High-power bidirectional DC conversion circuit
By designing a high-power bidirectional DC conversion circuit, using bidirectional DCDC chopping modules and current sensors, the braking energy recovery and utilization of the mine car system is realized, solving the problem of energy in the existing technology that cannot be recycled and utilized, and improving the energy utilization rate and power utilization of diesel engines.
Patent Information
- Application Number
- CN202420592385.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-25
- Publication Date
- 2025-03-28
- Estimated Expiration
- 2034-03-25
AI Technical Summary
In the existing high-power hybrid mine car system, energy cannot be recycled and the power of the diesel engine is limited, so it cannot be increased when the system needs to provide greater energy, and the power of the diesel engine is not fully utilized when the motor drives the output of the small load motor.
A high-power bidirectional DC conversion circuit is designed to realize the recovery and utilization of braking energy through components such as bidirectional DCDC chopping modules and current sensors, and to realize the power distribution between devices through high-speed CAN communication.
The braking energy recovery and utilization of the mine car drive system is realized, which reduces the energy consumption of the mine car during operation, improves the energy utilization rate, and improves the power utilization of the diesel engine when the system needs to provide greater energy.
Smart Images
Figure CN222691593U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of direct current conversion circuits, in particular to a high-power bidirectional direct current conversion circuit. Background Art
[0002] In a high-power hybrid mine car system, the diesel engine is usually used to generate electricity, which is rectified by a rectifier and then powered by a traction inverter. The diesel engine drives the synchronous generator to work, and the DC voltage after the voltage is rectified by the rectifier is fed to the traction inverter to reverse drive the traction motor, thereby driving the mine car to move. Sometimes the electric brake controls the traction motor to generate electricity through the traction inverter, and the DC voltage is divided by the DC chopper to power the brake resistor, consuming energy. The existing technology has the following problems: First, the energy is not recycled; second, when the system needs to provide more energy, there is no room for improvement due to the power limit of the diesel engine; third, the diesel engine power is not fully utilized when the motor is driven to output under a small load. In order to respond to the national call for energy conservation and emission reduction, it is necessary to develop a traction power supply powered by a high-power bidirectional DC converter for the recovery and utilization of braking energy in the mine car drive system, reduce the energy consumption of the mine car during operation, and increase the energy utilization rate of the mine car. Utility Model Content
[0003] The purpose of the utility model is to solve the problems raised in the above background technology and provide a high-power bidirectional DC conversion circuit.
[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a high-power bidirectional DC conversion circuit, wherein one end of the fuse FU1 is connected to the DC bus positive electrode HV+, and the other end is connected to the voltage sensor TV1 positive electrode and one end of the contactor KM1, and the voltage sensor TV1 negative electrode is connected to the DC bus negative electrode HV-; the other end of the contactor KM1 is connected to the input discharge resistor R5, one end of the input capacitor C1, the voltage sensor TV3 positive electrode and the drain of the chopper module VT1; the discharge resistor R5 and the other end of the input capacitor C1 are connected to the DC bus negative electrode HV-, and the voltage sensor TV3 negative electrode is connected to the DC bus negative electrode HV-; the source of the chopper module VT1 is connected to the drain of the chopper module VT2, one end of the capacitor C2 and the positive electrode of the voltage sensor TV4; the source of the chopper module VT2 is connected to the drain of the chopper module VT3 and one end of the inductor L11; the source of the chopper module VT3 is connected to the drain of the chopper module VT4 and the other end of the capacitor C2 and the voltage sensor The source of the chopper module VT4 is connected to the negative electrode HV- of the DC bus, and the other end of the inductor L11 is connected to one end of the capacitor C11, one end of the resistor R7, the positive electrode of the voltage sensor TV16, and one end of the contactor KM2 and the contactor KM3; the other end of the capacitor C11, the other end of the resistor R7, and the negative electrode of the voltage sensor TV16 are connected to the negative electrode HV- of the DC bus; the other end of the contactor KM2 is connected to the positive electrode DC+ of the power battery, the other end of the contactor KM3 is connected to one end of the pre-charging resistor R6, the other end of the pre-charging resistor R6 is connected to the positive electrode DC+ of the power battery, and the negative electrode DC- of the power battery is connected to the negative electrode HV- of the DC bus; the total cable from the contactor KM1 to the resistor R5, the capacitor C1, and the drain of the chopper module VT1 passes through the current sensor TA1, and the total cable from the inductor L11 to the resistor R7, the capacitor C11, the positive electrode of the voltage sensor TV16, the contactor KM2, and the contactor KM3 passes through the current sensor TA2.
