CN201639482U - High-voltage isolated multi-output IGCT drive power supply - Google Patents

Abstract

The utility model proposes a new high-voltage isolation multi-output IGCT drive power supply, including a power frequency input diode rectifier bridge, a filter capacitor C1, an inverter bridge, a DC blocking capacitor C6, an additional inductor L1, a transformer CT, and several output high isolation voltages Transformer (Tr1~Trn), several secondary diode rectifier bridges, several chopper voltage regulator circuits, several closed-loop control PWM generation isolation drive circuits, transformer CT output terminal diode rectifier bridge, filter LC, closed-loop control, PWM generation isolation and Drive circuit. The current closed-loop control is adopted in the primary side circuit, and the chopper voltage regulation closed-loop control is set in each secondary side output circuit, which can output a stable isolated output voltage that meets the IGCT drive requirements.

Description

High-voltage isolated multi-output IGCT drive power supply

technical field

The utility model relates to a high-voltage isolation device driven by a large-capacity power electronic device IGCT (or GCT) specially used in a medium-high voltage large-capacity power electronic device (such as a multi-level power inverter and a bridge-type short-circuit fault current limiter). Multiple output power supplies. It is mainly used in industrial fields such as flexible AC transmission system, large-capacity wind power grid-connected, large-capacity medium and high-voltage photovoltaic power grid-connected inverter, and large-capacity water pump fan speed regulation. It is a high-voltage, multi-output isolated power supply system driven by IGCTs in large-capacity medium- and high-voltage power electronic equipment.

Background technique

With the rapid development of the power industry, medium and high voltage power electronic equipment based on large-capacity IGCTs, such as multi-level power inverters, bridge-type short-circuit fault current limiters, large-capacity reactive power compensation, large-capacity wind power grid-connected, large Medium and high-voltage photovoltaic power generation grid-connected inverters, large-capacity water pump fan speed control systems, etc. are more and more widely used. In these IGCT-based large-capacity power electronic equipment, the number of power electronic switching devices IGCT is increasing, and the requirements for IGCT driving power technology are also getting higher and higher. In order to complete the turn-on and turn-off of the controllable switch safely, reliably, quickly and accurately, there are strict requirements on the power supply of the drive circuit: 1) Isolation and withstand voltage requirements. Since the positions of the controllable switches in the main circuit are different, the potentials are different, and the potential difference between different tubes is very large. Therefore, in order to ensure the safe and reliable operation of the tubes, it is objectively required that both the control circuit and the switch tube be connected. Between the control poles and between the control poles of different switch tubes, they must be isolated from each other, and there must be a sufficiently high isolation voltage. It is specifically manifested in the driving power supply, that is, the outputs of each group of the driving power supply are isolated from each other, and there must be sufficient withstand voltage. 2) There must be enough mutually isolated outputs. For example, a three-level inverter requires 12 isolated power supplies. For inverters with more levels, the number of IGCTs and the number of isolated driving power supplies are greater. 3) Power requirements. To reliably and quickly complete the turn-on and turn-off operations of high-power switching tubes, the driving power supply must have sufficient power output capability, and the driving power required for large-capacity IGCTs is generally above 60W. 4) Sufficient and stable voltage amplitude. The gate turn-on voltage of the tube often has a threshold value, and the tube can be turned on only when the driving voltage is greater than the threshold value. For the sake of reliability, there should be a margin for the voltage amplitude, but too high gate voltage will damage the gate. At the same time, in order to prevent the closed tube from being mis-conducted due to interference signals and quickly turn off the tube in the on-state, the drive power supply A negative voltage of a certain magnitude is required, so the voltage magnitude can neither be too low nor exceed the safe range of the gate. 5) Each output of the isolated power supply must have sufficient load regulation. The drive power required for the off-state, on-state and switching process of the tube is very different, which is equivalent to the high-speed change of the power supply load in a wide range, and the power supply voltage is required to be stable under various load conditions. 6) Lead requirements. Since there are many power devices in medium and high voltage power converters, especially high voltage power converters and they are in a high voltage environment, it is first necessary to ensure that the connecting wires are safe and reliable, meet the insulation or isolation requirements of the high voltage system, and at the same time be convenient and easy to operate. Judging from prior art documents and industrial sites, existing IGCT drive power supplies generally have disadvantages such as large volume, high cost, inconvenient installation, and low efficiency.

