment through indirect coupling, that is, when a DC / DC converter is used to connect the electrolyzer and the DC bus, the converter will have a high step-down ratio due to the generally high bus voltage level in new energy hydrogen production systems. Secondly, in order to ensure the stable operation of the electrolyzer, improve the hydrogen production efficiency of the electrolyzer, extend the life of the electrolyzer, and reduce the output current ripple of the converter is also a topic that needs to be studied when applying electrolyzers.

[0003] Unlike traditional industrial hydrogen production, hydrogen production using renewable energy sources requires not only meeting hydrogen production needs but also improving power load characteristics and ensuring the safe and stable operation of the power grid. Hydrogen production systems face various complex operating conditions when participating in peak shaving and frequency regulation, placing high demands on the fluctuation adaptability of electrolytic hydrogen production systems. Therefore, it is necessary to study the operating characteristics of electrolyzers under complex conditions. Globally, there is limited research on water electrolysis for hydrogen production in high-proportion renewable energy grids, and research on the power supply for providing a testing environment for hydrogen electrolyzer loads is also lacking. Establishing a testing environment typically requires meeting the following functional requirements:

[0004] 1) Meet the normal power supply requirements of the electrolytic cell, reduce the bus voltage level, output DC current, and minimize the output of ripple current.

[0005] 2) Provides a testing environment for the fluctuation adaptability of the electrolytic cell, and can output AC ripple current with adjustable amplitude and frequency.

[0006] Currently, there have been some good research results on the working characteristics of hydrogen electrolyzers under fluctuating conditions. For example, the authors Buitendach HPC, Gouws R, Martinson CA, et al., titled "Effect of ripple current on the efficiency of a PEM electrolyzer [J]", published in Results in Engineering, studied the effect of different ripple currents on the working efficiency of PEM electrolyzers, using a programmable power supply including a signal generator to output different ripple currents. Another author, Guilbert D, N'Diaye A, Luberda P, et al., titled "Fuel cell lifespan optimization by developing a power switch fault-tolerant control in a floating interleaved boost converter [J]", published in Fuel Cells, investigated the effect of large current ripple on the lifespan and performance of PEMFCs when the DC / DC converter powering the fuel cell experiences an open-circuit fault.

[0007] However, current research focuses on modifying the power supply environment of the hydrogen production load to indirectly measure its operating characteristics under fluctuating conditions. There is a lack of a source / grid integrated test power supply module that can simultaneously provide both DC current and ripple current to the hydrogen production electrolyzer load for testing its operating characteristics. If a test power supply capable of simultaneously providing both DC current and ripple current to the hydrogen production electrolyzer load were to be built, it would inevitably involve parallel connection of converters with different current output characteristics, thus raising the issue of circulating current between the converters. Generally, adding an isolation transformer can prevent circulating current flow, but this increases losses and the cost of the test power supply. Summary of the Invention

[0008] The purpose of this invention is to provide a non-isolated inverter-stage electrolytic hydrogen production load characteristic test power supply that can provide DC current and ripple current without the need for an isolation transformer, thereby avoiding the generation of circulating current, reducing power loss and cost.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] A non-isolated inverter-stage electrolytic hydrogen production load characteristic test power supply, the test power supply comprising: a triple-interleaved parallel boost converter, a single-phase boost converter, a single-phase half-bridge inverter, and an electrolytic cell;

[0011] The triple-interleaved parallel boost converter and the single-phase boost converter are connected in parallel; the input terminals of both the triple-interleaved parallel boost converter and the single-phase boost converter are connected to the grid side; the input terminal of the single-phase half-bridge inverter is connected to the output terminal of the single-phase boost converter; the output terminals of both the single-phase half-bridge inverter and the triple-interleaved parallel boost converter are connected to the electrolytic cell.

[0012] The triple-interleaved parallel boost converter is used to boost the voltage on the grid side to obtain a first boost voltage, and output DC current according to the first boost voltage;

[0013] The single-phase half-bridge inverter is used to output ripple current based on the second boost voltage obtained by the single-phase boost converter.

[0014] The electrolytic cell is used to perform water electrolysis based on the DC current and the ripple current.