[0005] Furthermore, each of the chopper modules VT1, VT2, VT3, and VT4 is connected in parallel with an RCD absorption module.
[0006] Furthermore, the chopper modules VT1, VT2, VT3, and VT4 use 2MBI400U4H-170 switching tubes.
[0007] Furthermore, the fuse FU1 adopts a fast fuse isolating switch.
[0008] Furthermore, the contactor KM1 adopts a CL111502P24ET-U2 contactor.
[0009] Furthermore, the capacitors are all 1000V / 1000uF.
[0010] Furthermore, the voltage sensors all adopt LT 208-S7 / SP8 voltage sensors.
[0011] Compared with the prior art, the beneficial effects of the utility model are: 1) current sensors TA1 and TA2 are provided to collect device current in real time, and current balancing of multiple devices can be achieved through a droop control algorithm, the uneven flow between devices can be controlled within 15%, and power distribution between devices can be achieved through high-speed CAN communication; 2) the braking energy recovery and utilization of the mine car drive system can be realized in the existing space, the energy consumption of the mine car during operation can be reduced, and the energy utilization rate of the mine car can be increased.
[0012] In order to more clearly illustrate the functional characteristics and structural parameters of the utility model, further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0014] Figure 1 The figure is a schematic diagram of a high-power bidirectional DC conversion circuit. DETAILED DESCRIPTION
[0015] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments; based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0016] A high-power bidirectional DC conversion circuit includes bidirectional DCDC chopper modules VT1, VT2, VT3, and VT4. Each module has RCD absorption, supporting capacitors C1, C2, and C11, voltage sensors TV1, TV3, TV4, and TV16, current sensors TA1 and TA2, high-voltage side contactor KM1, low-voltage side contactors KM2 and KM3, fuse FU1, pre-charge resistor R6, discharge resistors R7 and R5, and inductor L11. The bidirectional DCDC chopper module is used for braking energy recovery and utilization of a mine car drive system, and is connected to a high-voltage side contactor and a low-voltage side contactor; the high-voltage side of the converter is connected to the traction converter busbars HV+ and HV-, and the low-voltage side is connected to the positive and negative electrodes DC+ and DC- of a power battery. When the mine car brakes, the bus high voltage increases, and the bidirectional DCDC converter controls the energy of the bus to chop and charge the power battery; when the mine car is towing, the converter controls the discharge of the power battery to transfer the battery energy to the traction converter bus, and then the traction converter provides it to the motor, thereby realizing the recovery and reuse of braking energy.
[0017] like Figure 1 As shown, one end of the fuse FU1 is connected to the DC bus positive electrode HV+, and the other end is connected to the positive electrode of the voltage sensor TV1 and one end of the contactor KM1, and the negative electrode of the voltage sensor TV1 is connected to the DC bus negative electrode HV-; the other end of the contactor KM1 is connected to the input discharge resistor R5, one end of the input capacitor C1, the positive electrode of the voltage sensor TV3 and the drain of the chopper module VT1; the other end of the discharge resistor R5 and the input capacitor C1 is connected to the DC bus negative electrode HV-, and the negative electrode of the voltage sensor TV3 is connected to the DC bus negative electrode HV-; the source of the chopper module VT1 is connected to the drain of the chopper module VT2, one end of the capacitor C2 and the positive electrode of the voltage sensor TV4; the source of the chopper module VT2 is connected to the drain of the chopper module VT3 and one end of the inductor L11; the source of the chopper module VT3 is connected to the drain of the chopper module VT4, the other end of the capacitor C2 and the negative electrode of the voltage sensor TV4; the source of the chopper module VT4 Connect the negative pole HV- of the DC bus, the other end of the inductor L11 is connected to one end of the capacitor C11, one end of the resistor R7, the positive pole of the voltage sensor TV16, and one end of the contactor KM2 and the contactor KM3; the other end of the capacitor C11, the other end of the resistor R7, and the negative pole of the voltage sensor TV16 are connected to the negative pole HV- of the DC bus; the other end of the contactor KM2 is connected to the positive pole DC+ of the power battery, the other end of the contactor KM3 is connected to one end of the pre-charging resistor R6, the other end of the pre-charging resistor R6 is connected to the positive pole DC+ of the power battery, and the negative pole DC- of the power battery is connected to the negative pole HV- of the DC bus; the total cable from the contactor KM1 to the resistor R5, the capacitor C1, and the drain of the chopper module VT1 passes through the current sensor TA1, and the total cable from the inductor L11 to the resistor R7, the capacitor C11, the positive pole of the voltage sensor TV16, the contactor KM2, and the contactor KM3 passes through the current sensor TA2.
