A power-off damping device for a servo drive system

Abstract

The application discloses a power-off buffer device for a servo transmission system, belonging to the field of power electronics, which comprises an energy storage capacitor C2 for outputting electric energy during power-off; a main circuit topology connected with a power grid and the energy storage capacitor C2, which is used for charging the energy storage capacitor C2 in a normal state or temporarily supplying power to a single-phase load of the servo transmission system by the energy storage capacitor during power-off; and a control unit, which outputs a parking signal to the servo transmission system when receiving an external power-off signal, wherein the main circuit topology is a double active bridge topology structure or a non-isolated H-bridge topology structure, and the upper and lower bridge arms at one end of the main circuit topology are connected with the power grid, and the upper and lower bridge arms at the other end of the main circuit topology are connected with the energy storage capacitor. The control unit is used for acquiring the external power-off signal, and when the power-off signal is acquired, the parking signal is output to the servo transmission system, and a short-time energy supply is realized by using the energy storage capacitor, so that the equipment is parked together with the servo transmission system.

Description

Technical Field

[0001] This utility model relates to the field of power electronics, specifically to a power failure buffer device for a servo drive system. Background Technology

[0002] With the application of servo multi-axis linkage electronic cam function in the machinery and equipment industry, the traditional mechanical cam linkage structure is gradually being replaced. However, some industries have encountered a difficult problem in the process of promoting this: an unexpected power failure during equipment operation will cause multiple transmission shafts that are normally strictly linked to lose speed, resulting in collisions of related mechanical structures or molds, and bringing huge after-sales service costs.

[0003] To address this issue, equipment manufacturers have designed and configured three-phase high-power UPS systems for customers experiencing power outages. However, this solution still has significant problems: Firstly, UPS systems are expensive; Secondly, the system's battery and power supply are too large to be compatible with the equipment; Thirdly, when an unexpected power outage occurs, manual operation to shut down the equipment is still required. If the power grid outage is not detected and the UPS system is allowed to run out of power, a power outage may still occur. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a power failure buffer device for servo drive systems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A power failure buffer device for a servo drive system, comprising: Energy storage capacitor C2 is used for power output when power is off; The main circuit topology connects the power grid and the energy storage capacitor C2, and is used to charge the energy storage capacitor C2 under normal conditions or to temporarily power the single-phase load of the servo drive system by the energy storage capacitor when the power is off. When the control unit receives an external power failure signal, it outputs a stop signal to the servo drive system. The main circuit topology is a dual active bridge topology or a non-isolated H-bridge topology, and the upper and lower bridge arms at one end of the main circuit topology are connected to the power grid, while the upper and lower bridge arms at the other end are connected to an energy storage capacitor.

[0006] The energy storage capacitor C2 is also connected to the three-phase load of the servo drive system through a non-isolated secondary circuit topology, and provides temporary power to the three-phase load in the event of a power outage.

[0007] The secondary circuit topology is an H-bridge topology or a topology consisting of two MOSFETs and two Schottky diodes.

[0008] The three-phase load terminal is also equipped with a wiring fault detection circuit and an isolation circuit.

[0009] The isolation circuit includes two Schottky diodes connected in reverse parallel at the phase lines of the three-phase load.

[0010] The wiring fault detection circuit includes a detection terminal for collecting the highest and lowest voltages of each busbar of the three-phase load, and a relay K1 controlled by the control unit based on the signals from the detection terminal.

[0011] The dual active bridge topology includes eight MOSFETs, a transformer T1, and an inductor L1. Pins 2 of MOSFET Q1 and Q2 are connected to the positive input terminal of the power supply. Pins 3 of MOSFET Q6 and Q7 are connected to the negative input terminal of the power supply. Pins 3 of MOSFET Q1 and Q6 are connected to one end of the front winding of the transformer. Pins 3 of MOSFET Q2 and Q7 are connected to the other end of the front winding of the transformer T1. Pins 2 of MOSFET Q3 and Q4 are connected to the positive terminal of the energy storage capacitor. Pins 3 of MOSFET Q8 and Q9 are connected to the negative terminal of the energy storage capacitor. Pins 3 of MOSFET Q3 and Q8 are connected to one end of the rear winding of the transformer T1 through inductor L1. Pins 3 of MOSFET Q4 and Q9 are connected to the other end of the rear winding of the transformer T1.

