阅读说明：本技术 一种伺服压力机的保护装置及方法 (Protection device and method for servo press ) 是由 李岸然 李琦 李海明 邵光存 郭廷善 盛春营 范宏伟 裴德明 于 2021-01-20 设计创作，主要内容包括：本发明属于压力机技术领域,具体涉及到一种伺服压力机的保护装置及方法。本发明通过整流桥、软启动电路A、软启动电路B、储能电路、三相全桥逆变电路、核心控制器等组成的保护电路与电机相连,实现了伺服压力机无需配备制动器,突然断电依然可保证电机可控安全运行,给伺服压力机的电机提供短时工作电源,大大节约了成本。(The invention belongs to the technical field of presses, and particularly relates to a protection device and a protection method for a servo press. According to the invention, the protection circuit composed of the rectifier bridge, the soft start circuit A, the soft start circuit B, the energy storage circuit, the three-phase full-bridge inverter circuit, the core controller and the like is connected with the motor, so that the servo press machine does not need to be provided with a brake, the motor can be controlled and safely operated even if the power is cut off suddenly, a short-time working power supply is provided for the motor of the servo press machine, and the cost is greatly saved.)

1. A protection device of servo press is characterized in that: including rectifier bridge, soft start circuit A (1), soft start circuit B (2), energy storage circuit (4), three-phase full-bridge inverter circuit (3), core controller, motor, wherein: the soft start circuit A (1) comprises a soft start resistor R1 and a soft start resistor R2 which are connected in parallel; the soft start circuit B (2) comprises a soft start resistor R11 and a soft start resistor R12 which are connected in parallel; the energy storage circuit (4) comprises a plurality of energy storage branches connected in parallel, each energy storage branch is connected with a plurality of capacitors in series, and each capacitor is connected with a resistor in parallel; the rectifier bridge is connected with a 3-phase 380V power line, the anode of a diode D1 is connected with a single-phase 220V power line, the cathode of a diode D1 is connected with the cathode of the rectifier bridge, the cathode of the rectifier bridge is connected with one end of a soft start circuit A (1), the other end of the soft start circuit A (1) is connected with the anode of a thyristor S7, one end of a soft start circuit B (2) is connected with the anode of a capacitor in a three-phase full-bridge inverter circuit (3), the cathode of the thyristor S7 is connected with the anode of a capacitor in the three-phase full-bridge inverter circuit (3), the cathode of the capacitor in the three-phase full-bridge inverter circuit (3) is connected with the anode of the rectifier bridge, the anode of an energy storage circuit (4) is connected with the anode of a thyristor S7, the cathode of the energy storage circuit (4) is connected with the anode of the rectifier bridge, the cathode of the thyristor S7 is connected with the input of a DC-DC power module, the, a voltage signal acquired by a voltage sensor is input into a core controller, a current signal of a current sensor is input into the core controller, IGBT emitting electrodes in a three-phase full-bridge inverter circuit (3) are respectively connected with three-phase input terminals of a motor through cables, IGBT gate-level signals g in the three-phase full-bridge inverter circuit (3) are connected with g output signals of the core controller, an output shaft of the motor is connected with a crank connecting rod transmission mechanism of a press machine, and a control command of the press machine is input into the core controller; and a cable of the three-phase 380V power line is provided with a voltage sensor, and an input cable of the motor is provided with a current sensor.

2. A protection device for a servo press according to claim 1, characterized in that: the three-phase full-bridge inverter circuit (3) comprises a series capacitor formed by a capacitor C1 and a capacitor C2 and a topological structure formed by 6 IGBTs, wherein the 6 IGBTs are S1, S2, S3, S4, S5 and S6 respectively; the collector of S4 is connected with the emitter of S1, the collector of S5 is connected with the emitter of S2, the collector of S6 is connected with the emitter of S3, the emitters of S1, S2 and S3 are respectively connected with the three-phase input terminal of the motor through cables, IGBT gate level signals g of S1, S2, S3, S4, S5 and S6 are connected with g output signals of a core controller, the collectors of S1, S2 and S3 are respectively connected with the cathode of a rectifier bridge, and the emitters of S4, S5 and S6 are respectively connected with the anode of the rectifier bridge.

