10-pulse rectifier with auxiliary single-phase pulse width adjustable current circuit

Abstract

This invention relates to a 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, belonging to the field of power electronics technology. It addresses the problem of further suppressing input current harmonics in a 10-pulse rectifier without significantly increasing the complexity of three-phase / five-phase transformers. The invention introduces an auxiliary single-phase pulse width adjustable current circuit to control the PWM signal output from the PWM signal drive circuit within this circuit. This PWM signal controls the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit, controlling its on / off state. When the grid-side input voltage or the voltage across the load changes, the operation of the switching transistor in the active harmonic suppression auxiliary circuit changes accordingly, causing the input current of the active harmonic suppression auxiliary circuit to follow the given signal i of the injected current. sref The corresponding changes ensure effective suppression of harmonics in the input current of the 10-pulse rectifier. This invention is primarily used for rectification.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a low-harmonic 10-pulse rectifier. Background Technology

[0002] Three-phase rectifiers have advantages such as simple circuit structure, high reliability, and low EMI, and are widely used in industrial fields as interface circuits between electrical equipment and the power grid, such as variable frequency speed control systems, electric propulsion systems, new energy power generation, and electrochemical processing. However, the strong nonlinearity of rectifier diodes can inject a large number of harmonics into the power grid, causing serious harmonic pollution.

[0003] To actively suppress input current harmonics in three-phase rectifiers, various methods have been proposed. These can be broadly categorized into three types:

[0004] The first method is to use PWM rectification technology. Three-phase PWM rectifiers have the advantages of good harmonic suppression, high input power factor and four-phase limited operation, and have been widely used in small and medium power applications. However, the switching transistors in the three-phase PWM rectifier are the main switching transistors. When applied to high power applications, they will be subjected to higher voltage and current levels, resulting in greater switching losses and more severe electromagnetic interference.

[0005] The second method involves using a phase-shifting transformer to increase the pulse count of the rectifier, thereby effectively suppressing the input current harmonics. As the pulse count of the rectifier increases, the input current harmonics gradually decrease. However, in practical applications, only when the pulse count of the rectifier increases to 24 pulses or more can the harmonic standard requirements be met. This not only significantly increases the manufacturing difficulty of the phase-shifting transformer but also multiplies the number of components in the rectifier, increasing its cost, weight, and size.

[0006] The third approach involves using multiphase transformers to construct multi-pulse rectifiers, thereby suppressing input current harmonics. For example, three-phase / five-phase or three-phase / seven-phase transformers can be used to construct 10-pulse or 14-pulse rectifiers, further suppressing input current harmonics. However, their harmonic suppression capabilities remain limited and still cannot meet the requirements of industrial applications. Although further increasing the number of phases in the multiphase transformer can further reduce the input current harmonics of the rectifier, the manufacturing difficulty of multiphase transformers will increase significantly, making them more difficult to process and manufacture.

[0007] Therefore, how to further suppress input current harmonics and obtain a low-harmonic 10-pulse rectifier that meets harmonic standards without significantly increasing the complexity of three-phase / five-phase transformers has become an urgent problem to be solved. Summary of the Invention

[0008] The purpose of this invention is to solve the problem of how to further suppress the input current harmonics of a 10-pulse rectifier without significantly increasing the complexity of the three-phase / five-phase transformer. This invention provides a 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, which includes the following two structures.

[0009] First structure:

[0010] A 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, comprising a three-phase / five-phase transformer, a five-phase rectifier bridge, and an auxiliary single-phase pulse width adjustable current circuit;

[0011] The auxiliary single-phase pulse width adjustable current circuit includes an auxiliary single-phase transformer, an active harmonic suppression auxiliary circuit, a balancing reactor, a subtractor, a load current sampling circuit, a synchronization signal sampling circuit, a fifth-harmonic triangular wave generation circuit, an input current sampling circuit, an injection current setting circuit, a PWM signal drive circuit, a hysteresis comparator, and a capacitor C. 11 and capacitor C 21 ;

[0012] Three-phase / five-phase transformers are used to shift the three-phase voltage output from the power grid to generate a five-phase voltage with a phase difference of 72° between adjacent phases. This five-phase voltage serves as the input voltage of a five-phase rectifier bridge.

[0013] The positive output terminal of the five-phase rectifier bridge and capacitor C 11 One end of the rectifier bridge, the positive terminal Q of the active harmonic suppression auxiliary circuit output side, and the positive terminal of the load are connected simultaneously. The negative terminal of the five-phase rectifier bridge is connected to the negative terminal P of the active harmonic suppression auxiliary circuit output side, and the capacitor C is connected to the positive terminal C. 21 One end is connected to the negative terminal of the load simultaneously;

[0014] One end of the primary winding of the auxiliary single-phase transformer is connected to the neutral point A of the three-phase / five-phase transformer, and the other end of the primary winding of the auxiliary single-phase transformer is connected to the center tap B of the balancing reactor. The two ends of the secondary winding of the auxiliary single-phase transformer are connected to the positive terminal C and the negative terminal D of the input side of the active harmonic suppression auxiliary circuit, respectively.

[0015] One end E of the balancing reactor is connected to the capacitor C 11 The other end is connected, and the other end F of the balancing reactor is connected to the capacitor C. 21 The other end is connected;

[0016] The synchronous signal sampling circuit is used to acquire u a and u b and collect u a and u bAfter being sent to the fifth-harmonic triangular wave generation circuit, a fifth-harmonic triangular wave voltage signal is generated. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit is sent to the injection current setting circuit. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit is in the same frequency, phase and synchronous with the fifth-harmonic triangular wave voltage signal output by the secondary winding of the auxiliary single-phase transformer.

