Traction system circuit with double inversion modules

Abstract

The utility model discloses a traction system circuit with double inversion modules. The traction system circuit comprises a charging and discharging module, a current inversion module and a motor module, the charging and discharging module comprises a charging and discharging resistor and a fixed discharging resistor; the current inversion module comprises a first current inversion module and a second current inversion module which are connected in parallel; the two ends of the current inversion module are provided with sensors, and the main circuit is further provided with a sensor for measuring the voltage of a power grid. According to the traction system circuit with the double inverter modules, through the design of the double inverter modules, the system can optimize power distribution, reduce the load of a single inverter module, improve the inversion efficiency and reliability and reduce the temperature of the system; in addition, a charging and discharging resistor and a fixed discharging resistor are arranged, current changes are controlled, a capacitor is prevented from storing residual charges, safety and stability of the circuit are ensured, and the detection precision at low speed is improved by adopting a Hall sensor.

Description

Technical Field

[0001] The utility model relates to a traction system circuit with a dual-inverter module, belonging to the technical field of power electronics. Background Art

[0002] The traction system with a single traction inverter is widely used in fields such as electric traction and rail transit. Its core function is to convert direct current electrical energy into controllable alternating current electrical energy to drive the traction motor.

[0003] In the current single-inverter traction system circuit, the inverter, as a key component of the traction system, works by high-speed switching of power electronic devices (such as IGBTs or MOSFETs) to form an alternating current output with a specific frequency and amplitude to meet the requirements of the traction motor. However, when the current inverter operates at high power, the circuit traction load of a single inverter module is too high, a large amount of heat is generated in the circuit, and the heat dissipation design is insufficient, resulting in overheating of components, reduced efficiency, and shortened lifespan. In addition, during the conversion process, the inverter needs to monitor the entire circuit in real time, and there are certain power losses in the circuit, including switching losses and conduction losses, which limit the efficiency and power density of the system. The current magnetoelectric sensing has low measurement accuracy at low speeds.

[0004] Therefore, it is necessary to design a new traction system circuit with a dual-inverter module, which can relieve the load of the circuit system, optimize the heat dissipation design, and provide more stable and accurate circuit information feedback, so as to meet the requirements of the rail transit system for optimized load, optimized heat dissipation, and feedback accuracy. Summary of the Utility Model

[0005] Therefore, the purpose of the utility model is to provide a traction system circuit with a dual-inverter module that optimizes the circuit load and heat dissipation.

[0006] To achieve the above object, a traction system circuit of a dual-inverter module of the present utility model includes a charge and discharge module, a current inverter module, and a motor module; the charge and discharge module includes a charge and discharge resistor CHRe and a fixed discharge resistor, the output end of the charge and discharge resistor CHRe is connected to the input end of the fixed discharge resistor, the input end of the fixed discharge resistor is also connected to the input end of the current inverter module, and the output end of the fixed discharge resistor is connected to the output end of the current inverter module; the current inverter module includes a first current inverter module INVMK1 and a second current inverter module INVMK2, and the two inverter modules are connected in parallel; the motor module includes a first motor group and a second motor group, the first current inverter module INVMK1 is connected to the input end of the first motor group, and the second current inverter module INVMK2 is connected to the input end of the second motor group; a second sensor DCPT2 is provided at both ends of the current inverter module, and both ends of the second sensor DCPT2 are connected to both ends of the current inverter module. A first sensor DCPT1 for measuring the grid voltage is also provided in the main circuit. One end of the first sensor DCPT1 is connected to the charge and discharge module, and the other end is connected to the current inverter module.

[0007] The charge and discharge module is further provided with a first electric control switch CHB and a second electric control switch LB. When the charge and discharge resistor CHRe is charging, the first electric control switch CHB is closed and the second electric control switch LB is opened; when the charge and discharge resistor CHRe is discharging, the first electric control switch CHB is opened and the second electric control switch LB is closed.

[0008] The charge and discharge module is further provided with a filter reactor FL. The output end of the charge and discharge resistor is connected to the input end of the filter reactor FL, and the input end of the fixed discharge resistor is connected to the output end of the filter reactor FL.

[0009] The circuit is further provided with a main disconnect switch MS, a main fuse MF, and a high-speed circuit breaker HB connected in series in sequence; the circuit is provided with a positive line current sensor DCCT1. One end of the positive line current sensor DCCT1 is connected to the high-speed circuit breaker HB, and the other end is connected to the charge and discharge module.