3. A protection device for a servo press according to claim 1, characterized in that: the energy storage circuit (4) comprises four energy storage branches connected in parallel, and the four energy storage branches are respectively as follows: the capacitor C3 is connected with the capacitor C4 in series, the capacitor C3 is connected with the resistor R3 in parallel, and the capacitor C4 is connected with the resistor R4 in parallel to form a first energy storage branch; a capacitor C5 is connected with a capacitor C6 in series, a capacitor C5 is connected with a resistor R5 in parallel, and a capacitor C6 is connected with a resistor R6 in parallel to form a second energy storage branch; a capacitor C7 is connected with a capacitor C8 in series, a capacitor C7 is connected with a resistor R7 in parallel, and a capacitor C8 is connected with a resistor R8 in parallel to form a third energy storage branch; the capacitor C9 is connected in series with the capacitor C10, the capacitor C9 is connected in parallel with the resistor R9, and the capacitor C10 is connected in parallel with the resistor R10 to form a fourth energy storage branch.

4. A protection device for a servo press according to claim 1, characterized in that: the voltage sensor is a straight-through voltage sensor, and the current sensor is a straight-through current sensor.

5. A protection device for a servo press according to claim 1, characterized in that: the capacitance selection in the energy storage circuit (4) is calculated according to the formula (1) to obtain:

wherein m is the mass of the slider; v is the average speed of the slide from bottom dead center to top dead center; c is the total capacitance of the energy storage circuit (4); and delta U is the difference value of the DC bus voltage.

6. The protection apparatus of a servo press according to claim 1, a protection method of a servo press, comprising the steps of:

the method comprises the following steps: the voltage of a three-phase 380V power line is connected to the three-phase input side of the rectifier bridge, a diode D1 is conducted, when the amplitude of a single-phase 220V voltage is in a positive half cycle, a capacitor in a three-phase full-bridge inverter circuit (3) is charged through a soft start circuit B (2), and when the voltage between the positive side and the negative side of a direct-current bus reaches 540V, the capacitor is not charged continuously;

step two: the DC-DC power supply module converts 540V into 24V, supplies power to the core controller, and the core controller sends an instruction to the rectifier bridge;

step three: the rectifier bridge receives an instruction of a core controller to start working, and rectifies the three-phase 380V alternating voltage into 540V direct voltage; the 540V dc voltage forms two branches: one branch is used for charging the energy storage circuit (4) through the soft start circuit A (1) until the full voltage is up to 540V, so that the thyristor S7 is not switched on; the other branch circuit provides direct-current voltage for the three-phase full-bridge inverter circuit (3);

step four: the core controller receives a press machine control instruction, starts to execute the press machine control instruction, and simultaneously outputs a PWM wave g signal to an IGBT gate-level signal g of the three-phase full-bridge inverter circuit (3) by combining the feedback of a current sensor signal;

step five: after the IGBT of the three-phase full-bridge inverter circuit (3) receives the gate-level signal g, the IGBT starts to execute switching action, the power supply is from the output voltage of the rectifier bridge, and the motor starts to rotate; in the working process of the motor, if the three-phase 380V power line is suddenly powered off, executing the step six;

step six: the three-phase 380V power line input by the rectifier bridge is suddenly cut off, the voltage sensor feeds back a voltage signal to the core controller in real time, the core controller immediately stores the current power grid voltage value into an EEPROM (electrically erasable programmable read-only memory) in the core controller, and the power grid voltage at the moment disappears to be regarded as a fault and is stored into a fault storage area FLASH in the core controller; the core controller enables the thyristor S7 to be conducted, the energy storage circuit (4) provides input power for the DC-DC power supply module and continuously supplies power for the core controller, the motor controls the sliding block to stop emergently, and the sliding block is enabled to return to the top dead center position from any current position by controlling the motor;

step seven: when the motor returns to the top dead center, the thyristor S7 is closed, no energy is supplied to the motor any more, and the whole safety protection process is completed.

Technical Field

The invention belongs to the technical field of servo presses, and particularly relates to a protection device and a protection method for a servo press.