[0017] u a1 The voltage of phase a in the three-phase voltage input to the five-phase rectifier bridge of the three-phase / five-phase transformer;

[0018] u b1 The input voltage of phase b in the three-phase voltage of the three-phase rectifier bridge to the three-phase / five-phase transformer;

[0019] The load current sampling circuit is used to acquire the load current signal i flowing through the load. d and the load current signal i d Send to the injection current setting circuit;

[0020] Injection current setting circuit, used to input the received load current signal i d Multiplying the voltage signal by a fifth harmonic triangular wave generates a given current i. sref and the given current i sref The minuend input is fed into the subtractor;

[0021] The input current sampling circuit is used to acquire the current i output from the secondary winding of the auxiliary single-phase transformer. sf and its current i sf The subtrahend input is fed into the subtractor;

[0022] A subtractor is used to subtract from the received given current i sref With current i sf After comparison, the output difference result is sent to the hysteresis comparator; the hysteresis comparator is used to generate a control signal to drive the PWM signal drive circuit according to the received difference result and the preset ring width, so that the PWM signal drive circuit outputs a PWM drive signal to control the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit.

[0023] The preset hysteresis width is equal to the difference between the preset upper limit of the hysteresis boundary and the preset lower limit of the hysteresis boundary.

[0024] The second structure:

[0025] A 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, comprising a three-phase / five-phase transformer, a five-phase rectifier bridge, and an auxiliary single-phase pulse width adjustable current circuit;

[0026] The auxiliary single-phase pulse width adjustable current circuit includes a first auxiliary single-phase transformer, an active harmonic suppression auxiliary circuit, a second auxiliary single-phase transformer, a subtractor, a load current sampling circuit, a synchronization signal sampling circuit, a fifth-harmonic triangular wave generation circuit, an input current sampling circuit, an injection current setting circuit, a PWM signal driving circuit, a hysteresis comparator, and a capacitor C. 11 and capacitor C 21 ;

[0027] Three-phase / five-phase transformers are used to shift the three-phase voltage output from the power grid to generate a five-phase voltage with a phase difference of 72° between adjacent phases. This five-phase voltage serves as the input voltage of a five-phase rectifier bridge.

[0028] The positive output terminal of the five-phase rectifier bridge and capacitor C 11 One end of the rectifier bridge, the positive terminal Q of the active harmonic suppression auxiliary circuit output side, and the positive terminal of the load are connected simultaneously. The negative terminal of the five-phase rectifier bridge is connected to the negative terminal P of the active harmonic suppression auxiliary circuit output side, and the capacitor C is connected to the positive terminal C. 21 One end is connected to the negative terminal of the load simultaneously;

[0029] Capacitor C 11 The other end is connected to one end of the primary winding of the first auxiliary single-phase transformer. The other end of the primary winding of the first auxiliary single-phase transformer is connected to one end of the primary winding of the second auxiliary single-phase transformer at terminal B. Terminal B is connected to the neutral point A of the three-phase / five-phase transformer. The other end of the primary winding of the second auxiliary single-phase transformer is connected to capacitor C. 21 The other end is connected;

[0030] One end of the secondary winding of the first auxiliary single-phase transformer and one end of the secondary winding of the second auxiliary single-phase transformer serve as the positive terminal D and the negative terminal C of the input side of the active harmonic suppression auxiliary circuit, respectively; the other end of the secondary winding of the first auxiliary single-phase transformer is connected to the other end of the secondary winding of the second auxiliary single-phase transformer.

[0031] The synchronous signal sampling circuit is used to acquire u a and u b and collect u a and u b After being sent to the fifth-harmonic triangular wave generation circuit, a fifth-harmonic triangular wave voltage signal is generated. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit is sent to the injection current setting circuit. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit is in the same frequency, phase and synchronous with the fifth-harmonic triangular wave voltage signals output by the secondary windings of the first auxiliary single-phase transformer and the second auxiliary single-phase transformer.

[0032] u a1 This refers to phase a voltage, which is the three-phase voltage input from the three-phase / five-phase transformer to the five-phase rectifier bridge.

[0033] u b1 This refers to the phase b voltage among the three-phase voltages input from the three-phase / five-phase transformer to the five-phase rectifier bridge.

[0034] The load current sampling circuit is used to acquire the load current signal i flowing through the load. d and the load current signal i d Send to the injection current setting circuit;

[0035] Injection current setting circuit, used to input the received load current signal i d Multiplying the voltage signal by a fifth harmonic triangular wave generates a given current i. sref and the given current i sref The minuend input is fed into the subtractor;

[0036] The input current sampling circuit is used to collect the current i flowing through the input side of the active harmonic suppression auxiliary circuit. sf and its current i sf The subtrahend input is fed into the subtractor;

[0037] A subtractor is used to subtract from the received given current i sref With current i sf After comparison, the output difference result is sent to the hysteresis comparator; the hysteresis comparator is used to generate a control signal to drive the PWM signal drive circuit according to the received difference result and the preset ring width, so that the PWM signal drive circuit outputs a PWM drive signal to control the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit.

[0038] The preset hysteresis width is equal to the difference between the preset upper limit of the hysteresis boundary and the preset lower limit of the hysteresis boundary.

