Controllable rectification inverter power supply system for steel rail flash welding

Abstract

The utility model relates to the technical field of steel rail flash welding, in particular to a steel rail flash welding controllable rectification inverter power supply system which comprises a power supply input circuit, a three-phase-single-phase controllable rectification inverter circuit, a load circuit, a control and drive circuit and a signal given circuit. The power supply input circuit is connected with the three-phase-single-phase controllable rectification inverter circuit, the three-phase-single-phase controllable rectification inverter circuit is connected with the load circuit and the control and drive circuit, and the control and drive circuit is connected with the signal given circuit. According to the utility model, a three-phase half-controlled rectification mode is adopted for rectification, and compared with an uncontrolled rectification mode, the conduction angle of the thyristor can be controlled, and especially in the just starting stage of a power supply, the control is carried out by slowly increasing the conduction angle of the thyristor, so that the direct-current voltage at the direct-current side of the energy-storage capacitor is slowly increased; the problem that the impact current on the capacitor, the rectifying element and the external power supply end is too large at the starting moment can be effectively avoided, and the element is prevented from being damaged.

Description

Technical Field

[0001] The utility model relates to the technical field of rail flash welding, in particular to a controllable rectifier inverter power supply system for rail flash welding. Background Art

[0002] Rail flash welding plays an important role in modern railway construction and is widely used in the connection of rail seamless lines. Flash welding uses two metal workpieces to make contact. During the contact process, the electrode and the workpiece form a path, and the current flows through it to heat the workpiece, so that part of the workpiece melts to form liquid metal. After heating for a certain period of time, a certain pressure is applied to the joint, and it is cooled to form a solid weld.

[0003] At present, most rail flash welders use three-phase input for power supply, and the power generation (power supply) system is a three-phase load. The main welding load is a single-phase load, that is, the AC welder is a single-phase asymmetric power load, and the voltage required during the welding process is regulated by the thyristor. This load will cause a three-phase unbalanced load during the welding process, a pulsating load, a high current peak, instantaneous overload of the generator, and black smoke, which is not friendly to the environment; asymmetric load operation causes a neutral point offset, low power utilization efficiency, and energy waste, etc.

[0004] Existing technologies such as CN103457487A, CN202356781U and CN202356781U, among which the first one is the bidirectional thyristor voltage regulation used by most of the current rail flash welding to control the voltage during welding; the second one is to invert the three-phase electricity after passing through the three-phase fully controlled rectifier circuit and then through the capacitor filtering, and the AC square wave obtained after inversion is also required to pass through the DC isolation capacitor C before being transmitted to the welding transformer; the third one is the flash welding variable frequency power supply system, which uses the three-phase uncontrolled rectification method, in which the capacitor mainly plays the role of filtering, and the AC power obtained after the inverter is the AC power of variable frequency (corresponding to the required frequency). The above patents still do not solve the problems existing in the above existing technologies. Summary of the invention

[0005] In view of the deficiencies in the prior art, the utility model provides a rail flash welding rectifier inverter power supply and a control system thereof, which can well solve a series of problems caused by the prior art rail flash welding power supply system using two-phase input.

[0006] In order to achieve the above technical effects, the technical solution of this application is as follows:

[0007] A rail flash welding controlled rectifier inverter power supply system comprises a power input circuit, a three-phase-single-phase controlled rectifier inverter circuit, a load circuit, a control and drive circuit and a signal setting circuit; the power input circuit is connected to the three-phase-single-phase controlled rectifier inverter circuit, the three-phase-single-phase controlled rectifier inverter circuit is connected to the load circuit and the control and drive circuit, and the control and drive circuit is connected to the signal setting circuit.

[0008] Furthermore, the power input circuit is connected to a three-phase generator set.

[0009] Furthermore, the three-phase-single-phase controlled rectifier inverter circuit includes a three-phase controlled rectifier circuit, a capacitor filter energy storage circuit and an inverter circuit, the input end of the three-phase controlled rectifier circuit is connected to the output end of the power input circuit, the capacitor filter energy storage circuit is connected to the output end of the three-phase controlled rectifier circuit, and the inverter circuit input end is connected to the output end of the capacitor filter energy storage circuit.

