Single-phase symmetrical bridge arm double-path hybrid two-level rectifier

Abstract

A single-phase symmetrical bridge arm double-path hybrid two-level rectifier comprises an alternating current power supply vin, uncontrolled diode rectifier bridge arms D1-D4, diodes D5-D12, an inductor L, an inductor L1, an inductor L2, a switch tube Sa, a switch tube S1, a switch tube S2, a capacitor C and a resistor R. And the diodes D7 and D8 and the switching tubes S1 and S2 form a symmetrical bridge arm structure unit. The hybrid rectifier can be flexibly expanded according to requirements, parallel assemblies are added to improve power output, meanwhile, the quota and loss of devices are reduced, and efficiency and power density are improved. Compared with a traditional two-level converter, the single-phase symmetrical bridge arm double-path mixed two-level rectifier has the advantages that the number of power switch devices is small, no dead zone is controlled, the harmonic content is low, and the power ratio of the two parallel rectifiers can be flexibly adjusted.

Description

Technical Field

[0001] The 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 technology, rectification is an important means to achieve power conversion and regulation. With the widespread application of renewable energy such as wind and solar energy, the demand for high-efficiency, high power factor and low harmonic power converters is also increasing. In this context, hybrid rectifiers, as a new power conversion solution, show good application prospects.

[0003] In addition, with the continuous improvement of power quality requirements, harmonic suppression has become an important indicator for rectifier design. The hybrid two-level rectifier can effectively reduce the harmonic share by improving the output current waveform, thereby improving the power quality. In modern power systems, especially in application scenarios combined with renewable energy, the performance of the rectifier directly affects the efficiency and stability of the entire system. The two-level hybrid rectifier integrates multiple rectification and conversion advantages, and has the advantages of 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, and will become an important research direction in the field of power electronics in the future. Summary of the invention

[0004] The present invention proposes a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier, which can effectively balance current and reduce harmonics through the symmetrical bridge arm design, realize dual-path current flow, and thus optimize the power transmission process. At the same time, the rectifier structure can achieve a wider input voltage range, adapt to a variety of input conditions, and ensure the stability of the output voltage. By incorporating the characteristics of the symmetrical bridge arm into the design, the harmonic distortion is further reduced, the power factor is significantly improved, and the power quality of the power grid is improved.

[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 supplyv in One side of the diode D1 is connected to the anode of the diode D1, the cathode of the diode D2, and one end of the inductor L;

[0009] The other end of the inductor L is respectively 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 tube S2, and the connection nodes constitute a 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;

[0011] The cathode of the diode D1 and the cathode of the diode D3 are both connected to one end of the inductor L1; the anode of the diode D2 and the anode of the diode D4 are both connected to one end of the 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 10 The cathode of the AC power supply v in The other side of is connected to the ground; 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 with 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 working modes:

[0022] Mode 1: Switch S1 is turned on, switch S2 is turned off, the current flows through the inductor L, diode D7, and then returns to the power supply v after the switch S1 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 After returning to the AC power supply v in ; At this time, the inductance 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 turned on, switch S1 is turned 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 4 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 single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of 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. It is suitable for medium and high power occasions with unidirectional energy flow and has good application prospects.

[0030] 2) The present invention is a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier. The dual-path design allows users to adjust the power ratio of the parallel rectifier according to needs, providing greater flexibility to adapt to different load conditions and operating conditions. Through the optimized switching strategy, the output harmonics can be significantly reduced, so that the power quality is well guaranteed and meets more stringent power standards.

[0031] 3) The present invention is a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier, which adopts a single-phase symmetrical bridge arm dual-path hybrid structure, can achieve a wider input voltage range, adapt to a variety of input conditions, and ensure the stability of the output voltage. In addition, it can achieve dead-zone-free control, avoid energy loss that may occur during the dead zone time, and improve the overall efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

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

[0034] Figure 2 It is a 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 It is a 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 It is a 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 It is a 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 is the total input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention in 、Current i in Waveform graph.