[0039] The beneficial effects of this invention are: This invention provides a 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, which reduces the input current harmonics of the 10-pulse rectifier by an order of magnitude under the premise of using a simple three-phase / five-phase transformer, so as to meet the requirements of industrial applications.

[0040] This invention introduces an auxiliary single-phase pulse width adjustable current circuit on the DC side of a 10-pulse rectifier. In specific applications, the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit is controlled according to the magnitude of the load current to control the conduction and turn-off of the switching transistor S1. Ultimately, the current flowing through the primary winding of the auxiliary single-phase transformer is a specific positive and negative symmetrical triangular wave current with an amplitude of twice the load current amplitude, or the current flowing through the conductor between terminal B and the neutral point A of the secondary winding of the three-phase / five-phase transformer is a specific positive and negative symmetrical triangular wave current with an amplitude of twice the load current amplitude and a frequency of five times the grid-side input voltage frequency. Then, according to the AC and DC side circuit relationship of the 10-pulse rectifier, the input current of the 10-pulse rectifier is corrected to an approximate sine wave with a THD of less than 5%.

[0041] When the grid-side input voltage or the voltage across the load changes, the sampled load current signal I... d The value of i changes accordingly, given a current i sref Accordingly, the operation of the switching transistor in the active harmonic suppression auxiliary circuit also changes, causing the input current of the active harmonic suppression auxiliary circuit to follow the given signal i of the injected current. sref The corresponding changes ensure effective suppression of harmonics in the input current of the 10-pulse rectifier.

[0042] This invention introduces a small-capacity (less than 5% of the output power) active harmonic suppression auxiliary circuit on the DC side of a 10-pulse rectifier, thereby reducing the THD of the input current to less than 5% to meet the requirements of harmonic standards such as IEEE 519.

[0043] This invention only requires controlling one switch in the active harmonic suppression auxiliary circuit to achieve a significant reduction in input current THD (below 5%). The circuit has the advantages of high efficiency, small size and easy control.

[0044] For the 10-pulse rectifier with the first structure, the present invention improves the energy utilization efficiency by extracting the harmonic energy of the 10-pulse rectifier from the secondary side of the auxiliary single-phase transformer and feeding it back to the load.

[0045] For the second type of 10-pulse rectifier, this invention improves energy utilization efficiency by extracting the harmonic energy of the 10-pulse rectifier from the secondary side of the active harmonic suppression auxiliary circuit and the second auxiliary single-phase transformer and feeding it back to the load. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit as described in Specific Embodiment 1; this structure is the first structure of the present invention.

[0047] Figure 2This is a schematic diagram of the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit as described in the second specific embodiment; this structure is the second structure of the present invention.

[0048] Figure 3 This is a schematic diagram of a single-phase Vienna rectifier circuit.

[0049] Figure 4 The graph shows the working process of the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit as described in Specific Implementation Method 5; where the horizontal axis represents time and the vertical axis represents current.

[0050] Figure 5 This is a schematic diagram of the operating state of a single-phase Vienna rectifier circuit during the time period from t0 to t1.

[0051] Figure 6 This is a schematic diagram of the operating state of a single-phase Vienna rectifier circuit during the time period from t1 to t2.

[0052] Figure 7 This is a schematic diagram of the operating state of a single-phase Vienna rectifier circuit during the time period from t3 to t4.

[0053] Figure 8 This is a schematic diagram of the operating state of a single-phase Vienna rectifier circuit during the time period from t4 to t5. Detailed Implementation

[0054] 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.

[0055] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0056] Specific Implementation Method 1: The following is combined with... Figure 1 This embodiment describes a 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, which includes a three-phase / five-phase transformer 1, a five-phase rectifier bridge 2, and an auxiliary single-phase pulse width adjustable current circuit.

[0057] The auxiliary single-phase pulse width adjustable current circuit includes: 3. auxiliary single-phase transformer; 4. active harmonic suppression auxiliary circuit; 5. balancing reactor; 6. subtractor; 7. load current sampling circuit; 9. synchronization signal sampling circuit; 10. fifth harmonic triangular wave generation circuit; 11. input current sampling circuit; 12. injection current setting circuit; 13. PWM signal driving circuit; 14. hysteresis comparator; and 15. capacitor C. 11 and capacitor C 21 ;

[0058] The three-phase / five-phase transformer 1 is used to shift the three-phase voltage output from the power grid to generate a five-phase voltage with a phase difference of 72° between adjacent phases. This five-phase voltage is used as the input voltage of the five-phase rectifier bridge 2.

[0059] The positive output terminal of the five-phase rectifier bridge 2 is connected to capacitor C. 11 One end of the active harmonic suppression auxiliary circuit 4, the positive terminal Q of the output side, and the positive terminal of the load 8 are connected simultaneously. The negative terminal of the five-phase rectifier bridge 2 is connected to the negative terminal P of the output side of the active harmonic suppression auxiliary circuit 4, and the capacitor C. 21 One end of the load is connected to the negative terminal of the load 8 simultaneously;

[0060] One end of the primary winding of the auxiliary single-phase transformer 3 is connected to the neutral point A of the three-phase / five-phase transformer 1, and the other end of the primary winding of the auxiliary single-phase transformer 3 is connected to the center tap B of the balancing reactor 5. The two ends of the secondary winding of the auxiliary single-phase transformer 3 are connected to the positive terminal C and the negative terminal D of the input side of the active harmonic suppression auxiliary circuit 4, respectively.