[0015] Optionally, the test power supply further includes: a rectifier module;

[0016] One end of the rectifier module is connected to the power grid side; the other end of the rectifier module is connected to the input terminal of the triple-interleaved parallel boost converter and the input terminal of the single-phase boost converter, respectively.

[0017] The rectifier module is used to filter and stabilize the initial voltage on the grid side to obtain the voltage on the grid side.

[0018] Optionally, the rectifier module includes: a step-down transformer, a first three-phase bridge diode rectifier, a second three-phase bridge diode rectifier, a first inductor, and a first capacitor;

[0019] One end of the step-down transformer is connected to the power grid side; the first three-phase bridge diode rectifier and the second three-phase bridge diode rectifier are connected in parallel; the other end of the step-down transformer is connected to the input terminals of the first three-phase bridge diode rectifier and the second three-phase bridge diode rectifier, respectively; the output terminal of the first three-phase bridge diode rectifier is connected to one end of the first inductor; the other end of the first inductor is connected to one end of the first capacitor; the other end of the first capacitor is connected to the output terminal of the second three-phase bridge diode rectifier.

[0020] Optionally, the secondary winding configuration of the step-down transformer includes a star connection and a delta connection.

[0021] Optionally, the triple-interleaved parallel boost converter includes: a combined inductor, a combined diode, a combined switch, and a second capacitor;

[0022] The combined diode is connected in parallel with the second capacitor, and the combined diode is connected in series with the combined switch transistor; the input terminal of the combined inductor is connected to the output terminal of the rectifier module; the output terminal of the combined inductor is connected to the connection terminal of the combined diode and the combined switch transistor; the second capacitor is also connected in parallel with the electrolytic cell.

[0023] Optionally, the combined inductor includes a second inductor, a third inductor, and a fourth inductor connected in parallel; the combined diode includes a first diode, a second diode, and a third diode connected in parallel; and the combined switching transistor includes a first switching transistor, a second switching transistor, and a third switching transistor connected in parallel.

[0024] The input terminals of the second inductor, the third inductor, and the fourth inductor are all connected to the output terminal of the rectifier module.

[0025] The first switching transistor is connected in series with the first diode; the second switching transistor is connected in series with the second diode; the third switching transistor is connected in series with the third diode;

[0026] The connection terminals of the third switch and the third diode are connected to the output terminal of the fourth inductor;

[0027] The connection terminals of the second switching transistor and the second diode are connected to the output terminal of the third inductor;

[0028] The connection terminals of the first switching transistor and the first diode are connected to the output terminal of the second inductor.

[0029] Optionally, the single-phase half-bridge inverter includes: a first bridge arm, a second bridge arm, and an inverter inductor;

[0030] The input terminal of the first bridge arm is connected to the positive output terminal of the single-phase boost converter; the output terminal of the second bridge arm is connected to the negative output terminal of the single-phase boost converter; the output terminal of the first bridge arm is connected to the input terminal of the second bridge arm; the input terminal of the inverter inductor is connected to the output terminals of the first bridge arm and the second bridge arm respectively; the output terminal of the inverter inductor is connected to the electrolytic cell.

[0031] Optionally, the single-phase boost converter includes: a fifth inductor, a fourth switching transistor, a fourth diode, and a third capacitor;

[0032] The input terminal of the fifth inductor is connected to the positive output terminal of the rectifier module; the output terminal of the fifth inductor is connected to the input terminal of the fourth switch and one end of the fourth diode; the other end of the fourth diode is connected to one end of the third capacitor; the other end of the third capacitor is connected to the output terminal of the fourth switch; and the output terminal of the fourth switch is also connected to the negative output terminal of the rectifier module.