[0010] Further, the inverter circuit includes: a first IGBT tube T1, a second IGBT tube T2, a third IGBT tube T3, a fourth IGBT tube T4, a fifth IGBT tube T5, a sixth IGBT tube T6, a seventh IGBT tube T7, and an eighth IGBT tube T8; the collector of the first IGBT tube T1, the collector of the third IGBT tube T3, the collector of the fifth IGBT tube T5, and the collector of the seventh IGBT tube T7 are connected to the positive output end of the capacitor filter, the emitter of the second IGBT tube T2, the emitter of the fourth IGBT tube T4, the emitter of the sixth IGBT tube T6, and the emitter of the eighth IGBT tube T8 are connected to the negative output end of the capacitor filter, and the gate of the first IGBT tube T1, the gate of the third IGBT tube T3, the collector of the fifth IGBT tube T5, and the collector of the seventh IGBT tube T7 are connected to the positive output end of the capacitor filter, and the emitter of the second IGBT tube T2, the emitter of the fourth IGBT tube T4, the emitter of the sixth IGBT tube T6, and the emitter of the eighth IGBT tube T8 are connected to the negative output end of the capacitor filter. The gate of the transistor T3, the gate of the sixth IGBT transistor T6, and the gate of the eighth IGBT transistor T8 are connected to the first output end of the inverter drive circuit; the gate of the second IGBT transistor T2, the gate of the fourth IGBT transistor T4, the gate of the fifth IGBT transistor T5, and the gate of the seventh IGBT transistor T7 are connected to the second output end of the inverter drive circuit; the emitter of the first IGBT transistor T1 and the emitter of the third IGBT transistor T3 are connected to the collector of the second IGBT transistor T2 and the collector of the fourth IGBT transistor T4 to form the first output end of the inverter circuit; the emitter of the fifth IGBT transistor T5 and the emitter of the seventh IGBT transistor T7 are connected to the collector of the sixth IGBT tube T6 and the collector of the eighth IGBT tube T6 to form the second output end of the inverter circuit.

[0011] Further, the three-phase controlled rectifier circuit includes: a first diode D1, a second diode D3, a third diode D5, a first thyristor D2, a second thyristor D4, and a third thyristor D6; the anode of the first diode D1 and the cathode of the first thyristor D2 are connected to the A-phase output terminal of the power input circuit 110, the anode of the second diode D3 and the cathode of the second thyristor D4 are connected to the B-phase output terminal of the power input circuit 110, the anode of the third diode D5 and the cathode of the third thyristor D6 are connected to the A-phase output terminal of the power input circuit 110, The first thyristor D2, the second thyristor D4, and the third thyristor D3 are connected to the output end of the control circuit; the cathode of the first diode D1, the cathode of the second diode D3, and the cathode of the third diode D5 are respectively connected to the positive input end of the capacitor filter tank circuit; the anode of the first thyristor D2, the anode of the second thyristor D3, and the anode of the third thyristor D5 are respectively connected to the negative input end of the capacitor filter tank circuit; the control electrode of the first thyristor D2, the control electrode of the second thyristor D4, and the control electrode of the third thyristor D3 are connected to the output end of the control circuit.

[0012] Furthermore, the load circuit includes two welding transformers, which are connected in parallel, and the primary sides of the two welding transformers are connected to the output end of the inverter circuit in the three-phase-single-phase controlled rectifier inverter circuit, and the secondary sides of the two welding transformers are respectively connected to the dynamic clamp and the static clamp.

[0013] Furthermore, the control and drive circuit is connected to the IGBT of the inverter circuit in the three-phase-single-phase controlled rectifier inverter circuit.

[0014] Furthermore, the drive and control circuit includes a Hall voltage sensor, a Hall current sensor, a drive circuit, a current zero-crossing detection circuit, a precision rectifier and filter circuit, and a DSP chip; the input end of the Hall voltage sensor is connected to the output end of the capacitor filter rectifier circuit and to the input end of the inverter circuit, the output end of the Hall voltage sensor is connected to the ADC end of the DSP chip, the input end of the drive circuit is connected to the ePWM end of the DSP chip, and the output end of the drive circuit is connected to the IGBT of the inverter circuit; the output end of the inverter circuit is connected to the input end of the Hall current sensor, the output end of the Hall current sensor is connected to the input end of the current zero-crossing detection circuit and to the input end of the precision rectifier and filter circuit; the output end of the current zero-crossing detection circuit is connected to the eCAP end of the DSP chip, and the ePWM input end of the DSP chip is connected to the eCAP input end of the DSP chip; the output end of the precision rectifier and filter circuit is connected to the ADC end of the DSP chip; the PLC of the signal given circuit is connected to the SCI end of the DSP chip.

[0015] Furthermore, the DSP chip is TMS320F28335.

[0016] The technical principle of this utility model:

[0017] The utility model inputs three-phase alternating current into a three-phase half-controlled rectifier for rectification into direct current, which is then inverted into alternating current with a fixed frequency of 50 Hz and adjustable voltage by an inverter, and is controlled by a PLC to obtain a desired single-phase alternating current with a fixed frequency of 50 Hz and a size corresponding to the fixed frequency of 50 Hz to supply the welding machine for welding.

