24 pulse wave rectifier frequency convertor systems
Technical field
The present invention relates to a kind of frequency convertor system, particularly a kind of frequency convertor system reduced input electrical network generation harmonic effects.
Background technology
The frequency converter adopted in electric motor drive system or part generate electricity system is generally two quadrant frequency converter, two quadrant frequency converter is larger on the impact of electrical network output harmonic wave, in order to overcome this shortcoming, employing 6 pulse wave or 12 pulse wave rectifier modes are had in prior art, for two quadrant inversion side provides high-quality direct voltage, for realizing the mode of 12 impulse commutations, generally introduce phase shifting transformer in systems in which, make each input voltage of rectification unit in parallel realize phase shift, cancel out each other and the raising of rectification output dc voltage quality to realize grid side harmonic wave.But there is the unbalanced problem of each road output voltage in phase shifting transformer, and each commutating circuit impedance can not be completely the same, cause rectification unit input current in parallel unbalanced, make grid side harmonic wave cancel out each other and rectification output dc voltage quality improve effect can not produce a desired effect, in order to overcome this shortcoming, also have and adopt other multiple-pulse rectifier systems, but there is the defect controlling complicated and cost intensive.
Summary of the invention
The invention provides a kind of 24 pulse wave rectifier frequency convertor systems and euqalizing current control method thereof, solve with the frequency convertor system of the phase shifting transformer technical problem large to grid side harmonic effects.
The present invention solves above technical problem by the following technical programs:
The total design of the present invention is the balance being reached each rectification module input current by the inductance value of the input reactance device on each output loop of adjustment phase shifting transformer, thus reduces the harmonic effects to electrical network; And make rectification module outputting high quality direct voltage by the mode arranging 24 pulse wave rectifiers at phase shifting transformer output, make phase shifting transformer input side each road harmonic wave cancel out each other, harmonic reduction is on the impact of electrical network simultaneously.
A kind of 24 pulse wave rectifier frequency convertor systems, comprise electrical network, phase shifting transformer, input reactance device, rectification module, inversion module and load, the three-phase output voltage of electrical network and the former limit input of phase shifting transformer link together, the output of inversion module is connected with load, the first via of phase shifting transformer exports and is connected with first via input reactance device, first via input reactance device and the first rectification module link together, second tunnel of phase shifting transformer exports and is connected with the second tunnel input reactance device, second tunnel input reactance device and the second rectification module link together, 3rd tunnel of phase shifting transformer exports and is connected with the 3rd tunnel input reactance device, 3rd tunnel input reactance device and the 3rd rectification module link together, 4th tunnel of phase shifting transformer exports and is connected with the 4th tunnel input reactance device, 4th tunnel input reactance device and the 4th rectification module link together, the direct current output plus terminal of the first rectification module, the direct current output plus terminal of the second rectification module, input anode with the direct current of inversion module after the direct current output plus terminal of the 3rd rectification module and the direct current output plus terminal of the 4th rectification module are connected in parallel to link together, the direct current of the first rectification module exports negative terminal, the direct current of the second rectification module exports negative terminal, input negative terminal with the direct current of inversion module after the direct current output negative terminal of the 3rd rectification module and the direct current output negative terminal of the 4th rectification module are connected in parallel to link together, input between negative terminal at the direct current input anode of inversion module and the direct current of inversion module and be parallel with DC support electric capacity.
First via input reactance device, the second tunnel input reactance device, the 3rd tunnel input reactance device are the reactors that inductance value is identical with the 4th tunnel input reactance device, and the first rectification module, the second rectification module, the 3rd rectification module and the 4th rectification module are identical diode rectification modules.
