A single-phase symmetrical bridge arm dual-path hybrid two-level rectifier

Abstract

A single-phase symmetric bridge arm double-path hybrid two-level rectifier, comprising an alternating current power supply v in , uncontrolled diode bridge arms D1-D4, diodes D5-D 12 , inductors L, L1, L2, switching tubes S a , switching tubes S1, S2, capacitor C, resistor R. Diodes D7, D8 and switching tubes S1, S2 constitute a symmetric bridge arm structure unit. The hybrid rectifier can be flexibly expanded according to requirements, increase parallel components to improve power output, while reducing the rating and loss of devices, improve efficiency and power density. The single-phase symmetric bridge arm double-path hybrid two-level rectifier has the advantages of less power switching device, no control dead zone, low harmonic content, flexible adjustment of two parallel rectifier power ratio, etc.

Description

Technical Field

[0001] The present invention relates to a two-level rectifier, in particular to a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier. Background Art

[0002] In the development of modern power electronics, rectification is a crucial means of achieving power conversion and regulation. With the widespread adoption of renewable energy sources such as wind and solar power, the demand for power converters with high efficiency, high power factor, and low harmonics is increasing. Against this backdrop, hybrid rectifiers, as a novel power conversion solution, show promising application prospects.

[0003] Furthermore, with increasing demands for power quality, harmonic suppression has become a crucial metric in rectifier design. Hybrid two-level rectifiers can effectively reduce harmonic content by improving the output current waveform, thereby enhancing power quality. In modern power systems, particularly when integrated with renewable energy, rectifier performance directly impacts the efficiency and stability of the entire system. Two-level hybrid rectifiers integrate multiple rectification and conversion advantages, offering high efficiency, high power factor, and low harmonics. With the continuous advancement of power electronics technology, this structure will play an increasingly important role in smart grids, renewable energy integration, and efficient power management systems, becoming a key research direction in the future of power electronics. Summary of the Invention

[0004] This invention proposes a single-phase symmetrical bridge-arm dual-path hybrid two-level rectifier. This symmetrical bridge-arm design effectively balances current and reduces harmonics, enabling dual-path current flow and optimizing power transmission. Furthermore, this rectifier structure enables a wider input voltage range, adapting to various input conditions and ensuring output voltage stability. By incorporating the characteristics of symmetrical bridge arms into this design, harmonic distortion is further reduced, the power factor is significantly improved, and the power quality of the power grid is enhanced.

[0005] The technical solution adopted by the present invention is:

[0006] A single-phase symmetrical bridge arm dual-path hybrid two-level rectifier, the rectifier comprising:

[0007] Uncontrolled diode rectifier bridge arms D1 to D4, diodes D5 to D 12 , inductor L, inductor L1, inductor L2, switch tube S a , switch tube S1, switch tube S2, capacitor C, resistor R;

[0008] AC power supply v in One side is connected to the anode of diode D1, the cathode of diode D2, and one end of inductor L respectively;

[0009] The other end of the inductor L is connected to the anode of the diode D5, the cathode of the diode D6, the anode of the diode D7, and the source of the switch S2, respectively, and the connection nodes constitute the node a;

[0010] The anode of diode D3 and the cathode of diode D4 are both connected to the AC power supply v in and grounded on the other side;

[0011] The cathode of diode D1 and the cathode of diode D3 are both connected to one end of inductor L1; the anode of diode D2 and the anode of diode D4 are both connected to one end of inductor L2;

[0012] The cathode of the diode D7 is connected to the source of the switch tube S1, and the drain of the switch tube S2 is connected to the cathode of the diode D8;

[0013] The cathode of diode D5 is connected to the cathode of diode D9, one end of capacitor C, and diode D 11 The cathode of the load R;

[0014] The anode of diode D6 is connected to diode D 10 The anode of the capacitor C, the other end of the diode D 12 The anode and the other end of the load R;

[0015] The drain of the switch tube S1 is connected to the anode of the diode D8, the anode of the diode D9, and the anode of the diode D 10 cathode, AC power supply v in The other side of the , and grounded; its connection node constitutes node n;

[0016] The other end of the inductor L1 is connected to the diode D 11 Anode, switch tube S a drain;

[0017] The other end of the inductor L2 is connected to the diode D 12 The cathode of the switch tube S a Source.

[0018] The diodes D1 to D4 are connected to form an uncontrolled rectifier circuit.

[0019] The diodes D7 and D8 are connected to the switch tubes S1 and S2 to form a symmetrical bridge arm structure unit.