[0018] The advantages of the utility model are:

[0019] The utility model adopts a three-phase half-controlled rectification method for rectification. Compared with uncontrolled rectification, it can control the conduction angle of the thyristor, especially in the startup stage of the power supply. It controls by slowly increasing the conduction angle of the thyristor, so that the DC voltage on the DC side of the energy storage capacitor increases slowly, which can effectively avoid the problem of excessive impact current on the capacitor, rectification element and external power supply end at the moment of startup, and avoid damage to the components.

[0020] The inverter control circuit provided by the utility model adopts a PWM control adjustment method to adjust the duty cycle of the PWM wave so as to adjust the voltage value of the inverter power supply well. The PLC control output corresponds to a given signal value to control the voltage value required for welding, and a sine wave with stable frequency modulation can be obtained, thus avoiding the voltage fluctuation problem during two-phase input.

[0021] The large energy storage capacitor provided by the utility model can charge and discharge electric energy at the peak and valley values ​​of the current during welding, and complete the storage and release of energy. It not only filters the rectified voltage but also completes the function of peak shaving and valley filling. While achieving three-phase balanced power consumption, it avoids the problem of black smoke caused by incomplete diesel combustion due to instantaneous overload of the generator during the peak current period, and is environmentally friendly.

[0022] The power supply system provided by the utility model ensures welding quality while avoiding the large capacity of the generator, reduces oil consumption and also reduces production costs, and can well save energy.

[0023] The utility model is a controllable rectifier inverter power supply system. The rectifier used is a three-phase controllable rectifier bridge module composed of thyristors and diodes. When the power supply is started, the conduction angle of the thyristor is controlled to increase slowly. After the power supply is started, the conduction angle is adjusted to the maximum. The welding voltage is not adjusted by using thyristors, and three-phase full-controlled rectification and three-phase uncontrolled rectification are not used. The large-capacity capacitor used in the utility model not only filters the waveform after rectification, but also has the function of large-capacity energy storage. The current peak and valley values ​​during welding are charged and discharged to replenish energy and reduce the instantaneous overload of the generator. The inverter circuit used in the utility model is mainly controlled by PWM waves to open and close, and a single-phase alternating current with a corresponding amplitude and a power frequency of 50Hz is obtained. It does not need to be transmitted to the welding transformer after passing through the isolation capacitor. The single-phase alternating current of the utility model after inversion is directly transmitted to the welding transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the utility model.

[0025] Figure 2 It is a circuit diagram of the utility model.

[0026] In the attached drawings: 110 - power input circuit 110, 120 - three-phase to single-phase controlled rectifier inverter circuit, 130 - load circuit, 140 - control and drive circuit, 150 - signal setting circuit. DETAILED DESCRIPTION

[0027] Example 1

[0028] like Figure 1 As shown, a rail flash welding controlled rectifier inverter power supply system includes a power input circuit 110, a three-phase-single-phase controlled rectifier inverter circuit 120, a load circuit 130, a control and drive circuit 140 and a signal setting circuit 150; the power input circuit 110 is connected to the three-phase-single-phase controlled rectifier inverter circuit 120, the three-phase-single-phase controlled rectifier inverter circuit 120 is connected to the load circuit 130 and the control and drive circuit 140, and the control and drive circuit 140 is connected to the signal setting circuit 150. The utility model adopts a three-phase half-controlled rectification method for rectification. Compared with uncontrolled rectification, it can control the conduction angle of the thyristor, especially in the initial startup stage of the power supply, by slowly increasing the conduction angle of the thyristor, so that the DC voltage on the DC side of the energy storage capacitor increases slowly, which can effectively avoid the problem of excessive impact current on the capacitor, the rectifier element and the external power supply end at the moment of startup, and avoid damage to the components.

[0029] Example 2

[0030] like Figure 1As shown, a rail flash welding controlled rectifier inverter power supply system includes a power input circuit 110, a three-phase-single-phase controlled rectifier inverter circuit 120, a load circuit 130, a control and drive circuit 140 and a signal given circuit 150; the power input circuit 110 is connected to the three-phase-single-phase controlled rectifier inverter circuit 120, the three-phase-single-phase controlled rectifier inverter circuit 120 is connected to the load circuit 130 and the control and drive circuit 140, and the control and drive circuit 140 is connected to the signal given circuit 150.

[0031] The power input circuit 110 is connected to the three-phase diesel generator set and is used for power input of the three-phase AC-DC rectifier circuit.