[0010] Both the first current inverter module INVMK1 and the second current inverter module INVMK2 include a capacitor and an inverter unit connected in parallel; the inverter unit includes a chopper, a diode, and a plurality of inverters; among them, the plurality of inverters form U, V, and W three-phase inverter branches, and each phase inverter branch includes two inverters connected in series; the chopper and the diode are connected in series and then connected in parallel with the three-phase inverter branch.

[0011] The current inversion module is also provided with a first chopping current sensor BCT1 and a second chopping current sensor BCT2. The first chopping current sensor BCT1 is used to measure the chopping current of the first current inversion module INVMK1. The output end of the first chopping current sensor BCT1 is connected to the input end of the first wave resistance BR1, and the input end of the first chopping current sensor BCT1 is connected between the output end of the first chopper BCH1 and the input end of the first diode BRD1. The second chopping current sensor BCT2 is used to measure the chopping current of the second current inversion module INVMK2. The output end of the second chopping current sensor BCT2 is connected to the input end of the second wave resistance BR2, and the input end of the second chopping current sensor BCT2 is connected between the output end of the second chopper BCH2 and the input end of the second diode BRD2.

[0012] The motor module includes a plurality of inverter current sensors for monitoring the inverter current of the first motor group and the second motor group. The first inverter current sensor CTU1 and the second inverter current sensor CTV1 are connected to the first current inversion module INVMK1 to monitor the inverter current input to the U and V phases of the first motor group. The third inverter current sensor CTU2 and the fourth inverter current sensor CTV2 are connected to the second current inversion module INVMK2 to monitor the inverter current input to the U and V phases of the second motor group.

[0013] The fixed discharge resistor is connected in parallel with the current inversion module. The fixed discharge resistor includes a plurality of discharge resistors. The first discharge resistor R1 and the second discharge resistor R2 are connected in series, and the third discharge resistor R3 and the fourth discharge resistor R4 are connected in series, and then these two series units are connected in parallel.

[0014] The charge and discharge module is provided with a maintenance switch DS. One end of the maintenance switch DS is connected to the output end of the first sensor DCPT1, and the other end is connected to the input end of the charge and discharge resistor CHRe.

[0015] The circuit is also provided with a negative line current sensor DCCT2. The input end is connected to the output end of the first sensor DCPT1, and the output end of the negative line current sensor DCCT2 is grounded.

[0016] With the above technical solution, the traction system circuit of the dual-inverter module of the present utility model can better distribute power output by setting the structure of the dual-inverter module, reduce the load pressure on a single inverter module, improve the inversion efficiency and reliability, and effectively reduce the temperature of the traction system. In addition, a charge-discharge resistor and a fixed discharge resistor are provided. The charge-discharge resistor prevents the circuit from being impacted by excessive transient current, controls the current change, and ensures the safety and stability of the circuit. The fixed discharge resistor ensures that the capacitor does not store residual charges, prevents electric shock and other potential dangers, and maintains the stability of the circuit. At the same time, a Hall sensor is also adopted to improve the detection accuracy of the circuit at low speeds. Brief Description of the Drawings

[0017] Figure 1 This is the circuit diagram of the present utility model. Detailed Embodiment

[0018] The present utility model will be further described in detail below with reference to the drawings and specific embodiments.

[0019] As Figure 1 shown, the traction system circuit of the dual-inverter module of the present utility model includes a charge-discharge module 1, a current inversion module 2, and a motor module. The charge-discharge module 1 includes a charge-discharge resistor CHRe and a fixed discharge resistor 3. The output end of the charge-discharge resistor CHRe is connected to the input end of the fixed discharge resistor 3. The input end of the fixed discharge resistor 3 is also connected to the input end of the current inversion module 2, and the output end of the fixed discharge resistor 3 is connected to the output end of the current inversion module 2. The current inversion module 2 includes a first current inversion module INVMK1 and a second current inversion module INVMK2, and the two inversion modules are connected in parallel. The motor module includes a first motor group 4 and a second motor group 5. The first current inversion module INVMK1 is connected to the input end of the first motor group 4, and the second current inversion module INVMK2 is connected to the input end of the second motor group 5. A second sensor DCPT2 is provided at both ends of the current inversion module 2, and both ends of the second sensor DCPT2 are connected to both ends of the current inversion module 2. A first sensor DCPT1 for measuring the grid voltage is also provided in the main circuit. One end of the first sensor DCPT1 is connected to the charge-discharge module 1, and the other end is connected to the current inversion module 2.

[0020] The charge-discharge module 1 is also provided with a first electric control switch CHB and a second electric control switch LB. When the charge-discharge resistor CHRe is charging, the first electric control switch CHB is closed and the second electric control switch LB is opened. When the charge-discharge resistor CHRe is discharging, the first electric control switch CHB is opened and the second electric control switch LB is closed. By setting the charge-discharge resistor CHRe, it is possible to prevent the circuit from being impacted by excessive transient current and thus control the current change.

