RU68813U1 - AUTONOMOUS AGREED INVERTER WITH RESONANT COMMUTATION - Google Patents

Abstract

The utility model relates to a conversion technique and can be used in power supplies for induction heaters. The utility model extends the scope of an autonomous matched inverter with resonant switching. The self-contained matched inverter with resonant switching contains two serial circuits connected to the input terminals of the inverter, each consisting of a filter choke 1, 2, a controlled valve 3, 4 with an anti-parallel diode 5, 6 and a second filter choke 7, 8, output the inverter outputs are connected to the common connection points of the controlled valves and the second filter chokes of the corresponding series circuits through switching chokes 9, 10 and are shunted by a compensating capacitor 11, the common connection points are controlled valves and chokes of the filter corresponding series circuits are connected to the common connection points controlled valves and the second throttle filter other serial circuits via capacitors 12, 13. The load 14 is connected to the output terminals of the inverter. 1 ill.

Description

The utility model relates to a conversion technique and can be used in power supplies for induction heaters and other electrotechnological loads. The utility model extends the scope of an autonomous matched inverter with resonant switching.

A self-contained matched inverter with resonant switching is known, comprising a serial circuit connected to the input terminals of the inverter, consisting of a filter choke and a controlled valve with an on-parallel diode, the output terminals of the inverter are connected to common points of connection of the controlled valve and the filter choke through a switching choke and a separation capacitor, and shunted by a compensating capacitor (Electromagnetic processes and parametric synthesis of single-fan inverters with reverse diode m for electrothermies / L.E. Roginskaya, A.V. Ivanov, M.M. Mulmenko and others // Electricity. - 2003. - No. 12. - P. 42).

The disadvantage of a self-contained matched inverter with resonant switching is a narrow scope. This is due to the narrow range of regulation of the output electrical parameters, low reliability due to high voltage levels on the controlled valve and on-parallel diode, which can lead to their failure, the inability to effectively supply remote loads.

Known stand-alone matched inverter with resonant switching, containing two serial circuits connected to the input terminals of the inverter, each consisting of a filter inductor, a controlled valve with an anti-parallel diode and a second inductor, the inverter output terminals are connected to common points

connections of controlled gates and filter chokes and common points of connection of the second chokes of the corresponding series circuits through isolation capacitors (A. S. 1742969 USSR, MKI N05M 7 \ 523. Autonomous resonant inverter \ S.V.Dzliev, E.M. Silkin, S. N. Tazikhin et al. - Declaration 01.10.90, Publ. 23.06.92, B.I. No. 23).

The disadvantage of a self-contained matched inverter with resonant switching is a narrow scope. This is due to the low reliability of operation due to the high voltage levels on the controlled valves and counter-parallel diodes, which can lead to their failure, the inability to use an autonomous matched inverter with resonant switching to power critical consumers requiring high reliability, and the inability to efficiently supply remote loads.

A self-contained matched inverter with resonant switching is known, containing two serial circuits connected to the input terminals of the inverter, each consisting of a filter choke, a switching choke, a controlled valve with an anti-parallel diode and a second filter choke, the output terminals of the inverter are connected to common connection points of the controlled gates and second chokes of the filter of the corresponding series circuits, common points of connection of controlled gates and switching chokes of the corresponding series of circuits are connected to common points of connection of controlled gates and second chokes of the filter of other series circuits through isolation capacitors (AS 1711309 USSR, MKI I05M 7 \ 523. Autonomous inverter \ EM Silkin, SV Dzliev, Yu. P. Kachan et al. - Declaration of 05/18/90, Publ. 07.02.92, B.I. No. 5).

The specified autonomous matched inverter with resonant switching is the closest in technical essence to a utility model and is selected as a prototype.

The disadvantage of an autonomous matched resonant inverter with resonant switching is a narrow field of application. This is due to the low reliability of operation due to the high voltage levels on the controlled valves and counter-parallel diodes, which can lead to their failure, the inability to use an autonomous matched inverter with resonant switching to power critical consumers requiring high reliability, and the inability to efficiently supply remote loads.

The utility model is aimed at solving the problem of expanding the field of application of an autonomous matched inverter with resonant switching, which is the purpose of the utility model.

This goal is achieved by the fact that the self-contained matched inverter with resonant switching contains two serial circuits connected to the input terminals of the inverter, each consisting of a filter choke, a controlled valve with an anti-parallel diode and a second filter choke, the output terminals of the inverter are connected to common connection points controlled valves and second filter chokes of the corresponding series circuits through switching chokes and are shunted by a compensating capacitor, common points the lengths of the controlled gates and filter chokes of the corresponding series circuits are connected to the common points of the connection of the controlled valves and the second filter chokes of the other series circuits through isolation capacitors.