[0032] The three-phase-single-phase controlled rectifier inverter circuit 120 includes a three-phase controlled rectifier circuit, a capacitor filter energy storage circuit and an inverter circuit. The input end of the three-phase controlled rectifier circuit is connected to the output end of the power input circuit 110, and is used to rectify the three-phase alternating current generated by the diesel generator (or external power supply) to form direct current. The capacitor filter energy storage circuit is connected to the output end of the three-phase controlled rectifier circuit, and is used to use the capacitor energy storage to supplement the energy of each pulse current at the peak current during welding, and to charge at the trough of the welding current, so as to make the voltage of the DC bus smoother while filtering. The input end of the inverter circuit is connected to the output end of the capacitor filter energy storage circuit, and is used to invert the DC power into the single-phase fixed-frequency alternating current required for welding.

[0033] The inverter circuit includes: a first IGBT tube T1, a second IGBT tube T2, a third IGBT tube T3, a fourth IGBT tube T4, a fifth IGBT tube T5, a sixth IGBT tube T6, a seventh IGBT tube T7, and an eighth IGBT tube T8; the first IGBT tube T1 collector, the third IGBT tube T3 collector, the fifth IGBT tube T5 collector, and the seventh IGBT tube T7 collector are connected to the positive output end of the capacitor filter, the second IGBT tube T2 emitter, the fourth IGBT tube T4 emitter, the sixth IGBT tube T6 emitter, and the eighth IGBT tube T8 emitter are connected to the negative output end of the capacitor filter, the first IGBT tube T1 gate, the third IGBT tube T3 gate The gate of the sixth IGBT tube T6 and the gate of the eighth IGBT tube T8 are connected to the first output end of the inverter drive circuit; the gate of the second IGBT tube T2, the gate of the fourth IGBT tube T4, the gate of the fifth IGBT tube T5 and the gate of the seventh IGBT tube T7 are connected to the second output end of the inverter drive circuit; the emitter of the first IGBT tube T1 and the emitter of the third IGBT tube T3 are connected to the collector of the second IGBT tube T2 and the collector of the fourth IGBT tube T4 to form the first output end of the inverter circuit; the emitter of the fifth IGBT tube T5 and the emitter of the seventh IGBT tube T7 are connected to the collector of the sixth IGBT tube T6 and the collector of the eighth IGBT tube T6 to form the second output end of the inverter circuit.

[0034] The three-phase controlled rectifier circuit includes: a first diode D1, a second diode D3, a third diode D5, a first thyristor D2, a second thyristor D4, and a third thyristor D6; the anode of the first diode D1 and the cathode of the first thyristor D2 are connected to the A-phase output end of the power input circuit 110110, the anode of the second diode D3 and the cathode of the second thyristor D4 are connected to the B-phase output end of the power input circuit 110110, the anode of the third diode D5 and the cathode of the third thyristor D6 are connected to the power input circuit 110110, and the cathode of the third thyristor D6 is connected to the power input circuit 110110. The cathode of the first diode D1, the cathode of the second diode D3 and the cathode of the third diode D5 are respectively connected to the positive input terminal of the capacitor filter energy storage circuit, and the anode of the first thyristor D2, the anode of the second thyristor D3 and the anode of the third thyristor D5 are respectively connected to the negative input terminal of the capacitor filter energy storage circuit; the control electrode of the first thyristor D2, the control electrode of the second thyristor D4 and the control electrode of the third thyristor D3 are connected to the output terminal of the control circuit.

[0035] The load circuit 130 includes two welding transformers, which are connected in parallel. The primary sides of the two welding transformers are connected to the output end of the inverter circuit in the three-phase-single-phase controlled rectifier inverter circuit 120, and the secondary sides of the two welding transformers are connected to the moving clamp and the static clamp respectively.

[0036] The control and drive circuit 140 is connected to the IGBT of the inverter circuit in the three-phase-single-phase controlled rectifier inverter circuit 120, and sends out a PWM wave to control the on and off of the IGBT, and finally controls the magnitude of the voltage value output by the inverter circuit.

[0037] like Figure 2 As shown, the drive and control circuit includes a Hall voltage sensor, a Hall current sensor, a drive circuit, a current zero-crossing detection circuit, a precision rectifier filter circuit and a DSP chip; the input end of the Hall voltage sensor is connected to the output end of the capacitor filter rectifier circuit and to the input end of the inverter circuit, the output end of the Hall voltage sensor is connected to the ADC end of the DSP chip, the input end of the drive circuit is connected to the ePWM end of the DSP chip, and the output end of the drive circuit is connected to the IGBT of the inverter circuit; the output end of the inverter circuit is connected to the input end of the Hall current sensor, the output end of the Hall current sensor is connected to the input end of the current zero-crossing detection circuit and to the input end of the precision rectifier filter circuit; the output end of the current zero-crossing detection circuit is connected to the eCAP end of the DSP chip, the ePWM input end of the DSP chip is connected to the eCAP input end of the DSP chip; the output end of the precision rectifier filter circuit is connected to the ADC end of the DSP chip; the PLC of the signal given circuit 150 is connected to the SCI end of the DSP chip. The DSP chip is TMS320F28335.