[0061] One end E of the balancing reactor 5 is connected to the capacitor C 11 The other end is connected, and the other end F of the balancing reactor 5 is connected to the capacitor C. 21 The other end is connected;

[0062] Synchronous signal sampling circuit 9 is used to acquire u a and u b and collect u a and u b After being sent to the fifth-harmonic triangular wave generation circuit 10, a fifth-harmonic triangular wave voltage signal is generated. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit 10 is sent to the injection current setting circuit 12. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit 10 is in the same frequency, phase and synchronous with the fifth-harmonic triangular wave voltage signal output by the secondary winding of the auxiliary single-phase transformer 3.

[0063] u a1 The voltage of phase a in the three-phase voltage input to the five-phase rectifier bridge 2 is the voltage of phase a in the three-phase voltage input to the three-phase / five-phase transformer 1.

[0064] u b1The input voltage of phase b in the three-phase voltage of the three-phase rectifier bridge 2 is given to the three-phase / five-phase transformer 1.

[0065] Load current sampling circuit 7 is used to acquire the load current signal i flowing through load 8. d and the load current signal i d Send to injection current setting circuit 12;

[0066] Injection current setting circuit 12 is used to input the received load current signal i d Multiplying the voltage signal by a fifth harmonic triangular wave generates a given current i. sref and the given current i sref The minuend is fed into the subtractor 6;

[0067] Input current sampling circuit 11 is used to collect the current i output from the secondary winding of the auxiliary single-phase transformer. sf and its current i sf The input is fed into the subtrahend input terminal of subtractor 6;

[0068] Subtractor 6 is used to subtract the received given current i sref With current i sf After comparison, the output difference result is sent to the hysteresis comparator 14; the hysteresis comparator 14 is used to generate a control signal to drive the PWM signal drive circuit 13 according to the received difference result and the preset ring width, so that the PWM signal drive circuit 13 outputs a PWM drive signal to control the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit 4.

[0069] The preset hysteresis width is equal to the difference between the preset upper limit of the hysteresis boundary and the preset lower limit of the hysteresis boundary.

[0070] In this embodiment, the PWM signal driving circuit 13 outputs a PWM driving signal to control the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit 4, thereby controlling the turn-on and turn-off of the switching transistor S1. When the grid-side input voltage or the voltage flowing through the load 8 changes, the sampled load current signal i d The value of i changes accordingly, given a current i sref Accordingly, the operation of the switching transistor in the active harmonic suppression auxiliary circuit 4 also changes, causing the input current of the active harmonic suppression auxiliary circuit 4 to follow the given signal i of the injected current. sref The corresponding changes ensure effective suppression of harmonics in the input current of the 10-pulse rectifier.

[0071] In practical applications, the hysteresis comparator 14 can be controlled by a PI controller or a predictive control method.

[0072] The frequency of the output voltage of the auxiliary single-phase transformer 3 is 5 times that of the three-phase voltage output from the power grid, and the shape of the output voltage of the auxiliary single-phase transformer 3 is an approximately symmetrical triangular wave.

[0073] Specific Implementation Method Two: The following is combined with... Figure 1 This embodiment describes a 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, which includes a three-phase / five-phase transformer 1, a five-phase rectifier bridge 2, and an auxiliary single-phase pulse width adjustable current circuit.

[0074] The auxiliary single-phase pulse width adjustable current circuit includes a first auxiliary single-phase transformer 3, an active harmonic suppression auxiliary circuit 4, a second auxiliary single-phase transformer 5, a subtractor 6, a load current sampling circuit 7, a synchronization signal sampling circuit 9, a fifth-harmonic triangular wave generation circuit 10, an input current sampling circuit 11, an injection current setting circuit 12, a PWM signal driving circuit 13, a hysteresis comparator 14, and a capacitor C. 11 and capacitor C 21 ;

[0075] The three-phase / five-phase transformer 1 is used to shift the three-phase voltage output from the power grid to generate a five-phase voltage with a phase difference of 72° between adjacent phases. This five-phase voltage is used as the input voltage of the five-phase rectifier bridge 2.

[0076] The positive output terminal of the five-phase rectifier bridge 2 is connected to capacitor C. 11 One end of the active harmonic suppression auxiliary circuit 4, the positive terminal Q of the output side, and the positive terminal of the load 8 are connected simultaneously. The negative terminal of the five-phase rectifier bridge 2 is connected to the negative terminal P of the output side of the active harmonic suppression auxiliary circuit 4, and the capacitor C. 21 One end of the load is connected to the negative terminal of the load 8 simultaneously;

[0077] Capacitor C 11 The other end is connected to one end of the primary winding of the first auxiliary single-phase transformer 3. The other end of the primary winding of the first auxiliary single-phase transformer 3 is connected to one end of the primary winding of the second auxiliary single-phase transformer 5 at terminal point B. Terminal point B is connected to the neutral point A of the three-phase / five-phase transformer 1. The other end of the primary winding of the second auxiliary single-phase transformer 5 is connected to capacitor C. 21 The other end is connected;

[0078] One end of the secondary winding of the first auxiliary single-phase transformer 3 and one end of the secondary winding of the second auxiliary single-phase transformer 5 serve as the positive terminal D and the negative terminal C of the input side of the active harmonic suppression auxiliary circuit 4, respectively; the other end of the secondary winding of the first auxiliary single-phase transformer 3 is connected to the other end of the secondary winding of the second auxiliary single-phase transformer 5.