[0020] The node a and the node n constitute two ports of a symmetrical bridge arm unit.

[0021] A single-phase symmetrical bridge-arm dual-path hybrid two-level rectifier includes four operating modes:

[0022] Mode 1: Switch S1 is on, switch S2 is off, current flows through inductor L, diode D7, switch S1 and then returns to power supply V. in ; At this time, the AC power supply v in The inductor L is charged to store energy, the inductor current increases linearly, the load R is powered by the capacitor C, and the voltage U an =0;

[0023] Mode 2: Switches S1 and S2 are turned off, and the current flows through inductor L, diode D5, capacitor C, and diode D. 10 Then return the AC power supply v in ; At this time, the inductor L and the AC power supply v in At the same time, the capacitor C is charged, the inductor current decreases linearly, and the voltage U an =+v o ;

[0024] Mode 3: Switch S2 is on, switch S1 is off, and the current flows through diode D8, switch S2, and inductor L before returning to the AC power supply v in ; At this time, the AC power supply v in The inductor L is charged to store energy, the inductor current increases linearly, the load R is powered by the capacitor C, and the voltage U an =0;

[0025] Mode 4: Switches S1 and S2 are turned off, and the current flows through diode D9, capacitor C, diode D6, and inductor L before returning to the AC power supply v in ; At this time, the AC power supply v in As the inductor L charges the capacitor C, the inductor current decreases linearly and the voltage U an =-v o .

[0026] Use diode D 11 、D 12 It allows the current of capacitor C to flow only to load R, ensuring single-phase power flow; at the same time, it acts as a boost clamping diode during mode switching.

[0027] In the four working modes, the capacitor voltage v c =v o .

[0028] The present invention provides a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier, and the technical effects are as follows:

[0029] 1) The present invention discloses a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier with the advantages of fewer power switching devices, no dead zone in control, low harmonic content, and flexible adjustment of the power ratio of the two parallel rectifiers. It is suitable for medium and high power applications with unidirectional energy flow and has good application prospects.

[0030] 2) This invention features a single-phase, symmetrical, dual-path hybrid two-level rectifier. The dual-path design allows users to adjust the power ratio of the parallel rectifiers as needed, providing greater flexibility to accommodate varying load conditions and operating scenarios. Through an optimized switching strategy, output harmonics are significantly reduced, ensuring excellent power quality and complying with stricter electricity standards.

[0031] 3) The present invention proposes a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier. This single-phase symmetrical bridge arm dual-path hybrid structure achieves a wider input voltage range, adapts to various input conditions, and ensures output voltage stability. Furthermore, it achieves dead-zone-free control, avoiding potential energy loss during dead time and improving overall system efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings and examples:

[0033] Figure 1 This is a circuit schematic diagram of a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to the present invention.

[0034] Figure 2 Schematic diagram of the current path of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier in working mode 1 of the present invention.

[0035] Figure 3 Schematic diagram of the current path of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier in working mode 2 of the present invention.

[0036] Figure 4 Schematic diagram of the current path of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier in working mode 3 of the present invention.

[0037] Figure 5 Schematic diagram of the current path of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier in working mode 4 of the present invention.

[0038] Figure 6 The input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention is in , current i1 waveform.

[0039] Figure 7 The input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention is in , current i2 waveform.

[0040] Figure 8 The total input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention is in , current i in Waveform graph.

[0041] Figure 9The bridge arm voltage U of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier circuit of the present invention is an Waveform graph.

[0042] Figure 10 The voltage v across the load R of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention is o Waveform graph.

[0043] Figure 11 The output DC voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention when the load R is halved o Waveform graph. DETAILED DESCRIPTION

[0044] like Figure 1 As shown, a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier includes:

[0045] Uncontrolled diode rectifier bridge arms D1 to D4, diodes D5 to D 12 , inductor L, inductor L1, inductor L2, switch tube S a , switch tube S1, switch tube S2, capacitor C, resistor R;

[0046] AC power supply v in One side is connected to the anode of diode D1, the cathode of diode D2, and one end of inductor L respectively;

[0047] The other end of the inductor L is connected to the anode of the diode D5, the cathode of the diode D6, the anode of the diode D7, and the source of the switch S2, respectively, and the connection nodes constitute the node a;

[0048] The anode of diode D3 and the cathode of diode D4 are both connected to the AC power supply v in and grounded on the other side;