[0021] The charging and discharging module 1 is also provided with a filter reactor FL. The output end of the charging and discharging resistor is connected to the input end of the filter reactor FL, and the input end of the fixed discharge resistor 3 is connected to the output end of the filter reactor FL. The three are in series connection, which is used to reduce the influence of high-frequency harmonics on electrical equipment, extend the service life of the equipment, and maintain the stable output of the power supply. In addition, after the filter reactor FL is connected in series with a capacitor, it can not only effectively absorb power grid harmonics, but also improve the power factor of the system, which plays a great role in the safe operation of the system.

[0022] The circuit is also provided with a main disconnector MS, a main fuse MF, and a high-speed circuit breaker HB, which are connected in series in sequence. In addition, the circuit is provided with a bus disconnector BS, and the circuit is provided with a bus disconnector BS in parallel with the main disconnector MS for isolating the bus.

[0023] The circuit is provided with a positive line current sensor DCCT1. One end of the positive line current sensor DCCT1 is connected to the high-speed circuit breaker HB, and the other end is connected to the charging and discharging module 1 for measuring the positive line current.

[0024] The first current inversion module INVMK1 includes a first capacitor FC1 and a first inversion module 6. The first capacitor FC1 and the first inversion module 6 are connected in parallel; the first inversion module 6 includes a first chopper BCH1, a first diode BRD1, and multiple inverters. The first chopper BCH1 and the first diode BRD1 are connected in series. The first inverter IG1U is connected in series with the second inverter IG2U, the third inverter IG1V is connected in series with the fourth inverter IG2V, and the fifth inverter IG1W is connected in series with the sixth inverter IG2W. Then these four series units are connected in parallel in pairs; the second current inversion module INVMK2 includes a second capacitor FC2 and a second inversion module 7. The second capacitor FC2 and the second inversion module 7 are connected in parallel; the second inversion module 7 includes a second chopper BCH2, a second diode BRD2, and multiple inverters. The second chopper BCH2 and the second diode BRD2 are connected in series. The seventh inverter IG1U is connected in series with the eighth inverter IG2U, the ninth inverter IG1V is connected in series with the tenth inverter IG2V, and the eleventh inverter IG1W is connected in series with the twelfth inverter IG2W. Then these four series units are connected in parallel in pairs. The two inversion modules are connected in parallel, which improves the total output power of the system, enhances the reliability and redundancy, and improves the system fault tolerance; in addition, load sharing reduces the load pressure and loss of a single module, the system temperature decreases, and the service life of the module is extended.

[0025] The current inversion module 2 is also provided with a first chopping current sensor BCT1 and a second chopping current sensor BCT2. The first chopping current sensor BCT1 is used to measure the chopping current of the first current inversion module INVMK1. The output end of the first chopping current sensor BCT1 is connected to the input end of the first wave resistance BR1, and the input end of the first chopping current sensor BCT1 is connected between the output end of the first chopper BCH1 and the input end of the first diode BRD1. The second chopping current sensor BCT2 is used to measure the chopping current of the second current inversion module INVMK2. The output end of the second chopping current sensor BCT2 is connected to the input end of the second wave resistance BR2, and the input end of the second chopping current sensor BCT2 is connected between the output end of the second chopper BCH2 and the input end of the second diode BRD2. The chopping current sensor is used to measure the chopping current generated by the inversion module and provide real-time current data for the control and protection system. The wave resistance is used to filter out high-frequency interference in the current signal, ensure that the signal output by the sensor is more stable, and help improve the measurement accuracy and the reliability of the control system.

[0026] The motor module is provided with a first inversion current sensor CTU1 and a second inversion current sensor CTV1. One end of the first inversion current sensor CTU1 is connected between the output end of the first inverter IG1U and the input end of the second inverter IG2U, and the other end is connected to the U-phase line of the first motor set 4. One end of the second inversion current sensor CTV1 is connected between the output end of the third inverter IG1V and the input end of the fourth inverter IG2V, and the other end is connected to the V-phase line of the first motor set 4, and is used to measure the inversion current of the first motor set 4 with U and V phase inputs. The motor module is also provided with a third inversion current sensor CTU2 and a fourth inversion current sensor CTV2. One end of the third inversion current sensor CTU2 is connected between the output end of the seventh inverter IG1U and the input end of the eighth inverter IG2U, and the other end is connected to the U-phase line of the second motor set 5. One end of the fourth inversion current sensor CTV2 is connected between the output end of the ninth inverter IG1V and the input end of the tenth inverter IG2V, and the other end is connected to the V-phase line of the second motor set 5, and is used to measure the inversion current of the second motor set 5 with U and V phase inputs.