[0033] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] This invention provides a non-isolated inverter-stage power supply for testing the load characteristics of hydrogen electrolysis. It outputs DC current through a triple-interleaved parallel boost converter and ripple current through a combination of a single-phase boost converter and a single-phase half-bridge inverter. The electrolyzer performs water electrolysis based on the DC current and the ripple current. The presence of the single-phase half-bridge inverter avoids the generation of circulating current, thus eliminating the need for an isolation transformer and reducing power loss and cost. Therefore, this invention can provide both DC current and ripple current without the need for an isolation transformer, avoiding circulating current and reducing power loss and cost. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a structural diagram of the inverter-stage non-isolated electrolytic hydrogen production load characteristic test power supply provided in an embodiment of the present invention;

[0037] Figure 2 The circuit topology diagram of the inverter-stage non-isolated electrolytic hydrogen production load characteristic test power supply provided in the embodiment of the present invention;

[0038] Figure 3 The circuit topology diagram of the rectifier module provided in the embodiment of the present invention;

[0039] Figure 4 The circuit topology diagram of the triple-interleaved parallel boost converter provided in the embodiment of the present invention is shown below;

[0040] Figure 5 This is a control block diagram of a triple-interleaved parallel boost converter provided in an embodiment of the present invention;

[0041] Figure 6This is a circuit topology diagram of a single-phase half-bridge inverter provided in an embodiment of the present invention;

[0042] Figure 7 This is a control block diagram of a single-phase half-bridge inverter provided in an embodiment of the present invention;

[0043] Figure 8 The circuit topology diagram of the single-phase boost converter provided in the embodiment of the present invention;

[0044] Figure 9 This is a control block diagram of the control loop of a single-phase boost converter provided in an embodiment of the present invention;

[0045] Figure 10 A schematic diagram of an equivalent model of an electrolytic cell provided in an embodiment of the present invention;

[0046] Figure 11 The diagram shows the power circuit topology of a full-bridge inverter provided in an embodiment of the present invention.

[0047] Symbol explanation:

[0048] Triple-phase interleaved parallel boost converter-1, Single-phase boost converter-2, Single-phase half-bridge inverter-3, Electrolytic cell-4, Grid side-5, Rectifier module-6, First three-phase bridge diode rectifier-7, Second three-phase bridge diode rectifier-8, Combined inductor-9, Combined diode-10, Combined switching transistor-11, Buck transformer-T1, First inductor-L1, First capacitor-C1, Second capacitor-C2, Second inductor-L2, Third inductor-L3, Fourth inductor-L4; First diode-D1, Second diode-D2, Third diode-D3; First switching transistor-S1, Second switching transistor-S2, Third switching transistor-S3, First bridge arm-P1, Second bridge arm-P2, Inverter inductor-L ac Fifth inductor - L5, Fourth switch - VT, Fourth diode - D4, Third capacitor - C3, Electrolytic cell ohm resistor - R ohm Charge transfer resistance - R act Double-layer capacitor - C dl Open circuit voltage -V rev . Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] The purpose of this invention is to provide a non-isolated inverter-stage electrolytic hydrogen production load characteristic test power supply that can provide DC current and ripple current without the need for an isolation transformer, thereby avoiding the generation of circulating current, reducing power loss and cost.

[0051] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] like Figure 1 As shown, this embodiment of the invention provides a test power supply for inverter-stage non-isolated electrolytic hydrogen production load characteristics. The test power supply includes: a triple-interleaved parallel boost converter 1, a single-phase boost converter 2, a single-phase half-bridge inverter 3, and an electrolytic cell 4.

[0053] The triple-interleaved parallel boost converter 1 and the single-phase boost converter 2 are connected in parallel; the input terminals of both the triple-interleaved parallel boost converter 1 and the single-phase boost converter 2 are connected to the grid side 5; the input terminal of the single-phase half-bridge inverter 3 is connected to the output terminal of the single-phase boost converter 2; the output terminals of both the single-phase half-bridge inverter 3 and the triple-interleaved parallel boost converter 1 are connected to the electrolytic cell 4.

[0054] The triple-interleaved parallel boost converter 1 is used to boost the voltage of the grid side 5 to obtain the first boost voltage, and output DC current according to the first boost voltage.

[0055] The single-phase half-bridge inverter 3 is used to output ripple current based on the second boost voltage obtained by the single-phase boost converter 2.

[0056] Electrolytic cell 4 is used for water electrolysis based on DC current and ripple current.

[0057] In one embodiment, the test power supply further includes a rectifier module 6.