[0049] The cathode of diode D1 and the cathode of diode D3 are both connected to one end of inductor L1; the anode of diode D2 and the anode of diode D4 are both connected to one end of inductor L2;

[0050] The cathode of the diode D7 is connected to the source of the switch tube S1, and the drain of the switch tube S2 is connected to the cathode of the diode D8;

[0051] The cathode of diode D5 is connected to the cathode of diode D9, one end of capacitor C, and diode D 11 The cathode of the load R;

[0052] The anode of diode D6 is connected to diode D 10 The anode of the capacitor C, the other end of the diode D 12 The anode and the other end of the load R;

[0053] The drain of the switch tube S1 is connected to the anode of the diode D8, the anode of the diode D9, and the anode of the diode D 10 cathode, AC power supply v in The other side of the , and grounded; its connection node constitutes node n;

[0054] The other end of the inductor L1 is connected to the diode D 11 Anode, switch tube S a drain;

[0055] The other end of the inductor L2 is connected to the diode D 12 The cathode of the switch tube S a Source.

[0056] The diodes D1 to D4 are connected to form an uncontrolled rectifier circuit.

[0057] The diodes D7 and D8 are connected to the switch tubes S1 and S2 to form a symmetrical bridge arm structure unit.

[0058] The node a and the node n constitute two ports of a symmetrical bridge arm unit.

[0059] The following describes the specific working principle of a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier circuit of the present invention. The two-level rectifier has four working modes, among which: capacitor voltage v c =v o , the specific analysis process is as follows:

[0060] Figure 2 Schematic diagram of the current path in mode 1: switch S1 is on, switch S2 is off, and the current flows through the inductor L, diode D7, and switch S1 before returning to the power supply V. in ; At this time, the power supply v in The inductor L is charged to store energy, the inductor current increases linearly, the load R is powered by the capacitor C, and the voltage U an =0;

[0061] Figure 3 Schematic diagram of the current path in mode 2: switches S1 and S2 are turned off, and the current flows through inductor L, diode D5, capacitor C, and diode D 10 After returning to power supply v in ; At this time, the inductor L and the power supply v in At the same time, the capacitor C is charged, the inductor current decreases linearly, and the voltage U an =+v o ;

[0062] Figure 4 This is a diagram of the current path in mode 3: switch S2 is on, switch S1 is off, and the current flows through diode D8, switch S2, and inductor L before returning to the power supply v in; At this time, the power supply v in The inductor L is charged to store energy, the inductor current increases linearly, the load R is powered by the capacitor C, and the voltage U an =0;

[0063] Figure 5 Schematic diagram of the current path in mode 4: Switches S1 and S2 are turned off, and the current flows through diode D9, capacitor C, diode D6, inductor L, and then returns to the power supply v in ; At this time, the power supply v in As the inductor L charges the capacitor C, the inductor current decreases linearly and the voltage U an =-v o ;

[0064] Table 1 shows the pulse distribution mode of the rectifier switch tube, the working state of the DC side capacitor and the voltage U an Correspondence table, where the on and off of the switch tube are represented by "1" and "0" respectively.

[0065] Table 1 Rectifier switch pulse distribution mode, DC side capacitor working state and voltage U an Correspondence table

[0066]

[0067] To verify that the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention can achieve two-level function, experimental verification is carried out under the single-cycle control strategy. The experimental parameters are: AC power frequency of 50Hz, input voltage RMS value of 220V, inductor L = 50mH, capacitor 50000uF, switching frequency of 10kHz, boost inductor L1 = L2 = 2mH, and load 50Ω.

[0068] Figure 6 The input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is in , input side current i1 waveform. Input current i1 can effectively follow the AC input voltage v in , further reducing the harmonic content of the input side current and realizing the power factor correction function.

[0069] Figure 7 The input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is in , Input side current i2 waveform, input current i2 can effectively follow the AC input voltage v in , further reducing the harmonic content of the input side current and realizing the power factor correction function.

[0070] Figure 8 is the total input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier in , total current on the input side i inWaveform, input current i in Can effectively follow the AC input voltage v in , further reducing the harmonic content of the input side current and realizing the power factor correction function.

[0071] Figure 9 The bridge arm voltage U of the single-phase symmetrical dual-path hybrid two-level rectifier is an The waveform shows that the voltage is alternating between positive and negative, and is almost symmetrical. The two-level effect is good, and the experimental verification is consistent with the theoretical analysis results. The two levels are the output terminal potential 0, v o Two types.