[0018] When the high-power bidirectional converter starts working, the capacitors C2, C1, and C11 are pre-charged first, the contactor KM3 is energized, the VT4 switch is turned on, and the battery energy passes through the resistor R6, the contactor KM3, the filter inductor L11, and the diodes integrated in the chopper modules VT1 and VT2 to charge C2, C1, and C11 at the same time. When the capacitor voltage of C2 is close to half of the battery voltage, the VT4 switch is turned off, and the battery energy continues to charge C1 and C11. When the capacitor voltage of C11 is close to the battery voltage, the contactor KM2 is energized; the switches of the chopper modules VT4 and VT3 are switched on and off alternately, working in the boost mode, charging C1. When the voltage of C1 is close to the DC bus voltage, KM1 is energized and the pre-charging ends.
[0019] In order to detect the capacitor voltage, voltage sensors TV1, TV4, TV3, and TV16 are connected at both ends of the capacitor respectively. The controller controls the on and off of the chopper module by detecting the voltage on the capacitor and the battery charge and discharge instructions, thereby controlling the direction of energy flow; the size of the charging and discharging voltage is adjusted by adjusting the on and off time of the chopper module.
[0020] In boost discharge mode, the controller controls the chopper tube VT4 to be turned on, and the battery current flows from the positive electrode of the battery through KM2, L11, VT2 integrated anti-parallel diode, C2, VT4 back to the negative electrode of the battery, charging capacitor C2 and inductor L11. VT4 is turned off, and the current flows back to the negative electrode of the battery through the positive electrode of the battery, KM2, L11, VT1, VT2 integrated anti-parallel diode, C1, the inductor L11 is discharged, and the capacitor C1 is charged; the controller controls the chopper tube VT3 to be turned on, and the battery current flows from the positive electrode of the battery through KM2, L11, VT3, C2, VT1 integrated anti-parallel diode, C1 back to the negative electrode of the battery, capacitor C2 is discharged, capacitor C1 is charged, and inductor L11 is charged. VT3 is turned off, and the current flows back to the negative electrode of the battery through the positive electrode of the battery, KM2, L11, VT1, VT2 integrated anti-parallel diode, C1, the inductor L11 is discharged, and the capacitor C1 is charged;
[0021] In the step-down charging mode, the controller controls the chopper tube VT1 to be turned on, and the current flows from the positive electrode of the traction converter bus C1 through the anti-parallel diode integrated in VT1, C2, VT3, L11, and the positive electrode of C1 back to the negative electrode of C1, and C2, C11, and the inductor L11 are charged. When VT1 is turned off, the current flows back to the inductor L11 through the anti-parallel diode integrated in L11, C11, VT3, and VT4, and the inductor L11 is discharged and the capacitor C11 is charged; the controller controls the chopper tube VT2 to be turned on, and the current flows from the capacitor C2 through the anti-parallel diode integrated in VT2, L11, VT3, C11, and VT4 back to the capacitor C2, and the capacitor C2 is discharged, and the capacitor C11 is charged and the inductor L11 is charged. When VT2 is turned off, the current flows back to the inductor L11 through the anti-parallel diode integrated in L11, C11, VT3, and VT4, and the inductor L11 is discharged and the capacitor C11 is charged;
[0022] Specifically, in one embodiment, current sharing among multiple devices can be achieved through a droop control algorithm, and the uneven current among devices can be controlled within 15%. Power distribution among devices is achieved through high-speed CAN communication.