[0058] One end of the rectifier module 6 is connected to the grid side 5; the other end of the rectifier module 6 is connected to the input terminal of the triple-interleaved parallel boost converter 1 and the input terminal of the single-phase boost converter 2, respectively.

[0059] The rectifier module 6 is used to filter and stabilize the initial voltage of the grid side 5 to obtain the voltage of the grid side.

[0060] Figure 2 This is a circuit topology diagram of a non-isolated inverter-stage electrolytic hydrogen production load characteristic test power supply provided in an embodiment of the present invention. The following describes each component of the circuit topology.

[0061] Specifically, in Figure 3In the rectifier module 6, there are: step-down transformer T1, first three-phase bridge diode rectifier 7, second three-phase bridge diode rectifier 8, first inductor L1 and first capacitor C1.

[0062] One end of the step-down transformer T1 is connected to the grid side 5; the first three-phase bridge diode rectifier 7 and the second three-phase bridge diode rectifier 8 are connected in parallel; the other end of the step-down transformer T1 is connected to the input terminals of the first three-phase bridge diode rectifier 7 and the second three-phase bridge diode rectifier 8, respectively; the output terminal of the first three-phase bridge diode rectifier 7 is connected to one end of the first inductor L1; the other end of the first inductor L1 is connected to one end of the first capacitor C1; the other end of the first capacitor C1 is connected to the output terminal of the second three-phase bridge diode rectifier 8. Figure 3 In the test power supply topology, R refers to the various components subsequently connected to the rectifier module 6, namely the triple-interleaved parallel boost converter 1, the single-phase boost converter 2, the single-phase half-bridge inverter 3, and the electrolytic cell 4.

[0063] The secondary winding configuration of the step-down transformer T1 includes both star connection and delta connection.

[0064] Specifically, the secondary windings of the step-down transformer T1 are connected in a star configuration and a delta configuration, respectively, to form two sets of voltages with a phase difference of 30 degrees and equal magnitude. These are connected to two parallel rectifier bridges, namely the first three-phase bridge diode rectifier 7 and the second three-phase bridge diode rectifier 8. By utilizing the different secondary winding connections, the phases of the two sets of three-phase AC power supplies are staggered by 30 degrees, thereby causing the output voltage to pulsate 12 times in each AC power supply cycle.

[0065] In one embodiment, such as Figure 4 As shown, the triple-interleaved parallel boost converter 1 includes: a combined inductor 9, a combined diode 10, a combined switching transistor 11, and a second capacitor C2.

[0066] The combined diode 10 is connected in parallel with the second capacitor C2, and the combined diode 10 is connected in series with the combined switch 11; the input terminal of the combined inductor 9 is connected to the output terminal of the rectifier module 6; the output terminal of the combined inductor 9 is connected to the connection terminal of the combined diode 10 and the combined switch 11; the second capacitor C2 is also connected in parallel with the electrolytic cell 4.

[0067] Specifically, the combined inductor 9 includes a second inductor L2, a third inductor L3, and a fourth inductor L4 connected in parallel; the combined diode 10 includes a first diode D1, a second diode D2, and a third diode D3 connected in parallel; and the combined switch 11 includes a first switch S1, a second switch S2, and a third switch S3 connected in parallel.

[0068] The input terminal of the second inductor L2, the input terminal of the third inductor L3 and the input terminal of the fourth inductor L4 are all connected to the output terminal of the rectification module 6.

[0069] The first switching tube S1 is connected in series with the first diode D1; the second switching tube S2 is connected in series with the second diode D2; the third switching tube S3 is connected in series with the third diode D3. The connecting end of the third switching tube S3 and the third diode D3 is connected to the output end of the fourth inductor L4. The connecting end of the second switching tube S2 and the second diode D2 is connected to the output end of the third inductor L3. The connecting end of the first switching tube S1 and the first diode D1 is connected to the output end of the second inductor L2.