[0038] The utility model adopts a three-phase half-controlled rectification method for rectification. Compared with uncontrolled rectification, it can control the conduction angle of the thyristor, especially in the startup stage of the power supply. It controls by slowly increasing the conduction angle of the thyristor, so that the DC voltage on the DC side of the energy storage capacitor increases slowly, which can effectively avoid the problem of excessive impact current on the capacitor, rectification element and external power supply end at the moment of startup, and avoid damage to the components.

[0039] The inverter control circuit provided by the utility model adopts a PWM control adjustment method to adjust the duty cycle of the PWM wave so as to adjust the voltage value of the inverter power supply well. The PLC control output corresponding current value is used to control the voltage value required for welding, so as to obtain a stable and continuous sine wave and avoid the voltage fluctuation problem during two-phase input.

[0040] The large energy storage capacitor provided by the utility model can charge and discharge electric energy at the peak and valley values ​​of the current during welding, and complete the storage and release of energy. It not only filters the rectified voltage but also completes the function of peak shaving and valley filling. While achieving the working balance of three-phase electricity, it avoids the problem of black smoke caused by incomplete diesel combustion due to instantaneous overload of the generator during the peak current period, and is environmentally friendly.

[0041] The power supply system provided by the utility model ensures welding quality while avoiding the large capacity of the generator, reduces oil consumption and also reduces production costs, and can well save energy.

[0042] The utility model is a controllable rectifier inverter power supply system. The rectifier used is a three-phase controlled rectifier bridge module composed of thyristors and diodes. The conduction angle of the thyristors can be controlled. It does not use thyristors for voltage regulation, nor does it use three-phase full-controlled rectification and three-phase uncontrolled rectification. The utility model uses a large-capacity capacitor. In addition to filtering the waveform after rectification, it also has the function of large-capacity energy storage. It charges and discharges the current peak and valley values ​​during welding, replenishes energy, and reduces the instantaneous overload of the generator. The inverter circuit used in the utility model is mainly controlled by PWM waves to open and close, and obtains a single-phase alternating current with a corresponding amplitude and an industrial frequency of 50Hz. It does not need to be transmitted to the welding transformer after passing through a separation capacitor. The single-phase alternating current of the utility model after inversion is directly transmitted to the welding transformer.

[0043] Example 3

[0044] Figure 1 FIG. 1 is a structural diagram of a rail flash welding controllable rectifier inverter power supply system provided by an embodiment of the utility model, as shown in FIG. Figure 1 As shown, the rail flash welding controllable rectifier inverter power supply system 100 provided in this embodiment specifically includes:

[0045] A power input circuit 110, a three-phase to single-phase controllable rectifier inverter circuit 120, a load circuit 130, a control and drive circuit 140, and a signal setting circuit 150;

[0046] The input end of the power input current 110 is connected to the three-phase alternating current output by the diesel generator set, and is used to input the three-phase alternating current output by the diesel generator set into the rail flash welding rectifier inverter power supply and its control system 100 through the power input circuit 110;

[0047] The three-phase-single-phase controlled rectifier inverter circuit 120 includes a three-phase controlled rectifier circuit, a capacitor filter energy storage circuit, and an inverter circuit. The input end of the controlled rectifier circuit is connected to the output end of the power input circuit, and is used to rectify the three-phase AC output of the power input circuit into DC. The input end of the capacitor filter energy storage circuit is connected to the output end of the three-phase controlled rectifier circuit, and is used to filter the rectified DC, and store the excess electric energy at the peak of the welding current, and discharge it at the valley value. The input end of the inverter circuit is connected to the output end of the capacitor filter energy storage circuit, and is used to convert the filtered DC into the industrial frequency single-phase AC required for welding.

[0048] The load circuit 130 includes two welding transformers, a movable clamp, and a static clamp. The two welding transformers are connected in parallel, the primary sides of the two welding transformers are connected to the output end of the inverter circuit, and the secondary sides are connected to the movable clamp and the static clamp respectively;

[0049] The driving and control circuit 140 includes a driving circuit and a control circuit. The driving circuit is connected to the control circuit, and the other end is connected to the IGBT of the inverter circuit to control the on and off of the IGBT and invert the DC power into single-phase AC power.

[0050] A part of the signal setting circuit 150 is connected to the PLC for 485 communication, and another part receives a 4-20mA current signal from the PLC to control the voltage value output by the inverter circuit.