[0012] The non-isolated H-bridge topology includes four MOSFETs and an inductor L1. Pin 2 of MOSFET Q1 is connected to the positive input terminal of the power supply, pin 3 of MOSFET Q3 is connected to the negative input terminal of the power supply, pin 3 of MOSFET Q1 and pin 2 of MOSFET Q3 are connected to one end of inductor L1, pin 2 of MOSFET Q2 is connected to the positive terminal of the energy storage capacitor, pin 3 of MOSFET Q4 is connected to the negative terminal of the energy storage capacitor, and pin 3 of MOSFET Q2 and pin 2 of MOSFET Q4 are connected to the other end of inductor L1.

[0013] A rectifier and filter circuit is also provided between the power grid and the main circuit topology.

[0014] The beneficial effects of this utility model are: the control unit acquires the external power failure signal, and when the power failure signal is acquired, it outputs a stop signal to the servo drive system, while the energy storage capacitor provides a short-term energy supply to cooperate with the servo drive system to complete the equipment shutdown. Attached Figure Description

[0015] Figure 1 This is a logic block diagram of the present invention.

[0016] Figure 2 This is the circuit schematic diagram of this utility model.

[0017] Figure 3 This is a circuit diagram of the non-isolated H-bridge topology of this utility model.

[0018] Figure 4 This is a circuit diagram of another topology of the secondary circuit topology of this utility model.

[0019] Figure 5 , Figure 6 and Figure 7 Combining to form Figure 2 . Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0022] The main function of this application is to replace the UPS, and at the same time, it can output a stop signal to the servo drive system when the power is off, so that the corresponding servo drive system can complete the stop action under the temporary power supply of the energy storage capacitor, ensuring the safe and stable shutdown of the equipment, while reducing costs.

[0023] This utility model discloses a power failure buffer device for a servo drive system, which includes an energy storage capacitor C2 used as an auxiliary power supply, a control unit for outputting a stop signal, and a main circuit topology 200 connecting the energy storage capacitor C2 and the mains input terminal.

[0024] The energy storage capacitor C2 can be a supercapacitor or can be composed of multiple large-capacity capacitors connected in series. Normally, it can be charged by the power grid through the main circuit topology 200. When the power is off, it can directly supply power to the servo drive system and control unit in reverse.

[0025] The main circuit topology 200 connects the power grid and the energy storage capacitor C2, and is used to charge the energy storage capacitor C2 under normal conditions or to temporarily power the single-phase load of the servo drive system by the energy storage capacitor when the power is off. The main circuit topology 200 is a dual active bridge topology or a non-isolated H-bridge topology, and the upper and lower bridge arms at one end of the main circuit topology are connected to the power grid, while the upper and lower bridge arms at the other end are connected to an energy storage capacitor.

[0026] The energy stored in an energy storage capacitor is related to the capacitor voltage. To improve the utilization rate of the energy storage capacitor, a wide-range voltage regulation topology must be used to control the transmission of capacitor energy.

[0027] Energy storage capacitors need to distribute the stored energy evenly to the single-phase load side and the three-phase load side according to the load demand. Since there are common-mode and differential-mode voltage fluctuations on both sides, electrical isolation must be used to achieve energy transfer.

[0028] Based on the above design requirements, the single-phase load side and the energy storage side adopt a dual active bridge topology (DAB) to achieve isolated bidirectional power transmission. The topology includes, but is not limited to, variants based on the DAB structure.