[0070] The three-phase interleaved parallel boost converter 1 operates in continuous conduction mode (CCM), and the inductor current is always greater than zero throughout the entire working cycle. According to the switching states of whether the first switching tube S1, the second switching tube S2 and the third switching tube S3 are conducting, the three-phase interleaved parallel boost converter 1 has eight working states from the first state to the eighth state. First state: the first switching tube S1 is conducting, and the second switching tube S2 and the third switching tube S3 are off; Second state: the first switching tube S1 and the second switching tube S2 are conducting, and the third switching tube S3 is off; Third state: the first switching tube S1 and the third switching tube S3 are conducting, and the second switching tube S2 is off; Fourth state: the second switching tube S2 is conducting, and the first switching tube S1 and the third switching tube S3 are off; Fifth state: the second switching tube S2 and the third switching tube S3 are conducting, and the first switching tube S1 is off; Sixth state: the third switching tube S3 is conducting, and the first switching tube S1 and the second switching tube S2 are off; Seventh state: the first switching tube S1, the second switching tube S2 and the third switching tube S3 are all off; Eighth state: the first switching tube S1, the second switching tube S2 and the third switching tube S3 are all conducting. In Figure 4 , R 电 refers to the electrolyzer 4 connected to the three-phase interleaved parallel boost converter 1.

[0071] The control loop of the three-phase interleaved parallel boost (Boost) converter 1 adopts a voltage-current double-loop control method. As shown in Figure 5 , Figure 5 in the figure, v dcref is the load-side voltage, that is, the given command signal of the electrolyzer 4, PI1 is the voltage outer loop controller, and PI2 is the current inner loop controller. v d is the grid-side voltage output by the rectification module 6. The output voltage v of the three-phase interleaved parallel boost converter 1 dc undergoes moving average filtering, then is differenced with the command voltage v dcref and then input to the voltage loop PI controller, and then is differenced with the total input current i in, that is, the current output by the rectifier module 6 is subjected to difference calculation and then output by the inner current loop controller, and then after PWM control, the corresponding driving signals of the first switching tube S1, the second switching tube S2 and the third switching tube S3 are output. PWM control is a commonly used control method for DC / DC conversion circuits. In order to stabilize the output signal of the conversion circuit, the driving signal generated by the controller has a fixed frequency, and its pulse width can change with the change of the modulation signal.

[0072] In one embodiment, as Figure 6 shown, the single-phase half-bridge inverter 3 comprises: a first bridge arm P1, a second bridge arm P2 and an inverter inductor L ac .

[0073] The input terminal of the first bridge arm P1 is connected to the positive output terminal of the single-phase boost converter 2; the output terminal of the second bridge arm P2 is connected to the negative output terminal of the single-phase boost converter 2; the output terminal of the first bridge arm P1 is connected to the input terminal of the second bridge arm P2; the inverter inductor L ac has its input terminal respectively connected to the output terminal of the first bridge arm P1 and the input terminal of the second bridge arm P2; the inverter inductor L ac has its output terminal connected to the electrolytic cell 4. i ac is the current passing through the inverter inductor L ac , that is, the output ripple current.

[0074] The control block diagram of the single-phase half-bridge inverter 3 is shown in Figure 7 , the driving signal of the single-phase half-bridge inverter 3 is generated by sinusoidal pulse width modulation (SPWM), and the ripple current i ac and the deviation i from the target value acref is used as the input of the PI controller, and the output of the PI controller is used as the input signal of the PWM driving circuit. The equivalent output voltage is realized by controlling the duty cycle of the output waveform, and P1 and P2 are alternately turned on and off. Kpwm is the equivalent PWM modulation gain, v dc is the output side DC voltage feedforward, that is, the output voltage of the triple interleaved parallel boost converter 1, 1 / L acs is the filtering transfer function of the inverter inductor.

[0075] In one embodiment, as Figure 8 shown, the single-phase boost converter 2 comprises: a fifth inductor L5, a fourth switching tube VT, a fourth diode D4 and a third capacitor C3. Figure 8 herein, v d is the grid-side voltage output by the rectifier module 6, v boost is the second boosted voltage obtained by boosting through the single-phase boost converter 2. R 半 refers to the single-phase half-bridge inverter 3.

[0076] The input terminal of the fifth inductor L5 is connected to the positive output terminal of the rectifier module 6; the output terminal of the fifth inductor L5 is connected to the input terminal of the fourth switch VT and one end of the fourth diode D4; the other end of the fourth diode D4 is connected to one end of the third capacitor C3; the other end of the third capacitor C3 is connected to the output terminal of the fourth switch VT; the output terminal of the fourth switch VT is also connected to the negative output terminal of the rectifier module 6.