Background

When the servo press is powered off in a factory, the servo motor can rotate freely under the condition that a brake is not arranged, so that the servo motor can seriously impact a die, the service life of the die is shortened, the forming damage to a workpiece is caused, and the economic loss is directly caused to a forming equipment manufacturer. Therefore, the problem that the servo motor is not out of control when the servo press is powered off needs to be solved.

CN107196404A entitled "UPS apparatus and power switching control method thereof" proposes a device for power failure, wherein the UPS apparatus is currently a conventional industrial backup device, but the UPS apparatus requires a backup power supply or a power battery, and the UPS apparatus itself uses an inverter as an input of a three-phase power supply, which is expensive.

Disclosure of Invention

The invention provides a protection device and a protection method for a servo press machine, aiming at solving the defects of the prior art.

The invention is realized by the following technical scheme:

the utility model provides a protection device of servo press, includes rectifier bridge, soft start circuit A, soft start circuit B, energy storage circuit, three-phase full-bridge inverter circuit, core controller, motor, wherein: the soft start circuit A comprises a soft start resistor R1 and a soft start resistor R2 which are connected in parallel; the soft start circuit B comprises a soft start resistor R11 and a soft start resistor R12 which are connected in parallel; the energy storage circuit comprises a plurality of energy storage branches connected in parallel, each energy storage branch is connected with a plurality of capacitors in series, and each capacitor is connected with a resistor in parallel; the rectifier bridge is connected with a 3-phase 380V power line, the anode of a diode D1 is connected with a single-phase 220V power line, the cathode of a diode D1 is connected with the cathode of the rectifier bridge, the cathode of the rectifier bridge is connected with one end of a soft start circuit A, the other end of the soft start circuit A is connected with the anode of a thyristor S7, one end of a soft start circuit B is connected with the anode of a capacitor in a three-phase full-bridge inverter circuit, the cathode of the thyristor S7 is connected with the anode of a capacitor in the three-phase full-bridge inverter circuit, the cathode of the capacitor in the three-phase full-bridge inverter circuit is connected with the anode of the rectifier bridge, the anode of an energy storage circuit is connected with the anode of a thyristor S7, the cathode of the energy storage circuit is connected with the anode of the rectifier bridge, the cathode of the thyristor S7 is connected with the input of a DC-DC power module, the output of the DC, the current signal acquired by the current sensor is input to the core controller, an upper bridge arm IGBT emitter in the three-phase full-bridge inverter circuit is respectively connected with a three-phase input terminal of the motor through a cable, an IGBT gate signal g in the three-phase full-bridge inverter circuit is connected with a g output signal of the core controller, an output shaft of the motor is connected with a crank connecting rod transmission mechanism of the press machine, and a control command of the press machine is input to the core controller; cables of the three-phase 380V power line respectively penetrate through the 3 paths of voltage sensors, and input cables of the motor respectively penetrate through the 3 paths of current sensors.

Preferably, the three-phase full-bridge inverter circuit comprises a series capacitor formed by a capacitor C1 and a capacitor C2, and a topology structure formed by 6 IGBTs, wherein the 6 IGBTs are S1, S2, S3, S4, S5 and S6 respectively; the collector of S4 is connected with the emitter of S1, the collector of S5 is connected with the emitter of S2, the collector of S6 is connected with the emitter of S3, the emitters of S1, S2 and S3 are respectively connected with the three-phase input terminal of the motor through cables, the collectors of S1, S2 and S3 are respectively connected with the cathode of a rectifier bridge, the emitters of S4, S5 and S6 are respectively connected with the anode of the rectifier bridge, and the IGBT gate level signals g of S1, S2, S3, S4, S5 and S6 are respectively connected with the g output signal of the core controller.

Preferably, the energy storage circuit includes four energy storage branches connected in parallel, which are respectively: the capacitor C3 is connected with the capacitor C4 in series, the capacitor C3 is connected with the resistor R3 in parallel, and the capacitor C4 is connected with the resistor R4 in parallel to form a first energy storage branch; a capacitor C5 is connected with a capacitor C6 in series, a capacitor C5 is connected with a resistor R5 in parallel, and a capacitor C6 is connected with a resistor R6 in parallel to form a second energy storage branch; a capacitor C7 is connected with a capacitor C8 in series, a capacitor C7 is connected with a resistor R7 in parallel, and a capacitor C8 is connected with a resistor R8 in parallel to form a third energy storage branch; the capacitor C9 is connected in series with the capacitor C10, the capacitor C9 is connected in parallel with the resistor R9, and the capacitor C10 is connected in parallel with the resistor R10 to form a fourth energy storage branch.

