A single-phase bidirectional cell cascaded hybrid two-level rectifier

Abstract

A single-phase bidirectional cell cascaded hybrid two-level rectifier, comprising an alternating current power supply v in , a non-controlled diode rectifier bridge arm D1-D4, diodes D5-D 14 , inductors L, L1, L2, switching tubes S1, S a , capacitors C, resistors R. Diodes D7, D8, D9, D 10 and switching tubes S1 constitute a bidirectional switching unit. The hybrid rectifier can dynamically adjust its operating mode according to load demand and grid conditions, thereby achieving better power quality and energy efficiency. The single-phase bidirectional cell cascaded hybrid two-level rectifier proposed in the application can achieve higher energy conversion efficiency in a wider load range, and can significantly reduce energy loss compared with traditional two-level converters.

Description

TECHNICAL FIELD

[0001] The present application relates to a two-level rectifier, in particular to a single-phase bidirectional cell cascaded hybrid two-level rectifier. BACKGROUND

[0002] In the field of power electronics and power conversion, with the rapid development of renewable energy technologies and their increasing widespread applications, there is a growing demand for high-efficiency, stable, and reliable power conversion equipment. Traditional power converters, such as single-phase rectifiers and bidirectional converters, have been proven in certain applications, but as the types of loads diversify and the requirements for power quality improve, these traditional converters exhibit certain deficiencies in terms of efficiency, control complexity, and harmonic management.

[0003] A hybrid rectifier, by combining two cells in parallel, not only enhances the flexibility and adaptability of the system, but also improves the conversion efficiency and reduces harmonic distortion. Compared with traditional rectifiers, it can handle different load conditions in a wide range while ensuring efficient conversion of electrical energy. SUMMARY

[0004] The present application proposes a single-phase bidirectional cell cascaded hybrid two-level rectifier, which can dynamically adjust its operating mode according to load requirements and grid conditions, thereby achieving better power quality and energy efficiency. At the same time, this new hybrid rectifier can achieve higher energy conversion efficiency in a wide range of loads, not only enhancing the flexibility and adaptability of the system, but also improving the conversion efficiency and reducing harmonic distortion.

[0005] The technical solutions adopted by the present application are as follows:

[0006] A single-phase bidirectional cell cascaded hybrid two-level rectifier, the hybrid rectifier comprising:

[0007] uncontrolled diode rectifier bridge arms D1-D4, diodes D5-D 14 , inductors L, L1, L2, switching tubes S1, S a , capacitor C, resistor R;

[0008] AC power source v in One side of the AC power source is connected to the anode of diode D1, the cathode of diode D3, and one end of inductor L, respectively.

[0009] The cathodes of diodes D1 and D3 are connected to one end of inductor L1; the anodes of diodes D2 and D4 are connected to one end of inductor L2.

[0010] The anode of diode D3 and the cathode of diode D4 are connected to the other side of the AC power source v in and grounded.

[0011] The other end of the inductor L1 is connected to the anode of diode D5, the cathode of diode D6, the anode of diode D7, and the cathode of diode D8, respectively, and the connection node constitutes node a;

[0012] The cathode of diode D7 is connected to the drain of switch tube S1 and the cathode of diode D9, respectively;

[0013] The anode of diode D8 is connected to the source of switch tube S1 and the anode of diode D 10 , respectively;

[0014] The anode of diode D9 is connected to the cathode of diode D 10 , the anode of diode D 11 , the cathode of diode D 12 , and the other side of alternating current power supply v in and is grounded, and the connection node constitutes node n;

[0015] The other end of the inductor L1 is connected to the drain of switch tube S a , and the anode of diode D 13 , respectively;

[0016] The other end of the inductor L2 is connected to the source of switch tube S a , and the cathode of diode D 14 , respectively;

[0017] The cathode of diode D5 is connected to the cathode of diode D 11 , the cathode of diode D 13 , one end of capacitor C, and one end of load R, respectively;

[0018] The anode of diode D6 is connected to the anode of diode D 12 , the anode of diode D 14 , the other end of capacitor C, and the other end of load R, respectively.

[0019] The diodes D1, D2, D3, and D4 are connected to constitute a non-controlled rectifier circuit.

[0020] The diodes D7, D8, D9, and D 10 are connected with switch tube S1 to constitute a bidirectional switch unit.

[0021] The node a and node n constitute a two-port of the bidirectional switch unit.