[0079] Synchronous signal sampling circuit 9 is used to acquire u a and ub and collect u a and u b After being sent to the fifth-harmonic triangular wave generation circuit 10, a fifth-harmonic triangular wave voltage signal is generated. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit 10 is sent to the injection current setting circuit 12. The fifth-harmonic triangular wave voltage signal generated by the fifth-harmonic triangular wave generation circuit 10 is in the same frequency, phase and synchronous with the fifth-harmonic triangular wave voltage signals output by the secondary windings of the first auxiliary single-phase transformer 3 and the second auxiliary single-phase transformer 5.

[0080] u a1 The voltage of phase a in the three-phase voltage input from the three-phase / five-phase transformer 1 to the five-phase rectifier bridge 2;

[0081] u b1 This refers to the phase b voltage among the three-phase voltages input from the three-phase / five-phase transformer 1 to the five-phase rectifier bridge 2.

[0082] Load current sampling circuit 7 is used to acquire the load current signal i flowing through load 8. d and the load current signal i d Send to injection current setting circuit 12;

[0083] Injection current setting circuit 12 is used to input the received load current signal i d Multiplying the voltage signal by a fifth harmonic triangular wave generates a given current i. sref and the given current i sref The minuend is fed into the subtractor 6;

[0084] Input current sampling circuit 11 is used to collect the current i flowing through the input side of active harmonic suppression auxiliary circuit 4. sf and its current i sf The input is fed into the subtrahend input terminal of subtractor 6;

[0085] Subtractor 6 is used to subtract the received given current i sref With current i sf After comparison, the output difference result is sent to the hysteresis comparator 14; the hysteresis comparator 14 is used to generate a control signal to drive the PWM signal drive circuit 13 according to the received difference result and the preset ring width, so that the PWM signal drive circuit 13 outputs a PWM drive signal to control the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit 4.

[0086] The preset hysteresis width is equal to the difference between the preset upper limit of the hysteresis boundary and the preset lower limit of the hysteresis boundary.

[0087] In this embodiment, the PWM signal driving circuit 13 outputs a PWM driving signal to control the gate of the switching transistor S1 in the active harmonic suppression auxiliary circuit 4, thereby controlling the conduction and turn-off of the switching transistor S1. When the grid-side input voltage or the current flowing through the load 8 changes, the sampled load current signal i d The value of i changes accordingly, given a current i sref Accordingly, the operation of the switching transistor in the active harmonic suppression auxiliary circuit 4 also changes, causing the input current of the active harmonic suppression auxiliary circuit 4 to follow the given signal i of the injected current. sref The corresponding changes ensure effective suppression of harmonics in the input current of the 10-pulse rectifier.

[0088] In practical applications, the hysteresis comparator 14 can be controlled by a PI controller or a predictive control method.

[0089] The frequency of the output voltage between one end of the secondary winding of the first auxiliary single-phase transformer 3 and one end of the secondary winding of the second auxiliary single-phase transformer 5 is 5 times the frequency of the three-phase voltage output from the power grid, and its output voltage shape is an approximately symmetrical triangular wave.

[0090] Specific Implementation Method Three: The following is combined with... Figure 1 and Figure 2 This embodiment differs from the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit described in specific embodiments one or two in that...

[0091] When the difference received by the hysteresis comparator 14 is greater than or equal to its preset ring width, the PWM signal drive circuit 13 controls the switch S1 in the active harmonic suppression auxiliary circuit 4 to turn off.

[0092] When the difference received by the hysteresis comparator 14 is less than its preset ring width, the PWM signal drive circuit 13 controls the switch S1 in the active harmonic suppression auxiliary circuit 4 to turn on.

[0093] Specific Implementation Method Four: The following is combined with... Figure 1 and Figure 2 This embodiment differs from the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit described in specific embodiment one or two in that the active harmonic suppression auxiliary circuit 4 is implemented using a single-phase Vienna rectifier circuit.

[0094] In this preferred embodiment, the active harmonic suppression auxiliary circuit 4 can also be other controllable rectifier circuits that can generate suitable triangular wave current and operate at unity power factor, including but not limited to: single-phase PWM rectifier circuits and APFC type rectifier circuits.

[0095] Specific Implementation Method Five: The following is combined with... Figure 3 This embodiment differs from the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit described in Embodiment 4 in that the single-phase Vienna rectifier circuit includes an inductor L. s Switch S1, diodes D1 to D6, capacitor C 11 and capacitor C 12 ;

[0096] Inductor L s One end serves as the negative input terminal D of the active harmonic suppression auxiliary circuit 4;

[0097] Inductor L s The other end is connected to the anode of diode D1 and the cathode of diode D3 at the same time. The cathode of diode D1 is connected to the cathode of diode D2, the anode of diode D5 and the anode of switch S1 at the same time.

[0098] The cathode of diode D5 and capacitor C 11 After one end is connected, it serves as the positive terminal Q on the output side of the active harmonic suppression auxiliary circuit 4;

[0099] The anode of diode D3 is connected to the anode of diode D4, the cathode of switching transistor S1, and the cathode of diode D6 simultaneously.

[0100] The anode of diode D6 and capacitor C 12 After one end is connected, it serves as the negative terminal P on the output side of the active harmonic suppression auxiliary circuit 4;

[0101] Capacitor C 11 The other end is connected to capacitor C 12 The other end, after the anode of diode D2 and the cathode of diode D4 are connected simultaneously, serves as the positive terminal C of the active harmonic suppression auxiliary circuit 4.

[0102] In this embodiment, the switching transistor S1 can also be a MOSFET.