[0077] The single-phase boost converter 2 uses PWM control to control the switching of the fourth switching transistor VT. Its control loop block diagram is as follows: Figure 9 As shown, G cv (s), G ci (s) are the PI controller transfer functions for the outer voltage loop and the inner current loop, respectively, G m (s) is the transfer function of the modulation process, G id (s) is the transfer function of inductor current with respect to duty cycle, G vi (s) is the transfer function of output voltage to inductor current. When designing the control loop, the inner current loop is designed first, followed by the outer voltage loop. The output of the PI controller in the outer voltage loop serves as the control signal for the inner current loop. The design goal of the control loop is to make the DC output voltage, i.e., the second boost voltage, follow the given value.

[0078] The output side of the triple-interleaved parallel boost converter 1 is directly connected to the electrolytic cell 4, providing DC power to the electrolytic cell 4. The equivalent model of the electrolytic cell 4 is as follows: Figure 10 As shown in the figure, R ohm R is the ohmic resistance of the electrolytic cell. This parameter has little dependence on pressure and operating current and is assumed to be constant. act C represents the charge transfer resistance, which is the equivalent resistance of charge transfer between the electrodes during electrolysis. dl A double-layer capacitor, its physical meaning is the accumulation of charge and storage of energy on the plates of an electrolytic cell, V rev It is a reversible voltage, also known as open-circuit voltage.

[0079] The single-phase boost converter 2 boosts the DC voltage to obtain a second boosted voltage, which is then supplied to the single-phase half-bridge inverter 3. The single-phase half-bridge inverter 3 is responsible for providing controllable ripple to the electrolytic cell 4. The single-phase half-bridge inverter 3 uses a half-bridge structure to avoid circulating current. If a full-bridge structure were used, such as... Figure 11 As shown, since the voltage at point M on the voltage regulator side, the midpoint of the inverter P3 and P4 bridge arms, and the connection point N of the P4 bridge arm are the same, a circulating current will be generated between the two converters when the P2 and P3 bridge arms are turned on and the P1 and P4 bridge arms are turned off. Figure 11The solid line represents the output current flow of the inverter, and the dashed line represents the circulating current flow. Considering the functional requirements of the test power supply, namely, outputting a small AC current with controllable frequency, the P3 and P4 bridge arms that generate short-circuit loop conditions are removed, and a half-bridge structure is adopted to output AC current. The established topology is as follows. Figure 6 As shown.

[0080] The test power supply provided by this invention can simultaneously provide DC current and ripple current to the hydrogen electrolyzer, thereby testing the load operating characteristics of the hydrogen electrolyzer. The voltage and current dual closed-loop control circuit equipped in this invention for the triple-interleaved parallel boost converter 1 enables the DC output voltage to accurately follow the command value. Furthermore, the current closed-loop control circuit equipped in the single-phase boost converter 2 and the single-phase half-bridge inverter 3 enables the ripple current input to the electrolyzer 4 to quickly track the given command value.

[0081] The single-phase half-bridge inverter with a half-bridge structure used in this invention not only achieves the function of outputting controllable ripple to the hydrogen production load, but also avoids the generation of circulating current without the use of an isolation transformer, reducing losses and the overall cost of the test power supply.