[0029] like Figure 2 and Figure 5 As shown, the dual active bridge topology includes eight MOSFETs, a transformer T1, and an inductor L1. Pins 2 of MOSFET Q1 and Q2 are connected to the positive input terminal of the power supply. Pins 3 of MOSFET Q6 and Q7 are connected to the negative input terminal of the power supply. Pins 3 of MOSFET Q1 and Q6 are connected to one end of the front winding of the transformer. Pins 3 of MOSFET Q2 and Q7 are connected to the other end of the front winding of the transformer T1. Pins 2 of MOSFET Q3 and Q4 are connected to the positive terminal of the energy storage capacitor. Pins 3 of MOSFET Q8 and Q9 are connected to the negative terminal of the energy storage capacitor. Pins 3 of MOSFET Q3 and Q8 are connected to one end of the rear winding of the transformer T1 through inductor L1. Pins 3 of MOSFET Q4 and Q9 are connected to the other end of the rear winding of the transformer T1.

[0030] When only a single-phase load needs to be powered, a non-isolated H-bridge topology can be used.

[0031] like Figure 3 As shown, the non-isolated H-bridge topology includes four MOSFETs and an inductor L1. Pin 2 of MOSFET Q1 is connected to the positive input terminal of the power supply, pin 3 of MOSFET Q3 is connected to the negative input terminal of the power supply, pin 3 of MOSFET Q1 and pin 2 of MOSFET Q3 are connected to one end of inductor L1, pin 2 of MOSFET Q2 is connected to the positive terminal of the energy storage capacitor, pin 3 of MOSFET Q4 is connected to the negative terminal of the energy storage capacitor, and pin 3 of MOSFET Q2 and pin 2 of MOSFET Q4 are connected to the other end of inductor L1.

[0032] When the control unit receives an external power failure signal, it outputs a stop signal to the servo drive system. This application mainly samples the power grid input signal and, upon determining that a power failure has occurred, outputs a corresponding stop signal to the control system of the connected device used to control the servo drive system. This allows the control system to issue stop signals to each servo drive system of the device while powered by the energy storage capacitor C2. At the same time, each servo drive system of the device is also temporarily powered by the energy storage capacitor C2. Therefore, the capacity of the energy storage capacitor C2 needs to meet the power requirements of each servo drive system to complete the stop.

[0033] This application uses a single-phase AC input, rectified output to power the control unit and single-phase servo system, as well as the internal control power supply.

[0034] Because the power supplies for PLCs, switching power supplies, and single-phase servo systems are currently rectified internally and are compatible with DC power supply, this application has chosen DC power supply for the control system and single-phase servo power supply, while avoiding power supply for single-phase loads unrelated to mechanical structure (such as heating or single-phase constant speed motors).

[0035] The power supply for the three-phase servo is still mainly based on the three-phase AC input. In the event of a power grid outage, this application provides power to the three-phase servo through the DC bus port of the three-phase servo.

[0036] The energy storage capacitor C2 is also connected to the three-phase load of the servo drive system through a non-isolated secondary circuit topology 300, and provides temporary power to the three-phase load in the event of a power outage.

[0037] The secondary circuit topology 300 is an H-bridge topology or a topology consisting of two MOSFETs and two Schottky diodes.

[0038] The DC power on the three-phase side is relatively large, so a non-isolated topology is adopted to achieve wide-voltage power transmission, including but not limited to the following two topology forms: like Figure 2 and Figure 6 As shown, it consists of two MOSFETs, two Schottky diodes, and an inductor L2. Pin 2 of MOSFET Q5 is connected to the positive terminal of energy storage capacitor C2, and the anode of Schottky diode D2 is connected to the negative terminal of energy storage capacitor C2. Meanwhile, pin 3 of MOSFET Q5 and the cathode of Schottky diode D2 are connected to one end of inductor L2. On the other side, pin 3 of MOSFET Q10 serves as the negative output terminal, and the cathode of Schottky diode D1 serves as the positive output terminal. Pin 2 of MOSFET Q10 and the anode of Schottky diode D1 are connected to the other end of inductor L2, forming an H-bridge structure.