[0022] The single-phase bidirectional unit cascaded hybrid two-level rectifier includes four working modes:

[0023] Mode 1: switch tube S1 is turned on, current flows through inductor L, diode D7, switch tube S1, diode D 10 , and then returns to alternating current power supply vin ; at this time, the AC power v in charges the inductor L, the inductor current linearly increases, the load R is powered by the capacitor C, and the voltage U an = 0.

[0024] Mode 2: the switch tube S1 is turned off, the current flows through the inductor L, the diode D5, the capacitor C, the diode D 12 , and returns to the AC power v in ; at this time, the inductor L and the AC power v in charge the capacitor C, the inductor current linearly decreases, and the voltage U an = +v o .

[0025] Mode 3: the switch tube S1 is turned on, the current flows through the diode D9, the switch tube S1, the diode D8, the inductor L, and returns to the AC power v in ; at this time, the AC power v in charges the inductor L, the inductor current linearly increases, the load R is powered by the capacitor C, and the voltage U an = 0.

[0026] Mode 4: the switch tube S1 is turned off, the current flows through the diode D 11 , the capacitor C, the diode D6, the inductor L, and returns to the AC power v in ; at this time, the AC power v in charges the inductor L and the capacitor C, the inductor current linearly decreases, and the voltage U an = -v o .

[0027] The diodes D 13 , D 14 can make the current of the capacitor C flow only to the load R, ensure the single-phase circulation of power; and during the mode switching process, are used as boost clamping diodes.

[0028] In the four working modes, the capacitor voltage v c = v o .

[0029] The single-phase bidirectional unit cascaded hybrid two-level rectifier has the following advantages:

[0030] 1. The single-phase bidirectional unit cascaded hybrid two-level rectifier not only enhances the flexibility and adaptability of the system, but also improves the conversion efficiency and reduces the harmonic distortion.

[0031] 2、The hybrid rectifier can achieve higher energy conversion efficiency in a wide load range, and can significantly reduce energy loss compared with traditional two-level converters. Through cascade design, better current distribution and elimination of high load problem of individual units can be achieved, enhancing the overall stability of the system.

[0032] 3、The single-phase bidirectional unit cascaded hybrid two-level rectifier of the application adopts a single-phase bidirectional unit cascaded hybrid structure, which can dynamically adjust its working mode according to load demand and grid conditions, thereby realizing better power quality and energy efficiency. At the same time, compared with traditional multi-phase systems, the structure reduces the number of components and simplifies the control and implementation difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0033] The application will be further described below in combination with the drawings and embodiments:

[0034] Figure 1 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier circuit principle diagram.

[0035] Figure 2 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier working mode 1 current path schematic diagram.

[0036] Figure 3 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier working mode 2 current path schematic diagram.

[0037] Figure 4 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier working mode 3 current path schematic diagram.

[0038] Figure 5 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier working mode 4 current path schematic diagram.

[0039] Figure 6 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier input voltage v in , current i1 waveform diagram.

[0040] Figure 7 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier input voltage v in , current i2 waveform diagram.

[0041] Figure 8 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier total input voltage v in , current i in waveform diagram.

[0042] Figure 9 It is a single-phase bidirectional unit cascaded hybrid two-level rectifier circuit bridge arm voltage U an waveform diagram.

[0043] Figure 10 The voltage v across the load R of the single-phase bidirectional cell cascaded hybrid two-level rectifier o Waveform diagram.

[0044] Figure 11 The output DC voltage v when the load R of the single-phase bidirectional cell cascaded hybrid two-level rectifier is halved o Waveform diagram. DETAILED DESCRIPTION

[0045] As shown in Figure 1 , a single-phase bidirectional cell cascaded hybrid two-level rectifier, the hybrid rectifier comprising:

[0046] An uncontrolled diode rectifier bridge arm D1-D4, diodes D5-D 14 , an inductor L, an inductor L1, an inductor L2, a switch tube S1, a switch tube S a , a capacitor C, a resistor R;

[0047] One side of the AC power source v in is connected to the anode of diode D1, the cathode of diode D3, and one end of inductor L, respectively;

[0048] 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;

[0049] The anode of diode D3 and the cathode of diode D4 are both connected to the other side of the AC power source v in and grounded;

[0050] The other end of inductor L1 is connected to the anode of diode D5, the cathode of diode D6, the anode of diode D7, and the cathode of diode D8, respectively, and the connection node constitutes node a;