Preferably, the voltage sensor is a feedthrough voltage sensor, and the current sensor is a feedthrough current sensor.

Preferably, the capacitance selection in the energy storage circuit is calculated according to the following formula:

wherein m is the mass of the slider; v is the average speed of the slide from bottom dead center to top dead center; c is the total capacitance value of the energy storage circuit; and delta U is the difference value of the DC bus voltage.

The invention also comprises a protection method of the servo press, which comprises the following steps:

the method comprises the following steps: the voltage of a three-phase 380V power line is connected to the three-phase input side of the rectifier bridge, when the amplitude of a single-phase 220V voltage is in a positive half cycle, the diode D1 is conducted, the capacitor in the three-phase full-bridge inverter circuit is charged through the soft start circuit B, and when the voltage between the positive and negative of the direct-current bus reaches 540V, the capacitor is not charged continuously;

step two: the DC-DC power supply module converts 540V into 24V, supplies power to the core controller, and the core controller sends an instruction to the rectifier bridge;

step three: the rectifier bridge receives an instruction of a core controller to start working, and rectifies the three-phase 380V alternating voltage into 540V direct voltage; the 540V dc voltage forms two branches: one branch is used for charging the energy storage circuit through the soft start circuit A until the voltage is fully charged to 540V, so that the thyristor S7 is not switched on; the other branch circuit is used for providing direct-current voltage for the three-phase full-bridge inverter circuit;

step four: the core controller receives a press machine control instruction, starts to execute the press machine control instruction, and simultaneously outputs a pulse-width modulation (PWM) wave g signal to an Insulated Gate Bipolar Transistor (IGBT) gate-level signal g of the three-phase full-bridge inverter circuit by combining the feedback of a current sensor signal;

step five: after the IGBT of the three-phase full-bridge inverter circuit receives the gate-level signal g, the IGBT starts to execute switching action, the power supply is from the output voltage of the rectifier bridge, and the motor starts to rotate; in the working process of the motor, if the three-phase 380V power line is suddenly powered off, executing the step six;

step six: the three-phase 380V power line input by the rectifier bridge is suddenly cut off, the voltage sensor feeds back a voltage signal to the core controller in real time, the core controller immediately stores the current power grid voltage value into an EEPROM (electrically erasable programmable read-only memory) in the core controller, and the power grid voltage at the moment disappears to be regarded as a fault and is stored into a fault storage area FLASH in the core controller; the core controller enables the thyristor S7 to be conducted, the energy storage circuit provides input power for the DC-DC power supply module and continuously supplies power for the core controller, the motor controls the sliding block to stop emergently, and the sliding block is enabled to return to the top dead center position from any current position by controlling the motor;

step seven: when the motor returns to the top dead center, the control thyristor S7 is not conducted any more, and no energy is provided for the motor any more, so that the whole safety protection process is completed.

The protection device of the invention ensures that the servo press does not need to be provided with a brake, when the 3-phase 380V power supply in normal operation disappears suddenly, the controllable safe operation of the motor can still be ensured, and the short-time working power supply is provided for the motor of the servo press, so that the slide block stops emergently at the current position, and immediately returns to the top dead center and stops. Compared with the situation that the motor is uncontrollably and freely rotates when the motor is suddenly powered off, the protection device greatly protects the die and the production workpiece, is safe and reliable, and has a great application prospect in the actual working condition. Meanwhile, compared with the installation brake, the size of the installation space of the motor is not increased, the price is reduced by about 70 percent compared with the installation brake, and the cost is greatly saved.

Drawings

Fig. 1 is a schematic circuit diagram of an embodiment of the present invention.

FIG. 2 is a control flow chart according to an embodiment of the present invention.