[0039] Another topology is as follows Figure 4As shown, the circuit includes four MOSFETs and an inductor L2. Pin 2 of MOSFET Q5 is connected to the positive terminal of the energy storage capacitor C2, pin 3 of MOSFET Q6 is connected to the negative terminal of the energy storage capacitor, pin 3 of MOSFET Q5 and pin 2 of MOSFET Q6 are connected to one end of inductor L2, pin 2 of MOSFET Q7 is connected as the positive output terminal, pin 3 of MOSFET Q8 is connected as the negative output terminal, and pin 3 of MOSFET Q7 and pin 2 of MOSFET Q8 are connected to the other end of inductor L2.

[0040] An electrolytic capacitor C3 is connected in parallel between the positive and negative output terminals of the two topologies to filter the output.

[0041] There is a rectifier bridge between single-phase servo power supply lines, so there is no safety risk of direct connection. However, the DC bus of a three-phase servo is directly connected to the internal power electronic devices of the servo. If three-phase servo buses of different sizes in a system are directly connected together, there is a huge safety hazard. If the polarity of the DC bus is accidentally reversed, it will directly cause damage to the servo.

[0042] To avoid this serious consequence, the present invention provides a multi-servo DC bus wiring fault detection circuit 400 and an isolation circuit 500.

[0043] Power diodes are used to provide unidirectional power supply support for multiple three-phase servo buses and ensure safe isolation between servos. Signal diodes are used to detect the highest voltage of multiple three-phase servo buses. By collecting the highest and lowest voltages of multiple three-phase servo buses, external wiring faults and servo operating status are determined, and the on / off state of the output relays is controlled to ensure the safety of external wiring.

[0044] That is, the isolation circuit includes two Schottky diodes connected in reverse parallel at the phase lines of the three-phase load.

[0045] The wiring fault detection circuit includes a detection terminal for collecting the highest and lowest voltages of each busbar of the three-phase load, and a relay K1 controlled by the control unit based on the signal from the detection terminal.

[0046] Specific circuit as follows Figure 2 and Figure 7 As shown, the positive output terminal of the secondary circuit topology 300 is connected to one side of the relay's switching terminal. At the same time, the coil of relay K1 and the control unit form a circuit, and the control unit controls the on and off of relay K1. The negative output terminal of the secondary circuit topology 300 is connected to one bus N_T1 or N_T2 of the three-phase load. At the same time, a diode D4 or D6 is connected in series with the bus N_T1 or N_T2. The other bus P_T1 or P_T2 of the three-phase load is connected to the other side of the relay K1's switching terminal through a diode D8 or D10. The diodes D4 or D6 and D8 or D10 are arranged with opposite orientations.

[0047] Simultaneously, a bypass wire is drawn from each of bus N_T1 or N_T2 and bus P_T1 or P_T2, and diodes D7 or D9 and D3 or D5 are connected in series respectively as detection signal outputs. The two wires are connected to diodes D8 or D4 through resistors R1 and R2 respectively. The two ends of resistors R1 and R2 are used as the highest voltage detection terminal and the lowest voltage detection terminal for different loads, respectively, and are connected to the control unit. By detecting the highest and lowest voltages, external wiring faults and servo operation status are determined, and the on / off state of the output relay is controlled to ensure the safety of external wiring.

[0048] Diodes D7 and D3 are oriented in opposite directions, as are diodes D5 and D9. The cathodes of diodes D3 and D5 are connected to resistor R1, and the cathodes of diodes D4 and D6 are connected to relay K1.

[0049] Furthermore, a rectifier and filter circuit 100 is provided between the power grid and the main circuit topology. The rectifier and filter circuit 100 includes a rectifier circuit and an electrolytic capacitor C1 connected in parallel between the two output terminals of the rectifier circuit.

[0050] like Figure 1 As shown, the specific logic of this utility model is as follows: After single-phase power is supplied, this embodiment draws power from the grid side to charge the energy storage capacitor C2, and detects the voltage status of the three-phase servo DC bus to control the output relay to engage. After detecting a power outage, the control unit outputs a signal to the PLC or control system to stop the servo drive system. During this process, this embodiment draws power from the energy storage capacitor to supply power to the loads on both sides, thus completing the stopping task.