[0027] The fixed discharge resistor 3 is connected in parallel with the current inversion module 2; the fixed discharge resistor 3 includes a plurality of discharge resistors, the first discharge resistor R1 and the second discharge resistor R2 are connected in series, and the third discharge resistor R3 and the fourth discharge resistor R4 are connected in series. The fixed discharge resistor 3 is connected in parallel with the current inversion module 2. The capacitor in the current inversion module 2 is connected in parallel with the inversion module, and the fixed discharge resistor 3 is also connected in parallel with the two. In a high-voltage or sudden current environment, the parallel connection of the fixed discharge resistor 3 can limit the transient current during discharge and avoid damage to the capacitor caused by excessive current impact. In addition, when the capacitor discharges too quickly when powered off, high-frequency electromagnetic interference may be generated. The fixed discharge resistor 3 can slow down the discharge process and reduce the generation of electromagnetic interference. The capacitor will still store charges after power-off. If not released in time, it may pose a risk of electric shock or circuit damage. Connecting the fixed discharge resistor 3 in parallel can allow the capacitor to gradually discharge through the resistor after power-off, consuming the charges in the capacitor and avoiding danger.

[0028] The charge and discharge module 1 is provided with a maintenance switch DS. One end of the maintenance switch DS is connected to the output end of the first sensor DCPT1, and the other end is connected to the input end of the charge and discharge resistor CHRe, which is used to release the charges in the circuit during maintenance to ensure safety.

[0029] The circuit is also provided with a negative line current sensor DCCT2. The input end is connected to the output end of the first sensor DCPT1, and the output end of the negative line current sensor DCCT2 is grounded. It is used to monitor the current of the DC bus, providing necessary data for the real-time control, overcurrent protection, and current balance of the system. At the same time, grounding forms a complete measurement loop, and grounding can stabilize the measurement signal of the sensor, reduce external interference, and improve the measurement accuracy.

[0030] During the charge and discharge process, the main disconnector MS, the bus disconnector BS, and the high-speed circuit breaker HB are all closed. The grid current enters the circuit from the 501 line. After the current flows through the main disconnector MS, the main fuse MF, and the high-speed circuit breaker HB in sequence, the first electronic control switch CHB closes to charge the charge and discharge resistor CHRe; when the voltage of the charge and discharge resistor CHRe is the same as the grid voltage, the first electronic control switch CHB disconnects, and the second electronic control switch LB closes. At this time, the charge and discharge resistor CHRe discharges, and the current flows into the input end of the filter reactor FL from the output end of the charge and discharge resistor CHRe. The current is filtered for harmonics through the filter reactor FL, and a stable current is output from the output end of the filter reactor FL. After being buffered by the fixed discharge resistor 3, it charges the first capacitor FC1 and the second capacitor FC2, making the first capacitor FC1 and the second capacitor FC2 the same as the grid voltage. At this time, the current inversion module starts to work, and the DC current enters the inversion module and is converted into AC current through the IGBT inverter and flows into the three-phase motor.

[0031] During the maintenance process, the main disconnector MS and the high-speed circuit breaker HB are both disconnected, the maintenance switch DS is closed, and the circuit is grounded to form a complete loop, discharging the excess charge in the circuit.

[0032] With the above technical solution, for the traction system circuit of the dual-inverter module of the present utility model, by setting the structure of the dual-inverter module, the power output can be better distributed, the load pressure on a single inverter module can be reduced, the inversion efficiency and reliability can be improved, and the temperature of the traction system can be effectively reduced; in addition, a charge-discharge resistor and a fixed discharge resistor are provided. The charge-discharge resistor avoids excessive transient current causing circuit shock, controls the current change, and ensures the safety and stability of the circuit; the fixed discharge resistor ensures that the capacitor does not store residual charge, prevents electric shock and other potential dangers, and at the same time maintains the stability of the circuit. At the same time, a Hall sensor is also adopted to improve the detection accuracy of the circuit at low speeds.

[0033] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present utility model.