Utility model content

The purpose of the utility model is to overcome the defects of the prior art, and propose a high-voltage isolation multi-output IGCT drive power supply with more optimized structure, smaller volume, lower cost, higher efficiency and reliability.

The utility model has a high-voltage isolation multi-output IGCT drive power supply, including a power frequency input diode rectifier bridge, a filter capacitor C1, an inverter bridge, a DC blocking capacitor C6, an additional inductance L1, a transformer CT, and several output high isolation voltage transformers (Tr1~Trn ), a number of secondary side diode rectifier bridges, a number of chopper voltage regulator circuits, a number of closed-loop control PWM generation isolation drive circuits, a diode rectifier bridge at the output end of the transformer CT, a filter LC, closed-loop control, and PWM generation isolation and drive circuits. The output terminal of the power frequency input diode rectifier bridge is connected to the filter capacitor C1. The positive pole on the DC side of the inverter bridge is connected to the positive pole on the DC side of the power frequency input diode rectifier bridge, and the negative pole on the DC side of the inverter bridge is connected to the negative pole on the DC side of the power frequency input diode rectifier bridge. Each output high isolation voltage transformer (Tr1-Trn) is connected in series with the primary side of the transformer CT, and then connected in series with the DC blocking capacitor C6 and the additional inductance L1, and connected to the AC output end of the inverter bridge. The output of the transformer CT is connected to the AC input terminal of the diode rectifier bridge at the output end of the transformer CT, and the DC output of the diode rectifier bridge at the output end of the transformer CT is connected to the filter LC, and the output of the filter is divided by the voltage dividing resistors (R1, R2) , sent to the isolation and drive circuit generated by the closed-loop control PWM. The four isolated outputs of the closed-loop control PWM generation isolation and drive circuit are respectively connected to the gate and source of the four power MOSFETs in the inverter bridge. The secondary side of the output high isolation voltage transformer (Tr1-Trn) is connected to the AC input terminal of the corresponding secondary diode rectifier bridge and the parallel chopper voltage stabilizing circuit of each secondary diode rectifier bridge. The gate of the MOSFET tube in the chopper voltage regulator circuit is controlled by the closed-loop control PWM generated by the output voltage in the secondary side circuit to generate an isolated drive circuit.

The chopper voltage stabilizing circuit is composed of a smoothing inductor, a chopping MOSFET tube, a reverse discharge prevention diode and a flat capacitor, wherein the first end of the smoothing inductor is connected to the positive pole of the secondary diode rectifier bridge, and the second end is connected to the chopper. The drain of the MOSFET tube and the anode of the reverse discharge prevention diode are connected together; the cathode of the reverse discharge prevention diode and the positive pole of the smoothing capacitor are connected together; the source of the chopping MOSFET, the negative pole of the smoothing capacitor and the secondary diode The negative poles of the rectifier bridges are connected together.

The utility model's high-voltage isolation multi-output IGCT drive power supply can achieve relatively large power and high load adjustment rate, and can fully meet the requirements of the IGCT drive circuit. A set of power supply system can be used for all medium and high voltage power electronic devices. IGCT provides driving power. It has significant advantages such as small size, light weight, convenient installation, good performance and high efficiency.

Description of drawings

Fig. 1 is a schematic diagram of a high-voltage isolated multi-output IGCT driving power supply circuit of the present invention.