An euqalizing current control method for 24 pulse wave rectifier frequency convertor systems, comprises the following steps:
The first step, the former limit input of the three-phase output voltage of electrical network and phase shifting transformer is linked together, the output of inversion module connects load, the first via of phase shifting transformer exports upper connection first via input reactance device, first via input reactance device and the first rectification module link together, second tunnel of phase shifting transformer exports upper connection second tunnel input reactance device, second tunnel input reactance device and the second rectification module link together, 3rd tunnel of phase shifting transformer exports upper connection the 3rd tunnel input reactance device, 3rd tunnel input reactance device and the 3rd rectification module link together, 4th tunnel of phase shifting transformer exports upper connection the 4th tunnel input reactance device, 4th tunnel input reactance device and the 4th rectification module link together, the direct current output plus terminal of the first rectification module, the direct current output plus terminal of the second rectification module, input anode with the direct current of inversion module after the direct current output plus terminal of the 3rd rectification module and the direct current output plus terminal of the 4th rectification module are connected in parallel to link together, the direct current of the first rectification module exports negative terminal, the direct current of the second rectification module exports negative terminal, input negative terminal with the direct current of inversion module after the direct current output negative terminal of the 3rd rectification module and the direct current output negative terminal of the 4th rectification module are connected in parallel to link together, input between negative terminal at the direct current input anode of inversion module and the direct current of inversion module and be parallel with DC support electric capacity,
The input current of second step, the input current of simultaneously monitoring first via input reactance device, the input current of the second tunnel input reactance device, the input current of the 3rd tunnel input reactance device and the 4th tunnel input reactance device;
3rd step, compare four current values monitored in second step, according to the inductance value of the inductance value of current value adjustment first via input reactance device, the inductance value of the second tunnel input reactance device, the inductance value of the 3rd tunnel input reactance device and the 4th tunnel input reactance device, until the four road current values monitored are identical.
The present invention adopts 24 pulse wave rectifier unit and by the adjustment of input reactance device inductance value, reaches the equilibrium of frequency convertor system each road rectification input current, obviously improve frequency convertor system combination property.Solve the local overheating problem that frequency converter long-play under unbalanced current condition brings, ensure frequency converter operation stability, extend the useful life of frequency converter.By regulating current-unbalance degree, effectively inhibit the harmonic content in phase shifting transformer input current, reducing the pollution of harmonic current to electrical network.
Accompanying drawing explanation
Fig. 1 is electrical block diagram of the present invention.
Embodiment
Below in conjunction with accompanying drawing, the present invention is described in detail:
A kind of 24 pulse wave rectifier frequency convertor systems, comprise electrical network 1, phase shifting transformer 2, input reactance device, rectification module, inversion module 5 and load 6, the three-phase output voltage of electrical network 1 and the former limit input of phase shifting transformer 2 link together, the output of inversion module 5 is connected with load 6, the first via of phase shifting transformer 2 exports and is connected with first via input reactance device 3, first via input reactance device 3 and the first rectification module 4 link together, second tunnel of phase shifting transformer 2 exports and is connected with the second tunnel input reactance device 7, second tunnel input reactance device 7 and the second rectification module 8 link together, 3rd tunnel of phase shifting transformer 2 exports and is connected with the 3rd tunnel input reactance device 9, 3rd tunnel input reactance device 9 and the 3rd rectification module 10 link together, 4th tunnel of phase shifting transformer 2 exports and is connected with the 4th tunnel input reactance device 11, 4th tunnel input reactance device 11 and the 4th rectification module 12 link together, the direct current output plus terminal of the first rectification module 4, the direct current output plus terminal of the second rectification module 8, input anode with the direct current of inversion module 5 after the direct current output plus terminal of the 3rd rectification module 10 and the direct current output plus terminal of the 4th rectification module 12 are connected in parallel to link together, the direct current of the first rectification module 4 exports negative terminal, the direct current of the second rectification module 8 exports negative terminal, input negative terminal with the direct current of inversion module 5 after the direct current output negative terminal of the 3rd rectification module 10 and the direct current output negative terminal of the 4th rectification module 12 are connected in parallel to link together, input between negative terminal at the direct current input anode of inversion module 5 and the direct current of inversion module 5 and be parallel with DC support electric capacity 13.
First via input reactance device 3, second tunnel input reactance device the 7, the 3rd tunnel input reactance device 9 is reactors that inductance value is identical with the 4th tunnel input reactance device 11, and the first rectification module 4, second rectification module 8, the 3rd rectification module 10 and the 4th rectification module 12 are identical diode rectification modules.