[0051] When using this embodiment of the equipment, the power is directly cut off at the highest speed, and a safe stop is completed in about 1 second, so that the mechanical structure stops in a specific safe position and the remaining power is used to maintain power supply for 20 seconds. At the same time, the size is moderate and can be directly installed in the equipment distribution box or on the equipment rack.

[0052] Compared to UPS solutions, this application significantly reduces system cost and size.

[0053] The embodiments should not be regarded as limitations on the present invention, but any improvements made based on the spirit of the present invention should be within the protection scope of the present invention.

Claims

1. A power failure buffer device for a servo drive system, characterized in that: It includes: Energy storage capacitor C2 is used for power output when power is off; The main circuit topology (200) connects the power grid and the energy storage capacitor C2, and is used to charge the energy storage capacitor C2 under normal conditions or to temporarily power the single-phase load of the servo drive system by the energy storage capacitor when the power is off. When the control unit receives an external power failure signal, it outputs a stop signal to the servo drive system. The main circuit topology (200) is a dual active bridge topology or a non-isolated H-bridge topology, and the upper and lower bridge arms at one end of the main circuit topology are connected to the power grid, while the upper and lower bridge arms at the other end are connected to energy storage capacitors. The energy storage capacitor C2 is also connected to the three-phase load of the servo drive system through a non-isolated secondary circuit topology (300), and provides temporary power to the three-phase load in the event of a power outage. The secondary circuit topology (300) is an H-bridge topology or a topology consisting of two MOSFETs and two Schottky diodes. The three-phase load is also equipped with a wiring fault detection circuit (400) and an isolation circuit (500). The isolation circuit (500) includes two Schottky diodes connected in reverse parallel at the phase lines of the three-phase load. The wiring fault detection circuit (400) includes a detection terminal for collecting the highest and lowest voltages of each busbar of the three-phase load and a relay K1 controlled by the control unit according to the signal from the detection terminal.

2. The power failure buffer device for a servo drive system according to claim 1, characterized in that: The dual active bridge topology includes eight MOSFETs, a transformer T1, and an inductor L1. Pins 2 of MOSFET Q1 and Q2 are connected to the positive input terminal of the power supply. Pins 3 of MOSFET Q6 and Q7 are connected to the negative input terminal of the power supply. Pins 3 of MOSFET Q1 and Q6 are connected to one end of the front winding of the transformer. Pins 3 of MOSFET Q2 and Q7 are connected to the other end of the front winding of the transformer T1. Pins 2 of MOSFET Q3 and Q4 are connected to the positive terminal of the energy storage capacitor. Pins 3 of MOSFET Q8 and Q9 are connected to the negative terminal of the energy storage capacitor. Pins 3 of MOSFET Q3 and Q8 are connected to one end of the rear winding of the transformer T1 through inductor L1. Pins 3 of MOSFET Q4 and Q9 are connected to the other end of the rear winding of the transformer T1.

3. The power failure buffer device for a servo drive system according to claim 1, characterized in that: The non-isolated H-bridge topology includes four MOSFETs and an inductor L1. Pin 2 of MOSFET Q1 is connected to the positive input terminal of the power supply, pin 3 of MOSFET Q3 is connected to the negative input terminal of the power supply, pin 3 of MOSFET Q1 and pin 2 of MOSFET Q3 are connected to one end of inductor L1, pin 2 of MOSFET Q2 is connected to the positive terminal of the energy storage capacitor, pin 3 of MOSFET Q4 is connected to the negative terminal of the energy storage capacitor, and pin 3 of MOSFET Q2 and pin 2 of MOSFET Q4 are connected to the other end of inductor L1.

4. A power failure buffer device for a servo drive system according to claim 1, 2, or 3, characterized in that: A rectifier and filter circuit (100) is also provided between the power grid and the main circuit topology (200).

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