In the figure, 1 a soft start circuit A, 2 a soft start circuit B, 3 a three-phase full-bridge inverter circuit and 4 an energy storage circuit.

Detailed Description

The following embodiments of the present invention are provided, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are within the protection scope of the present invention.

The circuit schematic diagram of the protection device is shown in figure 1, and comprises a rectifier bridge, a soft start circuit A1, a soft start circuit B2, an energy storage circuit 4, a three-phase full-bridge inverter circuit 3 and a core controller.

The soft start circuit A1 comprises a soft start resistor R1 and a soft start resistor R2, wherein the soft start resistor R1 is connected with the soft start resistor R2 in parallel.

The soft start circuit B2 comprises a soft start resistor R11 and a soft start resistor R12, wherein the soft start resistor R11 is connected with the soft start resistor R12 in parallel.

The three-phase full-bridge inverter circuit 3 includes a capacitor and an IGBT (Insulated Gate Bipolar Transistor). The three-phase full-bridge inverter circuit 3 in the present embodiment includes a series capacitor formed by a capacitor C1 and a capacitor C2, and a topology structure formed by 6 IGBTs, where the 6 IGBTs are S1, S2, S3, S4, S5, and S6, a collector of S4 is connected to an emitter of S1, a collector of S5 is connected to an emitter of S2, and a collector of S6 is connected to an emitter of S3. Emitters of S1, S2 and S3 are respectively connected with three-phase input terminals of the motor through cables, and IGBT gate-level signals g of S1, S2, S3, S4, S5 and S6 are connected with g output signals of the core controller. Collectors of S1, S2 and S3 are respectively connected with a cathode of the rectifier bridge, and emitters of S4, S5 and S6 are respectively connected with an anode of the rectifier bridge.

The energy storage circuit 4 comprises a plurality of energy storage branches, the plurality of energy storage branches are connected in parallel, each energy storage branch is connected with a plurality of capacitors in series, and each capacitor is connected with a resistor in parallel. In this embodiment, four energy storage branches are connected in parallel to form the energy storage circuit 4, which is respectively: the capacitor C3 is connected with the capacitor C4 in series, the capacitor C3 is connected with the resistor R3 in parallel, and the capacitor C4 is connected with the resistor R4 in parallel to form an energy storage branch; the capacitor C5 is connected with the capacitor C6 in series, the capacitor C5 is connected with the resistor R5 in parallel, and the capacitor C6 is connected with the resistor R6 in parallel to form an energy storage branch; the capacitor C7 is connected with the capacitor C8 in series, the capacitor C7 is connected with the resistor R7 in parallel, and the capacitor C8 is connected with the resistor R8 in parallel to form an energy storage branch; the capacitor C9 is connected with the capacitor C10 in series, the capacitor C9 is connected with the resistor R9 in parallel, and the capacitor C10 is connected with the resistor R10 in parallel to form an energy storage branch. The selection of the capacitance in the tank circuit 4 can here be based on the law of conservation of energy:

wherein m is the mass of the slider; v is the average speed of the slide from bottom dead center to top dead center; c is the total capacitance of the tank circuit 4; the delta U is a direct current bus voltage difference value, a normal direct current bus voltage value is 540V, the lowest working value of the general direct current bus voltage is 480V, the difference value of the two voltage values is 60V, and therefore the delta U is selected to be 60V according to an empirical value.

The core controller includes CPU, FLASH, EEPROM and reset circuit.