[0041] Fig. 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] Fig.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] Fig.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, the rectifier comprises:

[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 supplyv in One side of the diode D1 is connected to the anode of the diode D1, the cathode of the diode D2, and one end of the inductor L;

[0047] The other end of the inductor L is respectively 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 tube S2, and the connection nodes constitute a 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;

[0049] The cathode of the diode D1 and the cathode of the diode D3 are both connected to one end of the inductor L1; the anode of the diode D2 and the anode of the diode D4 are both connected to one end of the 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 10 The cathode of the AC power supply v in The other side of is connected to the ground; 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 with 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 specific working principle of a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention is described below. The two-level rectifier has four working modes, among which: the capacitor voltage v c =v o , the specific analysis process is as follows:

[0060] Figure 2 This is a schematic diagram of the current path in mode 1: switch tube S1 is turned on, switch tube S2 is turned off, and the current flows through the inductor L, diode D7, and then returns to the power supply v after the switch tube S1 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: switch tubes 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 schematic diagram of the current path in mode 3: switch tube S2 is turned on, switch tube S1 is turned off, and the current flows through diode D8, switch tube S2, inductor L and then returns 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 This is a schematic diagram of the current path in mode 4: the switches S1 and S2 are turned off, and the current flows through the 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] In order to verify that the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier of the present invention can realize the two-level function, experimental verification is carried out under the single-cycle control strategy. The experimental parameters are: AC power supply frequency is 50Hz, input voltage effective value is 220V, inductance L=50mH, capacitance 50000uF, switching frequency is 10kHz, boost inductance L1=L2=2mH, load 50Ω.

[0068] Figure 6 The input voltage v is the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier 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 is the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier 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 The total input voltage v of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is in , total input current 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] Fig. 9 The bridge arm voltage U of the single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is an From the waveform, we can see that the voltage is alternating between positive and negative and is almost symmetrical. The two-level effect is good, and the experimental verification and theoretical analysis results are consistent. The two-level is the output terminal potential of 0, v o Two types.

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

[0073] Fig.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 at 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, adding parallel components to increase power output, while reducing device ratings and losses, and improving efficiency and power density.

[0075] Compared with the traditional two-level converter, 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 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; AC power supplyv in One side of the diode D1 is connected to the anode of the diode D1, the cathode of the diode D2, and one end of the inductor L; The other end of the inductor L is respectively 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 tube S2, and the connection nodes constitute a 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; The cathode of the diode D1 and the cathode of the diode D3 are both connected to one end of the inductor L1; the anode of the diode D2 and the anode of the diode D4 are both connected to one end of the inductor L2; 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; 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; 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; The drain of the switch tube S1 is connected to the anode of the diode D8, the anode of the diode D9, and the 10 The cathode of the AC power supply v in The other side of is connected to the ground; its connection node constitutes node n; The other end of the inductor L1 is connected to the diode D 11 Anode, switch tube S a Drain; The other end of the inductor L2 is connected to the diode D 12 The cathode of the switch tube S a Source.

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

3. According to claim 1, a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is characterized in that: The diodes D7 and D8 are connected with the switch tubes S1 and S2 to form a symmetrical bridge arm structure unit.

4. According to claim 1, a single-phase symmetrical bridge arm dual-path hybrid two-level rectifier is 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 any one of claims 1 to 4, characterized in that: Includes 4 working modes: Mode 1: Switch S1 is turned on, switch S2 is turned 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; 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 the AC power supply v in ; At this time, the inductance 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 ; Mode 3: Switch S2 is turned on, switch S1 is turned 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; 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 .

6. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 5, characterized in that: 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.

7. The single-phase symmetrical bridge arm dual-path hybrid two-level rectifier according to claim 5, characterized in that: In the four working modes, the capacitor voltage v c =v o .

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