[0051] The utility model inputs the three-phase alternating current output by the diesel generator set into the controllable rectifier through the power input circuit, rectifies the three-phase alternating current into direct current by slowly increasing the conduction angle of the thyristor, filters the direct current into relatively smooth and stable direct current through the capacitor filtering energy storage circuit, and then converts it into industrial frequency single-phase alternating current of different amplitudes through the inverter circuit; then supplies power to the moving fixture and the static fixture through the welding transformer, and the user can input the welding voltage required by the welding machine into the PLC according to the upper computer, and then the PLC performs conversion and outputs the corresponding 4-20mA current, which is written into the TMS320F28335 chip through the signal given circuit, and then sends out the corresponding PWM wave to control the opening and closing of the IGBT through the control and drive circuit to obtain the single-phase alternating current of the corresponding voltage.

[0052] The rail flash welding controllable rectifier inverter power supply system provided by the utility model converts three-phase alternating current into single-phase alternating current after three-phase-to-single-phase rectification and inversion, thereby changing the three-phase power imbalance problem caused by the traditional three-phase two-phase power supply, improving the power factor, and at the same time adopting large-capacity capacitors for charging and discharging energy storage, thereby improving the utilization efficiency of the power supply, making the generator set run more smoothly, the diesel burns more fully, the emission of toxic gases is reduced, and the total power of the system distribution is reduced, which can better save energy and reduce emissions and reduce costs.

[0053] The three-phase-single-phase controlled rectifier inverter circuit of this embodiment is composed of a controlled rectifier circuit, a capacitor filter energy storage circuit, and an inverter circuit. Its function is to convert the three-phase AC output by the diesel generator set into the single-phase industrial frequency AC required by the welding machine. When the welding load decreases instantaneously, the excess electric energy provided by the diesel generator set is charged and stored through the large-capacity capacitor; when the welding load increases instantaneously, the large-capacity capacitor can discharge the energy previously charged and stored to make up for the generator set's inability to provide instantaneous current, playing a role of peak shaving and valley filling, thereby reducing the impact of the load on the operation of the generator set, improving the stability of the generator set during operation, and also reducing the emission of black smoke and protecting the environment.

[0054] In the practical embodiment, the inverter circuit includes: a first IGBT tube T1, a second IGBT tube T2, a third IGBT tube T3, a fourth IGBT tube T4, a fifth IGBT tube T5, a sixth IGBT tube T6, a seventh IGBT tube T7, and an eighth IGBT tube T8; the first IGBT tube T1 collector, the third IGBT tube T3 collector, the fifth IGBT tube T5 collector, and the seventh IGBT tube T7 collector are connected to the positive output end of the capacitor filter, the second IGBT tube T2 emitter, the fourth IGBT tube T4 emitter, the sixth IGBT tube T6 emitter, and the eighth IGBT tube T8 emitter are connected to the negative output end of the capacitor filter, and the first IGBT tube T1 gate, the third IGBT tube T3 collector, the fifth IGBT tube T5 collector, and the seventh IGBT tube T7 collector are connected to the positive output end of the capacitor filter, and .... The gate of the BT tube T3, the gate of the sixth IGBT tube T6, and the gate of the eighth IGBT tube T8 are connected to the first output end of the inverter drive circuit; the gate of the second IGBT tube T2, the gate of the fourth IGBT tube T4, the gate of the fifth IGBT tube T5, and the gate of the seventh IGBT tube T7 are connected to the second output end of the inverter drive circuit; the emitter of the first IGBT tube T1 and the emitter of the third IGBT tube T3 are connected to the collector of the second IGBT tube T2 and the collector of the fourth IGBT tube T4 to form the first output end of the inverter circuit; the emitter of the fifth IGBT tube T5 and the emitter of the seventh IGBT tube T7 are connected to the collector of the sixth IGBT tube T6 and the collector of the eighth IGBT tube T6 to form the second output end of the inverter circuit.

[0055] The inverter circuit of this embodiment adopts 4 groups of IGBTs, which are connected in parallel in pairs and divided into two groups, the left bridge arm and the right bridge arm. The use of IGBTs in parallel can well solve the problem of insufficient IGBT capacity, while ensuring the consistency of impedance. Four groups of IGBTs form a full-bridge inverter circuit, which are turned on in turn, that is, at time t1, the T1 and T3 tubes of the IGBTs in the upper left bridge arm are turned on, and the T6 and T8 tubes of the lower right bridge arm are turned on, and the forward voltage is output. At time t2, the T2 and T4 tubes of the lower left bridge arm are turned on, and the T5 and T7 tubes of the upper right bridge arm are turned on, and the reverse voltage is output, and the alternating current is output in a cycle.