Detailed ways

As shown in Figure 1, the high-voltage isolated multi-output IGCT drive power supply includes power frequency input diode rectifier bridge, filter capacitor C1, inverter bridge, DC blocking capacitor C6, additional inductor L1, transformer CT, and several output high isolation voltage transformers ( Tr1～Trn), several secondary diode rectifier bridges, several chopper voltage regulator circuits, several closed-loop control PWM generation isolation drive circuits, transformer CT output diode rectifier bridge, filter LC, closed-loop control, PWM generation isolation and drive circuit . The output terminal of the power frequency input diode rectifier bridge is connected to the filter capacitor C1. The inverter bridge is composed of four power MOSFETs (Q1~Q4) and buffer capacitors C2-C5. C2, C3, C4, and C5 are respectively connected in parallel between the drains and sources of Q1, Q2, Q3, and Q4. The drains of Q1 and Q3 are connected together, which is the positive pole of the DC side of the inverter; the sources of Q2 and Q4 are connected together, which is the negative pole of the DC side of the inverter; the source of Q1 and the drain of Q2 are connected together , is an AC output terminal of the inverter; the source of Q3 and the drain of Q4 are connected together, which is the other AC output terminal of the inverter. The positive pole on the DC side of the inverter bridge is connected to the positive pole on the DC side of the power frequency input diode rectifier bridge, and the negative pole on the DC side of the inverter bridge is connected to the negative pole on the DC side of the power frequency input diode rectifier bridge. Each output high isolation voltage transformer (Tr1~Trn) is connected in series with the primary side of a transformer CT for current detection, and then connected in series with DC blocking capacitor C6 and additional inductance L1, and connected to the AC output end of the inverter bridge. The additional inductance L1 is used to meet the conditions for realizing soft switching. The output of the transformer CT is connected to the AC input terminal of the diode rectifier bridge at the output end of the transformer CT composed of diodes D5-D8, and the DC output of the diode rectifier bridge at the output end of the transformer CT is connected to the filter LC composed of the inductor L2 and the capacitor C7. After the voltage divider output is divided by the voltage divider resistors R1 and R2, it is sent to the isolation and drive circuit (primary side inverter control circuit) generated by the closed-loop control PWM. The closed-loop control and PWM generation isolation and the four isolated outputs of the drive circuit are respectively connected to the gates and sources of the four power MOSFETs in the inverter bridge. The secondary side of the output high isolation voltage transformer (Tr1-Trn) is connected to the AC input terminal of the corresponding secondary diode rectifier bridge and the parallel chopper voltage stabilizing circuit of each secondary diode rectifier bridge. The gate of the MOSFET tube in the chopper voltage regulator circuit is controlled by the closed-loop control PWM generated by the output voltage in the secondary side circuit to generate an isolated drive circuit. The secondary side circuit of Tr2-Trn in the figure is exactly the same as that of Tr1. The output high isolation voltage transformer (Tr1～Trn) is a high-frequency transformer. In order to improve the isolation voltage, high-voltage cables can be used for both the primary side and the secondary side. single turn. The chopper voltage regulator circuit is composed of inductor L3, MOSFET tube Q5 and diode D13. Since the main circuit on the primary side adopts current closed-loop control, the secondary side of the transformer is approximately a current source, so Q5 is actually a BUCK circuit of a current source, not a BOOST circuit in its form. D13 is used to prevent the output filter capacitor from short-circuiting discharge through Q5. The gate of Q5 is controlled by the closed-loop control PWM generated by the output voltage in the secondary circuit to generate an isolated drive circuit. The PWM generation circuit can be composed of TL494, UC3524, UC3525, UC3825 and other integrated circuits and their peripheral resistance-capacitance components. Since the secondary side of the power supply adopts closed-loop control composed of dedicated PWM integrated circuits TL494, UC3524, UC3525, UC3825, etc., it can achieve relatively large power and high load regulation rate, and can fully meet the requirements of the IGCT drive circuit. The power system can provide driving power for all IGCTs in medium and high voltage power electronic devices.