A significant difference characterizing the utility model is the expansion of the scope of application of a self-contained matched inverter with resonant switching, which is achieved by increasing the reliability of operation by providing a reduction in voltage levels on controlled valves and counter-parallel diodes, which reduces the likelihood of failure, and the ability to use a self-contained matched

resonant switching inverter for supplying critical consumers requiring high reliability with the ability to efficiently power remote loads.

The expansion of the scope of an autonomous matched inverter with resonant switching is the obtained technical result due to new elements in the circuit of an autonomous matched inverter, the order of their inclusion and new connections, that is, the hallmarks of the utility model. Thus, the distinguishing features of the claimed autonomous matched inverter with resonant switching are essential.

The figure shows a diagram of an autonomous matched inverter with resonant switching.

The self-contained matched resonant inverter contains two serial circuits connected to the input terminals of the inverter, each consisting of a filter choke 1, 2, a controlled valve 3, 4 with an anti-parallel diode 5, 6, and a second filter choke 7, 8, and the inverter output connected to common points of connection of controlled gates and second chokes of the filter of the corresponding series circuits through switching chokes 9, 10 and shunted by a compensating capacitor 11, common points of connection of controlled gates, etc. filter axles of the corresponding series circuits are connected to common points of connection of the controlled valves and second filter chokes of the other series circuits through isolation capacitors 12, 13. The load 14 is connected to the output terminals of the inverter.

Autonomous matched inverter with resonant switching in steady state operates as follows. The control pulses to the controlled valves 3, 4 are applied alternately at the moments when the voltage across the compensating capacitor 11 passes through zero to the positive and negative range of values (+ on the left or right compensating capacitor plate lining 11), respectively. Options

switching chokes 9, 10, capacitances of the compensating capacitor 11 and isolation capacitors 12, 13 are selected from the condition for ensuring the oscillatory nature of the current in the circuits: 12 - 3 - 9 - (11, 14) - 10 - 12 and 13 - 4 - 10 - (11 , 14) - 9 - 13, formed when the controlled valves 3 and 4 are turned on. The natural frequency of the circuits is approximately 4 times higher than the output frequency of the device. The inductances of the filter chokes 1, 2, 7, 8 are selected sufficient for high-quality filtering of current and voltage at the inputs of serial circuits containing switching chokes 9, 10, a parallel circuit formed by a compensating capacitor 11 and output terminals with an connected inductor 14, and isolation capacitors 12 , 13. Compensating capacitor 11 provides parallel compensation of the reactive power of the induction heater (inductor or load) 14 and sequential compensation, together with a separator capacitors 12, 13 (at the final value of their capacitance), reactive power of switching reactors 9, 10. Switching reactors 9, 10 can be implemented as independent elements or represent load inductances (part of the load) and (or) connecting discharge busbars (cables ) autonomous matched inverter. A positive half-period of the output alternating voltage is formed during operation of the controlled valve 3 and anti-parallel diode 5, and a negative half-period during the operation of the controlled valve 4 and anti-parallel diode 6. The controlled valves 3 and 4 at maximum output alternating voltage (maximum output power) are switched on phase shift 180 degrees. email (alternately). The regulation of the output electrical parameters of a self-contained matched inverter is carried out by adjusting the phase from 180 to 0 degrees. email In operation mode with a phase angle of 0 degrees. email (simultaneous activation of controlled valves 3, 4) the output power of a self-contained matched inverter is zero, since the discharge currents of the separation capacitors 12, 13 are subtracted.

The total current through the parallel load circuit (11, 14) with a phase shift of 0 deg. email equal to zero. In maximum output power mode, the full cycle (period) of the output signal of an autonomous matched inverter with resonant switching consists of six time intervals corresponding to various combinations of on and off state of controlled valves 3, 4 and counter-parallel diodes 5, 6. Electromagnetic processes at each half-cycle in the circuit flow similarly except that different controlled gates 3 or 4 and counter-parallel diodes 5 or 6 are involved in the operation. As controlled gates st can be used as single-operation or dual-operation valves without reverse or reverse conductivity (with anti-parallel diode). Moreover, the electromagnetic processes in the circuit are qualitatively similar. Consider an embodiment of a circuit based on a controlled two-operation valve (transistor) with an anti-parallel diode. The main (first or fourth) interval corresponds to the direct conduction interval of controlled valve 3 (or controlled valve 4). When the controlled valve 3 is turned on, an oscillatory charge begins with the positive polarity of the compensating capacitor 11 along the circuit: 12 - 3 - 9 - (11, 14) - 10 - 12 from the Separating capacitor 12 and the power supply of an autonomous matched inverter. At the same time, the compensating capacitor 11 is discharged through the inductor 14 in the circuit: 11 -14 - 11. After the oscillatory current drop in the circuit: 12 - 3 - 9 - (11, 14) - 10 - 12 to zero, the compensating capacitor 11 is charged to the maximum positive voltage , which exceeds the voltage at the isolation capacitor 12. The discharge (second interval) of the compensating capacitor 11 begins along the circuit: (11, 14) - 9 - 6 - 12 - 10 - (11, 14). A reverse current flows through an anti-parallel diode 6 of the controlled valve 3. In the second interval, the control pulse is removed from the controlled valve 3. At the same time, the compensating capacitor 11 is also discharged through the inductor 14 in the circuit: 11 - 14 - 11. After the oscillatory current drop in the circuit: (11,