[0103] Specific Implementation Method Six: The following is combined with... Figures 4 to 8 This embodiment differs from the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit described in Specific Embodiment Five in that the single-phase Vienna rectifier circuit includes the following four operating modes, as detailed below:

[0104] Working Mode I: Combination Figure 4 and Figure 5 To explain, at time t0, diode D2, switching transistor S1, and diode D3 begin to conduct;

[0105] During the time interval from t0 to t1, current flows through inductor L scurrent i sf Reverse flow, specifically: current i sf The current flows sequentially through diode D2, switch S1, diode D3, and inductor L. s And the current i sf The amplitude increases linearly, and the capacitance C 11 and capacitor C 12 Power supply to load 8;

[0106] At time t1, the current i sf When the preset hysteresis boundary upper limit is reached, switch S1 is turned off, and this working mode ends; t1 > t0;

[0107] Working Mode II: Combining Figure 4 and Figure 6 To explain, at time t1, after switch S1 is turned off, the current i sf The current still flows in the reverse direction and freewheels through diode D6 and the triple diode D3;

[0108] During the time period from t1 to t2, the current i sf Linear decrease, inductance L s and voltage u sf Together for capacitor C 12 Charge and supply power to load 8;

[0109] At time t2, the current i sf Once the preset lower limit of the hysteresis boundary is reached, the switch S1 begins to conduct, and this operating mode ends; t2 > t1;

[0110] Among them, u sf The output voltage between the positive terminal C and the negative terminal D of the input side of the active harmonic suppression auxiliary circuit 4;

[0111] Working Mode III: Combining Figure 4 and Figure 7 To explain, at time t3, diodes D1 and D4 and switch S1 begin to conduct;

[0112] During the time period from t3 to t4, current flows through inductor L s current i sf Forward flow, specifically: the current i output from the negative terminal D of the input side of the active harmonic suppression auxiliary circuit 4. sf The current flows sequentially through inductor L s Diode D1, switch S1, and diode D4, and the current i sf The capacitance C increases linearly in the positive direction. 11 and capacitor C 12 Power supply to load 8;

[0113] At time t4, the current i sfWhen the preset hysteresis boundary upper limit is reached, switch S1 is turned off, and this working mode ends; t4 > t3;

[0114] Working Mode IV: Combination Figure 4 and Figure 8 To explain, at time t4, after switch S1 is turned off, the current i sf The current i is still flowing in the forward direction. sf The current freewheels through diodes D1 and D5;

[0115] During the period from t4 to t5, the current i sf Linear decrease, inductance L s and voltage u sf Together for capacitor C 11 Charge and supply power to load 8;

[0116] At time t5, the current i sf Once the preset lower limit of the hysteresis boundary is reached, the switch S1 starts to conduct, and this operating mode ends.

[0117] Among them, u sf The output voltage between the positive terminal C and the negative terminal D of the input side of the active harmonic suppression auxiliary circuit 4; t5 > t4.

[0118] Specific Implementation Method Seven: The following is combined with... Figure 3 This embodiment differs from the 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit described in Specific Embodiment Six in that, among the four operating modes of the single-phase Vienna rectifier circuit,

[0119] Current i sf During the forward flow, work mode III and work mode IV are carried out alternately;

[0120] Current i sf During reverse flow, operating mode I and operating mode II alternate.

[0121] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, characterized in that, The auxiliary single-phase pulse width adjustable current circuit comprises a three-phase / five-phase transformer (1), a five-phase rectifier bridge (2) and an auxiliary single-phase pulse width adjustable current circuit. The auxiliary single-phase pulse width adjustable current circuit includes an auxiliary single-phase transformer (3), an active harmonic suppression auxiliary circuit (4), a balanced reactor (5), a subtractor (6), a load current sampling circuit (7), a synchronization signal sampling circuit (9), a five times frequency triangular wave generating circuit (10), an input current sampling circuit (11), an injected current setting circuit (12), a PWM signal driving circuit (13), a hysteresis comparator (14), a capacitor C 11 and a capacitor C 21 ; The three-phase / five-phase transformer (1) is used for phase-shifting three-phase voltage output by a power grid to generate five-phase voltage with a phase difference of 72° between adjacent two phases, which is used as input voltage of the five-phase rectifier bridge (2). The positive polarity output terminal of the five-phase rectifier bridge (2) is connected with one end of the capacitor C 11 , the positive polarity output terminal of the active harmonic suppression auxiliary circuit (4) and the positive polarity terminal of the load (8). The negative polarity output terminal of the five-phase rectifier bridge (2) is connected with the negative polarity output terminal of the active harmonic suppression auxiliary circuit (4), one end of the capacitor C 21 and the negative polarity terminal of the load (8). One end of a primary winding of the auxiliary single-phase transformer (3) is connected with a neutral point A of the three-phase / five-phase transformer (1), the other end of the primary winding of the auxiliary single-phase transformer (3) is connected with a center tap B of the balancing reactor (5), and two ends of a secondary winding of the auxiliary single-phase transformer (3) are respectively connected with an input side positive polarity end C and an input side negative polarity end D of the active harmonic suppression auxiliary circuit (4). One end E of the balancing reactor (5) is connected to one end of the capacitor C 11 The other end F of the balancing reactor (5) is connected to the other end of the capacitor C 21 The other end F of the balancing reactor (5) is connected to the other end of the capacitor C The synchronous signal sampling circuit (9) is used for collecting u a and u b The collected u a and u b are sent to the five times frequency triangular wave generating circuit (10) to generate a five times frequency triangular wave voltage signal, which is sent to the injection current setting circuit (12); wherein the five times frequency triangular wave voltage signal generated by the five times frequency triangular wave generating circuit (10) is the same frequency, same phase and synchronous with the five times frequency triangular wave voltage signal output by the secondary winding of the auxiliary single-phase transformer (3). u a1 a phase voltage of the three-phase voltage input to the five-phase rectifier bridge (2) for the three-phase / five-phase transformer (1); u b1 a phase voltage of the three-phase voltage input to the five-phase rectifier bridge (2) for a three-phase / five-phase transformer (1); The load current sampling circuit (7) is used to collect the load current signal i flowing through the load (8) d and send the load current signal i d to the injection current setting circuit (12); The injected current setting circuit (12) is used to set the received load current signal i d and the five times frequency triangular wave voltage signal, to generate the setting current i sref and the five times frequency triangular wave voltage signal, to generate the setting current i sref into the minuend input terminal of the subtractor (6); The input current sampling circuit (11) is used to collect the current i output from the secondary winding of the auxiliary single-phase transformer (3). sf and its current i sf The subtrahend input is fed into the subtractor (6); a subtracter (6) for subtracting the given current i sref from the current i sf After comparison, the output difference result is sent to a hysteresis comparator (14); the hysteresis comparator (14) is used to generate a control signal to drive and control the PWM signal driving circuit (13) according to the received difference result and a preset hysteresis width, so that the PWM signal driving circuit (13) outputs a PWM driving signal to control the gate of the switch S1 in the active harmonic suppression auxiliary circuit (4); The preset ring width is equal to a difference between the preset upper limit of the hysteresis loop boundary and the preset lower limit of the hysteresis loop boundary.