[0051] The cathode of diode D7 is connected to the drain of switch tube S1 and the cathode of diode D9, respectively;

[0052] The anode of diode D8 is connected to the source of switch tube S1 and the anode of diode D 10 , respectively;

[0053] The anode of diode D9 is connected to the cathode of diode D 10 , the anode of diode D 11 , the cathode of diode D 12 , the other side of the AC power source v in and grounded, and the connection node constitutes node n;

[0054] The other end of inductor L1 is connected to the drain of switch tube S aDrain, diode D 13 anode;

[0055] The other end of the inductor L2 is connected to the switch tube S a Source, diode D 14 cathode;

[0056] The cathode of diode D5 is connected to diode D 11 The cathode of diode D 13 Cathode, one end of capacitor C, one end of load R;

[0057] The anode of diode D6 is connected to diode D 12 Anode of diode D 14 The anode of the capacitor, the other end of the capacitor C, and the other end of the load R.

[0058] The diodes D1 , D2 , D3 , and D4 are connected to form an uncontrolled rectifier circuit.

[0059] The diodes D7, D8, D9, D 10 Connected with the switch tube S1 to form a bidirectional switch unit.

[0060] The node a and the node n constitute two ports of the bidirectional switch unit.

[0061] The following describes the specific working principle of a single-phase bidirectional unit cascade 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:

[0062] Figure 2 Schematic diagram of the current path in mode 1: switch tube S1 is turned on, and the current flows through inductor L, diode D7, switch tube S1, and diode D 10 After returning to 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 3 Schematic diagram of the current path in mode 2: switch tube S1 is turned off, and the current flows through inductor L, diode D5, capacitor C, and diode D 12 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 ;

[0064] Figure 4For the mode 3 current path schematic: switch S1 is on, current flows through diode D9, switch S1, diode D8, inductor L and returns to power supply v in ; at this time, power supply v in charges inductor L and stores energy, inductor current increases linearly, load R is powered by capacitor C, voltage U an = 0

[0065] Figure 5 For the mode 4 current path schematic: switch S1 is off, current flows through diode D 11 , capacitor C, diode D6, inductor L and returns to power supply v in ; at this time, power supply v in charges capacitor C with inductor L, inductor current decreases linearly, voltage U an = -v o .

[0066] Table 1 is a correspondence table of rectifier switch pulse distribution mode, DC side capacitor working state and voltage U an , where the turn-on and turn-off of the switch are represented by "1" and "0", respectively.

[0067] Table 1 is a correspondence table of rectifier switch pulse distribution mode, DC side capacitor working state and voltage U an

[0068]

[0069] To verify that the single-phase bidirectional unit cascaded hybrid two-level rectifier of the application can realize two-level function, under the single-cycle control strategy, experimental verification is carried out, and the experimental parameters are as follows: AC power frequency is 50 Hz, input voltage effective value is 220 V, inductance L is 50 mH, capacitance is 22000 uF, switching frequency is 10 kHz, boost inductance L1 = L2 = 2 mH, and load is 50 Ω.

[0070] Figure 6 Fig. 6 is a waveform diagram of input voltage v in and input side current i1 of the single-phase bidirectional unit cascaded hybrid two-level rectifier, the input current i1 can effectively follow the AC input voltage v in , further reduces the harmonic content of the input side current, and realizes the power factor correction function.

[0071] Figure 7 Fig. 7 is a waveform diagram of input voltage v in and input side current i2 of the single-phase bidirectional unit cascaded hybrid two-level rectifier, the input current i2 can effectively follow the AC input voltage v in , further reduces the harmonic content of the input side current, and realizes the power factor correction function.

[0072] ​Figure 8 The total input voltage v of the single-phase bidirectional unit cascaded hybrid two-level rectifier circuit in The total input current i in The input current i waveform chart in The AC input voltage v can be effectively followed in Further reduce the input side current harmonic content, and realize the power factor correction function.

[0073] Figure 9 The bridge arm voltage U of the single-phase bidirectional unit cascaded hybrid two-level rectifier circuit an The waveform chart shows that the voltage is alternately 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 that the output end potential has 0, v o Two.

[0074] Figure 10 The output DC voltage v of the single-phase bidirectional unit cascaded hybrid two-level rectifier circuit o The waveform chart, the two-level rectifier designed by the application has an input of 220V and an output of 400V, and the output DC voltage v Figure 10 The waveform shows that the voltage v o Stable output.