An euqalizing current control method for 24 pulse wave rectifier frequency convertor systems, comprises the following steps:
The first step, the former limit input of the three-phase output voltage of electrical network 1 and phase shifting transformer 2 is linked together, the output of inversion module 5 connects load 6, the first via of phase shifting transformer 2 exports upper connection first via input reactance device 3, first via input reactance device 3 and the first rectification module 4 link together, second tunnel of phase shifting transformer 2 exports upper connection second tunnel input reactance device 7, second tunnel input reactance device 7 and the second rectification module 8 link together, 3rd tunnel of phase shifting transformer 2 exports upper connection the 3rd tunnel input reactance device 9, 3rd tunnel input reactance device 9 and the 3rd rectification module 10 link together, 4th tunnel of phase shifting transformer 2 exports upper connection the 4th tunnel input reactance device 11, 4th tunnel input reactance device 11 and the 4th rectification module 12 link together, the direct current output plus terminal of the first rectification module 4, the direct current output plus terminal of the second rectification module 8, input anode with the direct current of inversion module 5 after the direct current output plus terminal of the 3rd rectification module 10 and the direct current output plus terminal of the 4th rectification module 12 are connected in parallel to link together, the direct current of the first rectification module 4 exports negative terminal, the direct current of the second rectification module 8 exports negative terminal, input negative terminal with the direct current of inversion module 5 after the direct current output negative terminal of the 3rd rectification module 10 and the direct current output negative terminal of the 4th rectification module 12 are connected in parallel to link together, input between negative terminal at the direct current input anode of inversion module 5 and the direct current of inversion module 5 and be parallel with DC support electric capacity 13,
The input current of second step, the input current of simultaneously monitoring first via input reactance device 3, the input current of the second tunnel input reactance device 7, the input current of the 3rd tunnel input reactance device 9 and the 4th tunnel input reactance device 11;
3rd step, compare four current values monitored in second step, according to the inductance value of the inductance value of current value adjustment first via input reactance device 3, the inductance value of the second tunnel input reactance device 7, the inductance value of the 3rd tunnel input reactance device 9 and the 4th tunnel input reactance device 11, until the four road current values monitored are identical.
24 pulse wave rectifier frequency convertor systems via phase shifting transformer 2 from electrical network 1 or generating set power taking, four output circuits of phase shifting transformer 2 for being connected in parallel, according to formula I=U/Z,
When four road commutating circuit middle impedances are identical, phase shifting transformer can export four road equalizing voltages in theory, identical input reactance device is configured respectively at rectification unit input side, all voltage can be met, current harmonics requirement, but in fact phase shifting transformer in use cannot realize output four road equalizing voltage, because output voltage is different, cause rectification module input current different, it is identical that the present invention adjusts four tunnel input reactance devices inductance value by monitoring four road rectification module input currents reaches four road rectification module input current value, what rectification circuit was produced significantly reduces the harmonic effects of grid side.
For the two quadrant frequency convertor system using diode as rectification module, can be used as generator telegram in reply and utilize system and drive motor variable frequency power supply.No matter frequency converter utilizes system or variable frequency power supply as telegram in reply, all must meet electric power system for requirements such as capacity, voltage, current harmonic content, applied environments.6 pulse wave rectifier unit are adopted for common two quadrant frequency convertor system, for reducing voltage, current harmonics to the pollution of electrical network, meet voltage, current harmonics (THD) requirement, need at transformer outlet side, i.e. rectification module input side configuration reactor, reactor plays the effect of filtering, makes frequency converter play inhibitory action to the voltage of whole electric power system, current harmonics, meets system harmonics (THD) requirement.For the 24 pulse wave rectifier unit related in the present invention, input side Multiple coil phase shifting transformer has four road output voltages.Phase shifting transformer former limit access electrical network, identical, the voltage-phase of four road secondary output voltage effective values staggers mutually 15 ° in theory, accesses four road diode rectification unit respectively, realizes 24 pulse wave rectifiers.Phase shifting transformer owing to being subject to the impact of the condition such as material, manufacturing process, causes actual output voltage to occur uneven in actual design, manufacture process.Four road rectification units access this unbalanced threephase voltage, and unbalanced input current appears in four road rectification modules.Frequency convertor system operation under this long-time unbalanced current condition can cause local overheating phenomenon, affects frequency convertor system internal components actual life, influential system stability.The present invention regulates unbalanced electric current by sealing in differentiation reactor to realize at four road rectification module input sides, reduces voltage, current harmonics to electric network pollution.