2. A 10-pulse rectifier with an auxiliary single-phase pulse width adjustable current circuit, characterized by, The auxiliary single-phase pulse width adjustable current circuit comprises a three-phase / five-phase transformer (1), a five-phase rectifier bridge (2) and an auxiliary single-phase pulse width adjustable current circuit. The auxiliary single-phase pulse width adjustable current circuit comprises a first auxiliary single-phase transformer (3), an active harmonic suppression auxiliary circuit (4), a second auxiliary single-phase transformer (5), a subtractor (6), a load current sampling circuit (7), a synchronization signal sampling circuit (9), a five times frequency triangular wave generating circuit (10), an input current sampling circuit (11), an injected current setting circuit (12), a PWM signal driving circuit (13), a hysteresis comparator (14), a capacitor C 11 and a capacitor C 21 ; The three-phase / five-phase transformer (1) is used for phase-shifting three-phase voltage output by a power grid to generate five-phase voltage with a phase difference of 72° between adjacent two phases, which is used as input voltage of the five-phase rectifier bridge (2). The positive polarity output terminal of the five-phase rectifier bridge (2) is connected with one end of the capacitor C 11 , the positive polarity output terminal of the active harmonic suppression auxiliary circuit (4) and the positive polarity terminal of the load (8). The negative polarity output terminal of the five-phase rectifier bridge (2) is connected with the negative polarity output terminal of the active harmonic suppression auxiliary circuit (4), one end of the capacitor C 21 and the negative polarity terminal of the load (8). capacitor C 11 the other end of the primary winding of the first auxiliary single-phase transformer (3) is connected to the end point B, which is connected to the neutral point A of the three-phase / five-phase transformer (1), the other end of the primary winding of the second auxiliary single-phase transformer (5) is connected to the other end of the capacitor C 21 ​ One end of a secondary winding of the first auxiliary single-phase transformer (3) and one end of a secondary winding of the second auxiliary single-phase transformer (5) are respectively used as an input side positive polarity end D and an input side negative polarity end C of the active harmonic suppression auxiliary circuit (4), and the other end of the secondary winding of the first auxiliary single-phase transformer (3) is connected with the other end of the secondary winding of the second auxiliary single-phase transformer (5). The synchronous signal sampling circuit (9) is used for collecting u a and u b The collected u a and u b are sent to the five times frequency triangular wave generating circuit (10) to generate a five times frequency triangular wave voltage signal, and the five times frequency triangular wave voltage signal generated by the five times frequency triangular wave generating circuit (10) is sent to the injection current setting circuit (12); wherein the five times frequency triangular wave voltage signal generated by the five times frequency triangular wave generating circuit (10) is the same frequency, the same phase and synchronous with the five times frequency triangular wave voltage signal output by the secondary side winding of the first auxiliary single-phase transformer (3) and the second auxiliary single-phase transformer (5). u a1 is the a-phase voltage of the three-phase voltage input from the three-phase / five-phase transformer (1) into the five-phase rectifier bridge (2); u b1 is the b-phase voltage in the three-phase voltage input from the three-phase / five-phase transformer (1) to the five-phase rectifier bridge (2); The load current sampling circuit (7) is used to collect the load current signal i flowing through the load (8) d and send the load current signal i d to the injection current setting circuit (12); The injected current setting circuit (12) is used to set the received load current signal i d and the five times frequency triangular wave voltage signal, to generate the setting current i sref and the five times frequency triangular wave voltage signal, to generate the setting current i sref into the minuend input terminal of the subtractor (6); An input current sampling circuit (11) is used to collect the current i flowing through the input side of the active harmonic suppression auxiliary circuit (4) sf and sends it to the minuend input of the subtractor (6) sf ; a subtracter (6) for subtracting the given current i sref from the current i sf After comparison, the output difference result is sent to a hysteresis comparator (14); the hysteresis comparator (14) is used to generate a control signal to drive and control the PWM signal driving circuit (13) according to the received difference result and a preset hysteresis width, so that the PWM signal driving circuit (13) outputs a PWM driving signal to control the gate of the switch S1 in the active harmonic suppression auxiliary circuit (4); The preset ring width is equal to a difference between the preset upper limit of the hysteresis loop boundary and the preset lower limit of the hysteresis loop boundary.