[0075] Figure 11 The output DC voltage v of the single-phase bidirectional unit cascaded hybrid two-level rectifier circuit when the load is halved o The output DC voltage v waveform chart o The output DC voltage v waveform is slightly adjusted at 0.25s-0.3s and quickly recovers to a stable state, indicating that the system has strong dynamic adjustment ability and good disturbance rejection performance.

[0076] The hybrid rectifier can dynamically adjust its working mode according to the load demand and grid conditions, thereby realizing better power quality and energy efficiency.

[0077] The single-phase bidirectional unit cascaded hybrid two-level rectifier proposed by the application can realize higher energy conversion efficiency in a wider load range, and can significantly reduce energy loss compared with traditional two-level converters. The single-phase bidirectional unit cascaded two-level hybrid rectifier can effectively solve the problems of traditional rectifiers in power quality, adaptability and efficiency, and provide more reliable and efficient conversion solutions for the future power electronic market. This innovation not only meets the needs of modern power systems, but also lays the foundation for the widespread application and efficient use of green energy.

Claims

1. A single-phase bidirectional unit cascade hybrid two-level rectifier, characterized in that: The rectifier includes: Uncontrolled diode rectifier bridge arms D1~D4, diodes D5~D 14 ,inductance L、 inductance L 1. Inductor L 2. Switching tube S 1. Switching tube S a ,capacitance C ,resistance R ; AC power supply v in One side is connected to the anode of diode D1, the cathode of diode D3, and the inductor L one end; The cathode of diode D1 and the cathode of diode D3 are both connected to the inductor The anode of diode D2 and the anode of diode D4 are both connected to the inductor one end; The anode of diode D3 and the cathode of diode D4 are both connected to the AC power supply. v in and ground the other side; inductance The other end of the diode is connected to the anode of the diode D5, the cathode of the diode D6, the anode of the diode D7, and the cathode of the diode D8, and the connection node thereof constitutes a node a; The cathode of diode D7 is connected to the switch tube S 1's drain, diode D9's cathode; The anode of diode D8 is connected to the switch tube S 1's source, diode D 10 anode; The anode of diode D9 is connected to diode D 10 The cathode of diode D 11 Anode of diode D 12 cathode, AC power supply v in The other side of the node is connected to the ground, and the connection node constitutes node n; inductance The other end is connected to the switch tube Drain, diode D 13 anode; inductance The other end is connected to the switch tube Source, diode D 14 cathode; The cathode of diode D5 is connected to diode D 11 The cathode of diode D 13 cathode, capacitor C One end of the load one end; The anode of diode D6 is connected to diode D 12 Anode of diode D 14 Anode, capacitor C The other end of the load the other end; The single-phase bidirectional unit cascade hybrid two-level rectifier includes four operating modes: Mode 1: Switching tube S 1 is on, current flows through the inductor L , diode D7, switch tube S 1. Diode D 10 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 By capacitor C Power supply, voltage U an =0; Mode 2: Switching tube S 1 is off, current flows through the inductor L , diode D5, capacitor C , diode D 12 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 ; Mode 3: Switching tube S 1 is turned on, current flows through diode D9, and the switch tube , diode D8, 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 By capacitor C Power supply, voltage U an =0; Mode 4: Switching Tube S 1 is turned off, current flows through diode D 11 ,capacitance C , diode D6, inductor L After returning to AC power v in ; At this time, the AC power v in With inductance L Towards capacitance C Charging, the inductor current decreases linearly, the voltage U an = -v o .

2. The single-phase bidirectional unit cascade hybrid two-level rectifier according to claim 1, characterized in that: The diodes D1 , D2 , D3 , and D4 are connected to form an uncontrolled rectifier circuit.

3. The single-phase bidirectional unit cascade hybrid two-level rectifier according to claim 1, characterized in that: The diodes D7, D8, D9, D 10 With switch tube S 1 connection constitutes a bidirectional switch unit.

4. The single-phase bidirectional unit cascade hybrid two-level rectifier according to claim 1, characterized in that: The node a and the node n constitute two ports of the bidirectional switch unit.

5. The single-phase bidirectional unit cascade hybrid two-level rectifier according to claim 1, characterized in that: Use diode D 13 、D 14 Capacitor C The current flows only to the load 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 bidirectional unit cascade 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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