In FIG. 1, a 3-phase 380V power line is connected with the input of a rectifier bridge, a single-phase 220V power line is connected with the anode of a diode D1, and the cathode of a diode D1 is connected with the cathode of the rectifier bridge. The cathode of the rectifier bridge is connected with one end of a soft start circuit A1 formed by connecting soft start resistors R1 and R2 in parallel, and the other end of the soft start circuit A1 is connected with the anode of a thyristor S7. One end of a soft start circuit B2 formed by connecting soft start resistors R11 and R12 in parallel is connected with the anode of a capacitor C1, the cathode of a thyristor S7 is connected with the anode of a capacitor C1, a capacitor C1 is connected with the capacitor C2 in series, and the cathode of the capacitor C2 is connected with the anode of a rectifier bridge. The anode of the tank circuit 4 is connected to the anode of the thyristor S7, and the cathode of the tank circuit 4 is connected to the anode of the rectifier bridge. The cathode of the thyristor S7 is connected to the input of the DC-DC power module, and the output of the DC-DC power module is connected to the power supply of the core controller. Emitters of S1, S2 and S3 are respectively connected with three-phase input terminals of the motor through cables, IGBT gate level signals g of S1, S2, S3, S4, S5 and S6 are connected with g output signals of the core controller, and an output shaft of the motor is connected with a crank connecting rod transmission mechanism of the press. The press control commands are input into the core controller. Cables of a three-phase 380V power line respectively penetrate through the 3 voltage sensors, an input cable of the three-phase motor respectively penetrates through the 3 current sensors, voltage signals collected by the 3 paths of voltage sensors are input to the core controller, and current signals of the 3 paths of current sensors are input to the core controller.

Based on the protection device of the servo press machine, a protection method is realized by adopting the following specific steps, and the protection method is shown in the attached figure 2:

the method comprises the following steps: the voltage of a three-phase 380V power line is connected to the three-phase input side of the rectifier bridge, the diode D1 is conducted, when the amplitude of the single-phase 220V voltage is in a positive half cycle, the capacitors C1 and C2 are charged through the soft starting resistors R11 and R12, and the direct-current bus is not charged continuously when the voltage between the positive side and the negative side reaches 540V.

Step two: the DC-DC power supply module converts 540V into 24V to supply power to the core controller, and the core controller sends an instruction to the rectifier bridge.

Step three: the rectifier bridge receives an instruction of a core controller to start working, and rectifies the three-phase 380V alternating voltage into 540V direct voltage; the core controller can detect the voltage value of the direct current bus through an internal circuit; the 540V dc voltage forms two branches: one branch is to charge the energy storage circuit 4 through a soft start resistor R1 and a soft start resistor R2 until the voltage is fully charged to 540V, and a thyristor S7 is not switched on from power-up to the step; the other branch is used for providing direct-current voltage for the three-phase full-bridge inverter circuit 3.

Step four: the core controller can receive input signals such as a press control command and the like at the moment, starts to execute a control command, and simultaneously, in combination with the feedback of the current sensor signal, the CPU of the core controller starts to operate a motor control algorithm and outputs a PWM wave g signal to 6 paths of IGBT gate-level signals g of S1, S2, S3, S4, S5 and S6.

Step five: when the IGBTs of S1 to S6 receive the gate-level signal g, the switching operation is started, the output voltage from the rectifier bridge is supplied, and the motor starts to rotate. And if sudden power failure occurs, executing the following step six.

Step six: if the three-phase 380V power line input by the rectifier bridge is suddenly cut off for some reason, the direct-current bus voltage cannot suddenly drop due to the existence of the capacitor C1 and the capacitor C2. The 3-path voltage sensor feeds back a power grid voltage signal to the core controller in real time, and the core controller immediately performs the following actions: saving the current power grid voltage value into an EEPROM, considering the power grid voltage loss at the moment as a fault, and storing the fault into a fault storage area FLASH; the core controller controls to turn on the thyristor S7, and at this time, the energy storage circuit 4 formed by the capacitor C3 to the capacitor C10 provides input power for the DC-DC power supply module and continuously supplies power for the core controller. The energy previously stored in the capacitors C3 to C10 may provide electric power to the motor for a certain time, so that the motor can control the slider to stop emergently and the slider is returned to the top dead center position from any current position by controlling the motor.

Step seven: when the motor returns to the top dead center, the thyristor S7 is closed, no energy is supplied to the motor any more, and the whole safety protection process is completed.

The motor control algorithm comprises the contents of motor current and speed data processing, Clarke and Park conversion, magnetic field orientation control, loss control, PWM wave calculation and the like. The internal control strategy of the core controller comprises the power failure protection control strategy besides a conventional motor control algorithm and a conventional motor control function.

The above-described embodiment is only one of the preferred embodiments of the present invention, and general changes and substitutions by those skilled in the art within the technical scope of the present invention are included in the protection scope of the present invention.