3. The 10-pulse rectifier with the auxiliary single-phase pulse width adjustable current circuit according to claim 1 or 2, characterized in that, When the difference value received by the hysteresis comparator (14) is greater than or equal to the preset ring width, the PWM signal driving circuit (13) controls the switch tube S1 in the active harmonic suppression auxiliary circuit (4) to be turned off; When the difference value received by the hysteresis comparator (14) is less than the preset ring width, the PWM signal driving circuit (13) controls the switch tube S1 in the active harmonic suppression auxiliary circuit (4) to be turned on.

4. The 10-pulse rectifier of the band-aid single-phase pulse width adjustable current circuit according to claim 1 or 2, characterized in that, The active harmonic suppression auxiliary circuit (4) is realized by using a single-phase Vienna rectifier circuit.

5. The 10-pulse rectifier with auxiliary single-phase pulse width adjustable current circuit according to claim 4, characterized in that, The single-phase Vienna rectifier circuit comprises an inductor L s , a switch S1, diodes D1 to D6, a capacitor C 11 and a capacitor C 12 ​ inductor L s one end as a negative polarity input terminal D of the active harmonic suppression auxiliary circuit (4); inductor L s the other end of the inductor L is connected to the anode of diode D1 and the cathode of diode D3, the cathode of diode D1 is connected to the cathode of diode D2, the anode of diode D5 and the anode of switch S1 simultaneously; The cathode of diode D5 is connected to one end of capacitor C 11 , and outputs a positive polarity terminal Q on the output side of the active harmonic suppression auxiliary circuit (4). The anode of the diode D3 is connected with the anode of the diode D4, the cathode of the switch tube S1 and the cathode of the diode D6. The anode of diode D6 is connected to one end of capacitor C 12 as an active harmonic suppression auxiliary circuit (4) output side negative polarity terminal P; The other end of the capacitor C 11 is connected to the other end of the capacitor C 12 , the anode of the diode D2 and the cathode of the diode D4, and functions as the positive polarity terminal C of the active harmonic suppression auxiliary circuit (4).

6. The 10-pulse rectifier with auxiliary single-phase pulse width adjustable current circuit according to claim 5, characterized in that, The single-phase Vienna rectifier circuit comprises the following four working modes, and the details are as follows: Working mode I: at t0 moment, the diode D2, the switch tube S1 and the diode D3 start to be turned on; During the period from t0 to t1, the current i s flowing through the inductor L sf flows in the reverse direction, specifically: the current i sf flows through the diode D2, the switch S1, the diode D3 and the inductor L s in turn, and the amplitude of the current i sf increases linearly, the capacitor C 11 and the capacitor C 12 supply power to the load (8); At time t1, the current i sf The preset upper limit of the hysteresis loop is reached, the switch tube S1 is turned off, and the working mode ends; t1>t0. Working mode II: at t1 moment, after switch tube S1 is turned off, current i sf Still flows reversely, and continues to flow through diode D6 and tri-diode D3; During the period t1 to t2, the current i sf is linearly decreasing, the inductance L s and the voltage u sf together charge the capacitor C 12 and supply the load (8) At time t2, the current i sf The preset hysteresis lower limit is reached, and the switch tube S1 starts to conduct, and the working mode ends; t2>t1. wherein u sf is the output voltage between the positive input side end C and the negative input side end D of the active harmonic suppression auxiliary circuit (4); Working mode III: at t3 moment, the diode D1, the diode D4 and the switch tube S1 start to be turned on; During the period of t3 to t4, the current i s flows through the inductor L sf in a forward direction, specifically: the current i sf output from the positive polarity end D of the input side of the active harmonic suppression auxiliary circuit (4) successively flows through the inductor L s , the diode D1, the switch tube S1 and the diode D4, and the current i sf increases linearly in a forward direction, the capacitor C 11 and the capacitor C 12 supply power to the load (8); At time t4, the current i sf The preset upper limit of the hysteresis loop is reached, the switch S1 is turned off, and the working mode ends; t4>t3. Working mode IV: at t4, after the switch S1 is turned off, the current i sf is still flowing forward, the current i sf continues to flow through the diode D1 and the diode D5; In the interval t4 to t5 the current i sf decreases linearly, the inductance L s and the voltage u sf together charge the capacitance C 11 and supply the load (8) At the time t5, the current i sf The preset hysteresis lower limit is reached, and the switch tube S1 starts to conduct, and the working mode ends. wherein u sf is the output voltage between the positive input side end C and the negative input side end D of the active harmonic suppression auxiliary circuit (4); t5 > t4.

7. The 10-pulse rectifier with auxiliary single-phase pulse width adjustable current circuit according to claim 6, characterized in that, In the four working modes of the single-phase Vienna rectifier circuit, Current i sf During forward flow, operating mode III and operating mode IV are alternated. Current i sf During the reverse flow, the working mode I and the working mode II are alternately performed.

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