[0056] The working principle of the inverter circuit of this embodiment is as follows: the parameters input by the welding machine are calculated through the PLC, the required voltage value is converted into a digital quantity, and then the DA module is used for output, and the calculated digital quantity is converted into 4-20mA and input into the inverter controller. This 4-20mA signal is converted into a pulse PWM wave of a certain frequency, and the PWM pulse signal is used to control the on and off of the four groups of IGBTs to control the effective value of the inverter output voltage.

[0057] The three-phase rectifier circuit includes: a first diode D1, a second diode D3, a third diode D5, a first thyristor D2, a second thyristor D4, and a third thyristor D6; the anode of the first diode D1 and the cathode of the first thyristor D2 are connected to the A-phase output end of the power input circuit 110, the anode of the second diode D3 and the cathode of the second thyristor D4 are connected to the B-phase output end of the power input circuit 110, and the anode of the third diode D5 and the cathode of the third thyristor D6 are connected to the C-phase output end of the power input circuit 110; the cathode of the first diode D1, the cathode of the second diode D3, and the cathode of the third diode D5 are respectively connected to the positive input end of the capacitor filter tank circuit, and the anode of the first thyristor D2, the anode of the second thyristor D3, and the anode of the third thyristor D5 are respectively connected to the negative input end of the capacitor filter tank circuit; the control electrode of the first thyristor D2, the control electrode of the second thyristor D4, and the control electrode of the third thyristor D3 are connected to the output end of the control circuit.

[0058] It should be noted that the present embodiment adopts a controlled rectification method, which is controlled by a thyristor. By using a control circuit, when the power supply is just started, the control electrode of the thyristor is controlled by the output of the control circuit, and the conduction angle of the thyristor is slowly increased, which can effectively avoid the impact of large current on the capacitor filter circuit and the generator, and avoid damage to the circuit components.

[0059] Figure 2 FIG. 1 is a circuit diagram of a controllable inverter power supply system provided in this embodiment. Figure 2As shown, in this embodiment, through the communication between PLC and DSP, the required voltage value is converted into a 4-20mA signal through calculation and written into the DSP through conversion. The DSP sends out the corresponding PWM wave signal, and uses the PWM wave to control the on and off of the power switching devices IGBT1~IGBT8 in the inverter circuit.

[0060] In this embodiment, through the communication between SCI and PLC, it is detected whether the PLC has issued a command to start welding. By using eCAP and ePWM, eCAP can capture the phase difference between the drive pulse signal of the IGBT of the left upper bridge arm, namely T1 and T3, and the load current, and ePWM generates four phase-shift control pulse signals to control the opening and closing of the IGBT.

[0061] The driving circuit in this embodiment also includes an optocoupler isolation circuit, a driving buffer circuit and an IGBT driving and protection circuit. The optocoupler isolation circuit is connected to the control circuit and to the driving buffer circuit; the driving buffer circuit is connected to the optocoupler isolation circuit and to the IGBT driving and protection circuit; the IGBT driving and protection circuit is connected to the driving buffer circuit and to the inverter circuit. The optocoupler isolation circuit can electrically isolate the control circuit from the driving circuit, thereby improving the reliability of the operation. The driving buffer circuit can convert the signal emitted by the optocoupler isolation circuit into a 0 / 15V square wave signal to drive and control the IGBT driving module. When the IGBT driving and protection circuit detects an overcurrent or undervoltage fault, the driving module will be used to "soft shut down" the IGBT.

[0062] It should be noted that, in this article, relational terms such as "first" and "second" 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. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0063] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A rail flash welding controlled rectifier inverter power supply system, characterized in that: The invention comprises a power input circuit (110), a three-phase-single-phase controlled rectifier inverter circuit (120), a load circuit (130), a control and drive circuit (140) and a signal setting circuit (150); the power input circuit (110) is connected to the three-phase-single-phase controlled rectifier inverter circuit (120), the three-phase-single-phase controlled rectifier inverter circuit (120) is connected to the load circuit (130) and the control and drive circuit (140), and the control and drive circuit (140) is connected to the signal setting circuit (150).

2. A rail flash welding controlled rectifier inverter power supply system according to claim 1, characterized in that: The power input circuit (110) is connected to a three-phase generator set.

3. A rail flash welding controlled rectifier inverter power supply system according to claim 1, characterized in that: The three-phase-single-phase controllable rectifier inverter circuit (120) comprises a three-phase controllable rectifier circuit, a capacitor filter tank circuit and an inverter circuit, wherein the input end of the three-phase controllable rectifier circuit is connected to the output end of the power input circuit (110), the capacitor filter tank circuit is connected to the output end of the three-phase controllable rectifier circuit, and the inverter circuit input end is connected to the output end of the capacitor filter tank circuit.