[0082] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0083] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A power supply for testing the load characteristics of a non-isolated inverter-stage electrolytic hydrogen production system, characterized in that, The test power supply includes: a triple-interleaved parallel boost converter, a single-phase boost converter, a single-phase half-bridge inverter, and an electrolytic cell; The triple-interleaved parallel boost converter and the single-phase boost converter are connected in parallel; the input terminals of both the triple-interleaved parallel boost converter and the single-phase boost converter are connected to the grid side; the input terminal of the single-phase half-bridge inverter is connected to the output terminal of the single-phase boost converter; the output terminals of both the single-phase half-bridge inverter and the triple-interleaved parallel boost converter are connected to the electrolytic cell. The triple-interleaved parallel boost converter is used to boost the voltage on the grid side to obtain a first boost voltage, and output DC current according to the first boost voltage; The single-phase half-bridge inverter is used to output ripple current based on the second boost voltage obtained by the single-phase boost converter. The electrolytic cell is used to perform water electrolysis based on the DC current and the ripple current. The test power supply also includes: a rectifier module; One end of the rectifier module is connected to the power grid side; the other end of the rectifier module is connected to the input terminal of the triple-interleaved parallel boost converter and the input terminal of the single-phase boost converter, respectively. The rectifier module is used to filter and stabilize the initial voltage on the grid side to obtain the voltage on the grid side. The triple-interleaved parallel boost converter includes: a combined inductor, a combined diode, a combined switching transistor, and a second capacitor; The combined diode is connected in parallel with the second capacitor, and the combined diode is connected in series with the combined switching transistor; the input terminal of the combined inductor is connected to the output terminal of the rectifier module; the output terminal of the combined inductor is connected to the connection terminal of the combined diode and the combined switching transistor; the second capacitor is also connected in parallel with the electrolytic cell; The single-phase half-bridge inverter includes: a first bridge arm, a second bridge arm, and an inverter inductor; The input terminal of the first bridge arm is connected to the positive output terminal of the single-phase boost converter; the output terminal of the second bridge arm is connected to the negative output terminal of the single-phase boost converter; the output terminal of the first bridge arm is connected to the input terminal of the second bridge arm; the input terminal of the inverter inductor is connected to the output terminals of the first bridge arm and the second bridge arm respectively; the output terminal of the inverter inductor is connected to the electrolytic cell.

2. The inverter-stage non-isolated electrolytic hydrogen production load characteristic test power supply according to claim 1, characterized in that, The rectifier module includes: a step-down transformer, a first three-phase bridge diode rectifier, a second three-phase bridge diode rectifier, a first inductor, and a first capacitor; One end of the step-down transformer is connected to the power grid side; the first three-phase bridge diode rectifier and the second three-phase bridge diode rectifier are connected in parallel; the other end of the step-down transformer is connected to the input terminals of the first three-phase bridge diode rectifier and the second three-phase bridge diode rectifier, respectively; the output terminal of the first three-phase bridge diode rectifier is connected to one end of the first inductor; the other end of the first inductor is connected to one end of the first capacitor; the other end of the first capacitor is connected to the output terminal of the second three-phase bridge diode rectifier.

3. The inverter-stage non-isolated electrolytic hydrogen production load characteristic test power supply according to claim 2, characterized in that, The secondary winding configuration of the step-down transformer includes star connection and delta connection.

4. The inverter-stage non-isolated electrolytic hydrogen production load characteristic test power supply according to claim 1, characterized in that, The combined inductor includes a second inductor, a third inductor, and a fourth inductor connected in parallel; the combined diode includes a first diode, a second diode, and a third diode connected in parallel; the combined switching transistor includes a first switching transistor, a second switching transistor, and a third switching transistor connected in parallel. The input terminals of the second inductor, the third inductor, and the fourth inductor are all connected to the output terminal of the rectifier module. The first switching transistor is connected in series with the first diode; the second switching transistor is connected in series with the second diode; the third switching transistor is connected in series with the third diode; The connection terminals of the third switch and the third diode are connected to the output terminal of the fourth inductor; The connection terminals of the second switching transistor and the second diode are connected to the output terminal of the third inductor; The connection terminals of the first switching transistor and the first diode are connected to the output terminal of the second inductor.

5. The inverter-stage non-isolated electrolytic hydrogen production load characteristic test power supply according to claim 1, characterized in that, The single-phase boost converter includes: a fifth inductor, a fourth switching transistor, a fourth diode, and a third capacitor; The input terminal of the fifth inductor is connected to the positive output terminal of the rectifier module; the output terminal of the fifth inductor is connected to the input terminal of the fourth switch and one end of the fourth diode; the other end of the fourth diode is connected to one end of the third capacitor; the other end of the third capacitor is connected to the output terminal of the fourth switch; and the output terminal of the fourth switch is also connected to the negative output terminal of the rectifier module.

Images