After the system is powered on, the 220V AC power is converted into DC by the power frequency input diode rectifier bridge, filtered by the smoothing capacitor C1, and supplies power to the inverter composed of Q1-Q4. The high-frequency AC current output by the inverter is added to the primary side of several output transformers in series, and a proportional high-frequency current is generated on the secondary side of the output transformer, which is rectified into DC by the secondary diode rectifier bridge, and then passed through the secondary After adjustment, the chopper voltage regulator circuit is added between the gate and source of the IGCT to provide isolated driving power for the IGCT. High-frequency AC current is added to the primary side of the transformer CT at the same time, and a proportional AC current is generated on the secondary side of the transformer CT. After being rectified by the diode rectifier bridge at the output end of the CT, LC filtered, and resistor divided, it is used for current detection and The feedback signal acts on the closed-loop control of the inverter bridge and the PWM generation isolation and drive circuit to control the high-frequency AC current output by the inverter to stabilize at the set value. Since the current closed-loop control of the main circuit can only stabilize the high-frequency AC current of the inverter, it cannot stabilize the output voltage of each channel. set value. Secondary side closed-loop control and PWM generation isolation and drive circuit, according to the output voltage setting value and feedback voltage value, perform closed-loop adjustment, generate a PWM signal with a suitable duty ratio, control the MOSFET tube in the chopper circuit, and generate stable output voltage.

Claims (2)

1. a high pressure is isolated many output IGCT driving powers, comprises that (Tr1～Trn), some secondary diode rectifier bridges, some chopper stabilivolt circuit, some closed-loop control PWM generate isolated drive circuit, instrument transformer output diode rectifier bridge, filter LC, closed-loop control PWM and generate and isolate and drive circuit for power frequency input diode rectifier bridge, filter capacitor (C1), inverter bridge, capacitance (C6), additional inductor (L1), instrument transformer (CT), some output high-isolating transformers; It is characterized in that: power frequency input diode rectification bridge output end connects filter capacitor (C1); The positive pole of inverter bridge DC side connects the positive pole of power frequency input diode rectifier bridge DC side, and the negative pole of inverter bridge DC side connects the negative pole of power frequency input diode rectifier bridge DC side; Each is exported the high-isolating transformer and (after the Tr1～Trn) and the former limit of instrument transformer (CT) be connected in series, connects with capacitance (C6), additional inductor (L1) again, be connected on the ac output end of inverter bridge; The output of instrument transformer (CT) connects the ac input end of instrument transformer output diode rectifier bridge, the direct current output of instrument transformer output diode rectifier bridge connects filter (LC), filter (LC) output is sent by closed-loop control PWM and is generated isolation and drive circuit after divider resistance (R1, R2) dividing potential drop; Closed-loop control PWM generates and isolates grid and the source electrode that is connected four power MOSFET tubes in the inverter bridge with four tunnel outputs of isolating of drive circuit respectively; Output high-isolating transformer (AC input terminal of the secondary diode rectifier bridge of the secondary side joint correspondence of Tr1～Trn), the parallel connection chopping voltage stabilizing circuit of each secondary diode rectifier bridge; The grid of the MOSFET pipe in the chopper stabilivolt circuit generates isolated drive circuit control by closed-loop control PWM.

2. a kind of high pressure according to claim 1 is isolated many output IGCT driving powers, it is characterized in that: described chopper stabilivolt circuit is made up of flat ripple inductance, copped wave MOSFET pipe, prevention back discharge diode peace ripple electric capacity, the positive pole of the first termination secondary diode rectifier bridge of wherein flat ripple inductance, the anode of the drain electrode of second end and copped wave MOSFET pipe, prevention back discharge diode is connected together; Stop the negative electrode of back discharge diode and the positive pole of flat wave capacitor to be connected together; The negative pole of the source electrode of copped wave MOSFET pipe, the negative pole of flat wave capacitor and secondary diode rectifier bridge is connected together.

Images