[0072] Figure 10 The output DC voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is o Waveform diagram, the present invention designs a two-level rectifier with input 220V / output 400V, Figure 10 The waveform shows that the voltage v o Stable output.

[0073] Figure 11 The output DC voltage v is a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier when the load is halved. o Waveform, output DC voltage v o The waveform is slightly adjusted from 0.25s to 0.3s and quickly returns to a stable state, indicating that the system has strong dynamic adjustment capability and good anti-disturbance performance.

[0074] The hybrid rectifier can be flexibly expanded according to demand, and parallel components can be added to increase power output, while reducing device ratings and losses, and improving efficiency and power density.

[0075] Compared with traditional two-level converters, the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier proposed in the present invention has the advantages of fewer power switching devices, no dead zone in control, low harmonic content, and flexible adjustment of the power ratio of two parallel rectifiers.

Claims

1. A single-phase symmetrical bridge arm dual-path hybrid two-level rectifier, characterized in that The rectifier includes: Uncontrolled diode rectifier bridge arms D1~D4, diodes D5~D 12 ,inductance L、 inductance L 1. Inductor L 2. Switching tube S a , switch tube S 1. Switching tube S 2. Capacitor C , load resistance R ; AC power supply v in One side is connected to the anode of diode D1, the cathode of diode D2, and the inductor one end; inductance The other end is connected to the anode of diode D5, the cathode of diode D6, the anode of diode D7, and the switch tube S 2's source, whose connected nodes constitute node a; The anode of diode D3 and the cathode of diode D4 are both connected to the AC power supply. v in and grounded on the other side; The cathode of diode D1 and the cathode of diode D3 are both connected to the inductor L 1; the anode of diode D2 and the anode of diode D4 are connected to the inductor L One end of 2; The cathode of diode D7 is connected to the switch tube S 1's drain, switch tube S The drain of 2 is connected to the cathode of diode D8; The cathode of diode D5 is connected to the cathode of diode D9, capacitor C One end of the diode D 11 Cathode, load resistance R one end; The anode of diode D6 is connected to diode D 10 Anode, capacitor C The other end of the diode D 12 Anode, load resistance R the other end; Switching tube S The source of 1 is connected to the anode of diode D8, the anode of diode D9, and the anode of diode D 10 cathode, AC power supply v in The other side of the , and grounded; its connection node constitutes node n; inductance L The other end of 1 is connected to diode D 11 Anode, switch tube drain; inductance L The other end of 2 is connected to diode D 12 Cathode, switch tube source; The rectifier includes 4 working modes: Mode 1: Switching tube S 1 is on, the switch tube S 2 is turned off, current flows through the inductor L , diode D7, switch tube S 1 after returning to power v in ; At this time, the AC power v in Directional Inductance L Charging energy storage, inductor current increases linearly, load resistance R By capacitor C Power supply, voltage U an =0; Mode 2: Switching tube S 1. S 2 is turned off, current flows through the inductor L , diode D5, capacitor C , diode D 10 After returning to AC power v in ; At this time, the inductance L With AC power v in At the same time, the capacitor C Charging, the inductor current decreases linearly, the voltage U an = +v o ; v o Indicates load resistance R Voltage across both ends; Mode 3: Switching tube S 2 conduction, switch tube S 1 is turned off, current flows through diode D8, and the switch tube S 2. Inductor L After returning to AC power v in ; At this time, the AC power v in Directional Inductance L Charging energy storage, inductor current increases linearly, load resistance R By capacitor C Power supply, voltage U an =0; Mode 4: Switching tube S 1. S 2 is turned off, current flows through diode D9, capacitor C , diode D6, inductor L After returning to AC power v in ; At this time, the AC power v in With inductor L Towards capacitance C Charging, the inductor current decreases linearly, the voltage U an = -v o .

2. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 1, characterized in that: The diodes D1 to D4 are connected to form an uncontrolled rectifier circuit.

3. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 1, characterized in that: The diodes D7, D8 and the switch tube S 1. S 2 are connected to form a symmetrical bridge arm structural unit.

4. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 1, characterized in that: The node a and the node n constitute two ports of a symmetrical bridge arm unit.

5. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 1, characterized in that: Use diode D 11 、D 12 Capacitor C The current flows only to the load resistor R flow, ensuring the single-phase flow of power; at the same time, during the mode switching process, it is used as a boost clamping diode.

6. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 1, characterized in that: In the four working modes, the capacitor voltage v c =v o .

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