14) - 9 - 6 - 12 - 10 - (11, 14) to zero the counter-parallel diode 6 of the controlled valve 3 is turned off. At the same time, the voltage at the compensating capacitor 11 remains positive and its value is less than the voltage at the isolation capacitor 12. At the third time interval, the compensating capacitor 11 continues to recharge in the circuit: 11 - 14 - 11 to a voltage of negative polarity (+ on the right-hand side wiring diagram) due to the energy stored in the electromagnetic fields of the compensating capacitor 11 and the inductor 14. At the maximum negative voltage on the compensating capacitor 11 on the controlled valve 3 are present The maximum positive voltage equal to the sum of the voltages at the isolation capacitor 112 and the compensating capacitor 12 (approximately twice the supply voltage) is generated. The third interval in the operation of the self-contained matched inverter ends when the compensating capacitor 11 is completely discharged. The difference between the currents of the filter chokes 1, 7 and 2, 8 flows through the load circuit 11.14. At the time of the transition of voltage across the compensating capacitor 11 (or earlier when working with the lead angle ) through zero in the negative region turns on the controlled valve 4 (fourth interval). Electromagnetic processes are qualitatively repeated, but the currents and voltages on the elements 9, (11, 14), 10 have the opposite sign. At the time of the transition of the voltage across the compensating capacitor 11 through zero to the positive range of values, the period ends in the operation of the autonomous matched inverter, the next control pulse is applied, the controlled valve 3 is turned on, and the next period in the operation of the autonomous matched inverter starts. When using dual-operation controlled valves 3, 4, it is advisable to set the second interval of short duration by choosing the parameters of the circuit elements, which ensures higher energy performance of the device. In the conduction interval of counter-parallel diodes 5, 6, a small reverse (negative) voltage equal to the voltage drop across

counter-parallel diode 5 or 6, respectively, and controlled valves can restore their control properties (when using single-operation valves). In this case, the duration of the second interval is set based on the required shutdown time of the used single-operation controlled valves 3, 4.

Controlled valves 3, 4 when implementing an autonomous matched inverter with resonant switching, as described above, can be performed as single-operation symmetrical or without reverse blocking ability (thyristors of various types, reversibly-switched dynistors, gas-discharge valves), and two-operation, i.e. fully controlled by symmetric or unbalanced (lockable thyristors, transistors of various types, combination keys).

Compared with the prototype, the scope of application of an autonomous matched inverter with resonant switching is significantly expanded. This is achieved by increasing reliability and energy performance by reducing currents and voltages at controlled valves and counter-parallel diodes (by more than two times), overvoltage levels at controlled valves that occur when they are turned off, and electromagnetic interference levels that occur when controlled valves are turned off and counter-parallel diodes, non-rigid switching of controlled gates, the ability to supply responsible consumers and / or remote loads from an autonomous coordinated inverter and. The stability of the autonomous coordinated inverter with resonant switching is increased and the likelihood of inversion failures (execution on single-operation controlled valves) when working on a widely varying electrotechnological load (induction heater), as well as failures in the inverter control system, is reduced.

Additionally (in comparison with the prototype), the design of the energy (power) part of the inverter can be significantly simplified and the scope of application can be expanded by providing the possibility of using controlled valves and counter-parallel

diodes with reduced requirements for their parameters and lower price.

Compared with the prototype, the efficiency of an autonomous matched inverter with resonant switching is further increased by reducing currents and switching energy losses in controlled gates and counter-parallel diodes (lowering levels of switching overvoltage, initial rise and fall rates of currents when turning on and off controlled valves and counter-parallel diodes, recovery of part of the energy of the overvoltage in the load).

Claims (1)

A self-contained matched inverter with resonant switching, containing two serial circuits connected to the input terminals of the inverter, each consisting of a filter choke, a controlled valve with an anti-parallel diode and a second filter choke, the output terminals of the inverter are connected to common points of connection of the controlled valves and second chokes filter corresponding serial circuits through switching chokes and are shunted by a compensating capacitor, common points of connection of controlled valves and osseley filter respective series circuits are connected to the common connection points controlled valves and the second throttle filter other serial circuits via capacitors.