Claims

1. A traction system circuit of a dual-inverter module, characterized in that: It includes a charge and discharge module, a current inversion module, and a motor module; the charge and discharge module includes a charge and discharge resistor CHRe and a fixed discharge resistor. The output end of the charge and discharge resistor CHRe is connected to the input end of the fixed discharge resistor. The input end of the fixed discharge resistor is also connected to the input end of the current inversion module, and the output end of the fixed discharge resistor is connected to the output end of the current inversion module; the current inversion module includes a first current inversion module INVMK1 and a second current inversion module INVMK2, and the two inversion modules are connected in parallel; the motor module includes a first motor group and a second motor group. The first current inversion module INVMK1 is connected to the input end of the first motor group, and the second current inversion module INVMK2 is connected to the input end of the second motor group; a second sensor DCPT2 is provided at both ends of the current inversion module, and both ends of the second sensor DCPT2 are connected to both ends of the current inversion module. A first sensor DCPT1 for measuring the grid voltage is also provided in the main circuit. One end of the first sensor DCPT1 is connected to the charge and discharge module, and the other end is connected to the current inversion module.

2. The traction system circuit of the dual-inverter module according to claim 1, characterized in that: The charge and discharge module is also provided with a first electric control switch CHB and a second electric control switch LB. When the charge and discharge resistor CHRe is charging, the first electric control switch CHB is closed and the second electric control switch LB is opened; when the charge and discharge resistor CHRe is discharging, the first electric control switch CHB is opened and the second electric control switch LB is closed.

3. The traction system circuit of the dual-inverter module according to claim 1, characterized in that: The charge and discharge module is also provided with a filter reactor FL. The output end of the charge and discharge resistor is connected to the input end of the filter reactor FL, and the input end of the fixed discharge resistor is connected to the output end of the filter reactor FL.

4. The traction system circuit of the dual-inverter module according to claim 1, characterized in that: The circuit is also provided with a main disconnect switch MS, a main fuse MF, and a high-speed circuit breaker HB connected in series in sequence; the circuit is provided with a positive line current sensor DCCT1. One end of the positive line current sensor DCCT1 is connected to the high-speed circuit breaker HB, and the other end is connected to the charge and discharge module.

5. The traction system circuit of the dual-inverter module according to claim 1, characterized in that: Both the first current inversion module INVMK1 and the second current inversion module INVMK2 include a capacitor and an inversion unit connected in parallel; the inversion unit includes a chopper, a diode, and a plurality of inverters; among them, the plurality of inverters form U, V, and W three-phase inversion branches, and each phase inversion branch includes two inverters connected in series; the chopper and the diode are connected in series and then connected in parallel with the three-phase inversion branch.

6. The traction system circuit of the dual-inverter module according to claim 5, characterized in that: The current inversion module is also provided with a first chopping current sensor BCT1 and a second chopping current sensor BCT2. The first chopping current sensor BCT1 is used to measure the chopping current of the first current inversion module INVMK1. The output end of the first chopping current sensor BCT1 is connected to the input end of the first wave impedance resistor BR1, and the input end of the first chopping current sensor BCT1 is connected between the output end of the first chopper BCH1 and the input end of the first diode BRD1. The second chopping current sensor BCT2 is used to measure the chopping current of the second current inversion module INVMK2. The output end of the second chopping current sensor BCT2 is connected to the input end of the second wave impedance resistor BR2, and the input end of the second chopping current sensor BCT2 is connected between the output end of the second chopper BCH2 and the input end of the second diode BRD2.

7. The traction system circuit of the dual-inverter module according to claim 5, characterized in that: The motor module includes a plurality of inverter current sensors for monitoring the inverter currents of the first motor group and the second motor group. The first inverter current sensor CTU1 and the second inverter current sensor CTV1 are connected to the first current inversion module INVMK1 to monitor the inverter currents input to the U and V phases of the first motor group. The third inverter current sensor CTU2 and the fourth inverter current sensor CTV2 are connected to the second current inversion module INVMK2 to monitor the inverter currents input to the U and V phases of the second motor group.

8. The traction system circuit of the dual-inverter module according to any one of claims 1-7, characterized in that: The fixed discharge resistor is connected in parallel with the current inversion module. The fixed discharge resistor includes a plurality of discharge resistors. The first discharge resistor R1 and the second discharge resistor R2 are connected in series, and the third discharge resistor R3 and the fourth discharge resistor R4 are connected in series, and then these two series units are connected in parallel.

9. The traction system circuit of the dual-inverter module according to any one of claims 1-7, characterized in that: The charge and discharge module is provided with a maintenance switch DS. One end of the maintenance switch DS is connected to the output end of the first sensor DCPT1, and the other end is connected to the input end of the charge and discharge resistor CHRe.

10. The traction system circuit of the dual-inverter module according to any one of claims 1-7, characterized in that: The circuit is also provided with a negative line current sensor DCCT2. The input end is connected to the output end of the first sensor DCPT1, and the output end of the negative line current sensor DCCT2 is grounded.

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