[0023] Specifically, in one embodiment, in order to further reduce the volume, the DCDC adopts a three-level topology. The three-level chopper topology has a strong advantage over the ordinary chopper circuit. The three-level output equivalent frequency is twice that of the ordinary two-level chopper at the same switching frequency. In addition, low-voltage IGBTs are more suitable for high switching frequencies than high-voltage IGBTs. At the same time, due to the advantages of duty cycle modulation of the three-level topology, under the same input and output conditions, the three-level output ripple current is only 1 / 4 of the ordinary ripple current, and will not increase with the reduction of the duty cycle, which has a great advantage for stable output.
[0024] Specifically, in one embodiment, when the device is running, KM3 is first closed to pre-charge the device, and after the pre-charging is completed, the KM2 contactor is closed. At this time, the bus voltage and the flying capacitor voltage are consistent with the input voltage. Then when the device is started, the bidirectional DCDC power supply is adjusted according to the traction side bus voltage, and after the high-voltage side voltage is adjusted to be consistent with the traction side bus voltage, the KM1 contactor is closed. The device can then perform normal charging and discharging functions. A fuse is provided on the high-voltage side to ensure rapid disconnection when the device fails, reducing secondary damage to the device. At the same time, a varistor is provided on the low-voltage side to prevent the high-voltage side voltage from entering the battery due to equipment failure, which provides a certain overvoltage protection function for the battery.
[0025] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.
[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A high-power bidirectional DC conversion circuit, characterized in that: One end of the fuse FU1 is connected to the DC bus positive electrode HV+, and the other end is connected to the positive electrode of the voltage sensor TV1 and one end of the contactor KM1, and the negative electrode of the voltage sensor TV1 is connected to the DC bus negative electrode HV-; the other end of the contactor KM1 is connected to the input discharge resistor R5, one end of the input capacitor C1, the positive electrode of the voltage sensor TV3 and the drain of the chopper module VT1; the other end of the discharge resistor R5 and the input capacitor C1 is connected to the DC bus negative electrode HV-, and the negative electrode of the voltage sensor TV3 is connected to the DC bus negative electrode HV-; the source of the chopper module VT1 is connected to the drain of the chopper module VT2, one end of the capacitor C2 and the positive electrode of the voltage sensor TV4; the source of the chopper module VT2 is connected to the drain of the chopper module VT3 and one end of the inductor L11; the source of the chopper module VT3 is connected to the drain of the chopper module VT4, the other end of the capacitor C2 and the negative electrode of the voltage sensor TV4; the source of the chopper module VT4 is connected to the Connect to the negative pole HV- of the DC bus, the other end of the inductor L11 is connected to one end of the capacitor C11, one end of the resistor R7, the positive pole of the voltage sensor TV16, and one end of the contactor KM2 and the contactor KM3; the other end of the capacitor C11, the other end of the resistor R7, and the negative pole of the voltage sensor TV16 are connected to the negative pole HV- of the DC bus; the other end of the contactor KM2 is connected to the positive pole DC+ of the power battery, the other end of the contactor KM3 is connected to one end of the pre-charging resistor R6, the other end of the pre-charging resistor R6 is connected to the positive pole DC+ of the power battery, and the negative pole DC- of the power battery is connected to the negative pole HV- of the DC bus; the total cable from the contactor KM1 to the resistor R5, the capacitor C1, and the drain of the chopper module VT1 passes through the current sensor TA1, and the total cable from the inductor L11 to the resistor R7, the capacitor C11, the positive pole of the voltage sensor TV16, the contactor KM2, and the contactor KM3 passes through the current sensor TA2.
2. A high-power bidirectional DC conversion circuit according to claim 1, characterized in that: Each of the chopper modules VT1, VT2, VT3, and VT4 is connected in parallel with an RCD absorption module.
3. A high-power bidirectional DC conversion circuit according to claim 1, characterized in that: The chopper modules VT1, VT2, VT3, and VT4 use 2MBI400U4H-170 switching tubes.
4. A high-power bidirectional DC conversion circuit according to claim 1, characterized in that: Fuse FU1 adopts fast fuse isolating switch.
5. A high-power bidirectional DC conversion circuit according to claim 1, characterized in that: Contactor KM1 uses CL111502P24ET-U2 contactor.
6. A high-power bidirectional DC conversion circuit according to claim 1, characterized in that: The capacitors are all 1000V / 1000uF.
7. A high-power bidirectional DC conversion circuit according to claim 1, characterized in that: The voltage sensors all use LT 208-S7 / SP8 voltage sensors.