4. A rail flash welding controlled rectifier inverter power supply system according to claim 3, characterized in that: The inverter circuit includes: a first IGBT tube T1, a second IGBT tube T2, a third IGBT tube T3, a fourth IGBT tube T4, a fifth IGBT tube T5, a sixth IGBT tube T6, a seventh IGBT tube T7, and an eighth IGBT tube T8; the collector of the first IGBT tube T1, the collector of the third IGBT tube T3, the collector of the fifth IGBT tube T5, and the collector of the seventh IGBT tube T7 are connected to the positive output end of the capacitor filter, the emitter of the second IGBT tube T2, the emitter of the fourth IGBT tube T4, the emitter of the sixth IGBT tube T6, and the emitter of the eighth IGBT tube T8 are connected to the negative output end of the capacitor filter, the gate of the first IGBT tube T1, the gate of the third IGBT tube T3 The gate, the gate of the sixth IGBT tube T6, and the gate of the eighth IGBT tube T8 are connected to the first output end of the inverter drive circuit; the gate of the second IGBT tube T2, the gate of the fourth IGBT tube T4, the gate of the fifth IGBT tube T5, and the gate of the seventh IGBT tube T7 are connected to the second output end of the inverter drive circuit; the emitter of the first IGBT tube T1 and the emitter of the third IGBT tube T3 are connected to the collector of the second IGBT tube T2 and the collector of the fourth IGBT tube T4 to form the first output end of the inverter circuit; the emitter of the fifth IGBT tube T5 and the emitter of the seventh IGBT tube T7 are connected to the collector of the sixth IGBT tube T6 and the collector of the eighth IGBT tube T6 to form the second output end of the inverter circuit.

5. A rail flash welding controlled rectifier inverter power supply system according to claim 3, characterized in that: The three-phase controlled rectifier circuit comprises: a first diode D1, a second diode D3, a third diode D5, a first thyristor D2, a second thyristor D4, and a third thyristor D6; the anode of the first diode D1 and the cathode of the first thyristor D2 are connected to the A-phase output end of the power input circuit (110), the anode of the second diode D3 and the cathode of the second thyristor D4 are connected to the B-phase output end of the power input circuit (110), the anode of the third diode D5 and the cathode of the third thyristor D6 are connected to the The first thyristor D2, the second thyristor D3 and the third thyristor D5 are connected to the C phase output end of the input circuit (110); the cathode D1 of the first diode, the cathode D3 of the second diode and the cathode D5 of the third diode are respectively connected to the positive input end of the capacitor filter tank circuit; the anode D2 of the first thyristor, the anode D3 of the second thyristor and the anode D5 of the third thyristor are respectively connected to the negative input end of the capacitor filter tank circuit; the control electrode of the first thyristor D2, the control electrode of the second thyristor D4 and the control electrode of the third thyristor D3 are connected to the output end of the control circuit.

6. A rail flash welding controlled rectifier inverter power supply system according to claim 1, characterized in that: The load circuit (130) comprises two welding transformers, which are connected in parallel, and the primary sides of the two welding transformers are connected to the output end of the inverter circuit in the three-phase-single-phase controllable rectifier inverter circuit (120), and the secondary sides of the two welding transformers are respectively connected to the moving clamp and the static clamp.

7. A rail flash welding controlled rectifier inverter power supply system according to claim 1, characterized in that: The control and drive circuit (140) is connected to the IGBT of the inverter circuit in the three-phase-single-phase controllable rectifier inverter circuit (120).

8. The rail flash welding controlled rectifier inverter power supply system according to claim 1, characterized in that: The driving and control circuit includes a Hall voltage sensor, a Hall current sensor, a driving circuit, a current zero-crossing detection circuit, a precision rectifier and filter circuit, and a DSP chip; the input end of the Hall voltage sensor is connected to the output end of the capacitor filter rectifier circuit and to the input end of the inverter circuit, the output end of the Hall voltage sensor is connected to the ADC end of the DSP chip, the input end of the driving circuit is connected to the ePWM end of the DSP chip, and the output end of the driving circuit is connected to the IGBT of the inverter circuit; the output end of the inverter circuit is connected to the input end of the Hall current sensor, the output end of the Hall current sensor is connected to the input end of the current zero-crossing detection circuit, and to the input end of the precision rectifier and filter circuit; the output end of the current zero-crossing detection circuit is connected to the eCAP end of the DSP chip, and the ePWM input end of the DSP chip is connected to the eCAP input end of the DSP chip; The output end of the precision rectification and filtering circuit is connected to the ADC end of the DSP chip; the PLC of the signal setting circuit (150) is connected to the SCI end of the DSP chip.

9. A rail flash welding controlled rectifier inverter power supply system according to claim 8, characterized in that: The DSP chip is TMS320F28335.

Images