CN109510497A - A kind of the flying capacitor voltage control system and control method of seven level ANPC current transformer - Google Patents

Abstract

Present invention discloses a kind of flying capacitor voltage control systems of seven level ANPC current transformers, including control assembly and ANPC current transformer, ANPC current transformer includes the single-phase seven level ANPC bridge arm that multiple buses are connected, control assembly includes multiple bridge arm controllers, and each single-phase seven level ANPC bridge arm is connected with a bridge arm controller, single-phase seven level ANPC bridge arm includes multiple branches interconnected, each branch includes multiple switching devices for being sequentially connected and connecing, and the multiple flying capacitors being connected in parallel are provided between two of them branch, it is realized by the conducting of bridge arm controller control switch device with shutdown and the voltage of flying capacitor is controlled, bridge arm controller control switch device includes various control state.Component number needed for the control system is few, and circuit structure is simple, it is easy to accomplish, loss is small, and the control method principle is simple, and it is clear in structure, without increasing peripheral hardware circuit, without increasing cost, and realize that efficiency is higher.

Description

A kind of the flying capacitor voltage control system and control method of seven level ANPC current transformer

Technical field

The present invention relates to the control systems and control method of a kind of flying capacitor voltage, more particularly to seven level ANPC of one kind The flying capacitor voltage control system and control method of current transformer, belong to converter topology field.

Background technique

In recent years, with the increase of driving power, more and more alternating-current actuating systems electricity even higher using 10 kV Press grade.Since the highest pressure resistance of current mature switching device is only the kV of 4.5 kV ~ 6.5, multi-level converter becomes each The research hotspot of state scholar.

Compared to traditional two level converters, multi-level converter has control, and flexibly output level number is more, output waveform Be more nearly sine wave, and device for power switching pressure voltage under the same conditions, higher output voltage can be obtained.At present The Multilevel Inverters topological structure applied on industrial circle mainly have diode-clamped, capacitor-clamped type, H bridge cascade connection type, Module combined, stacked multiple unit type and active neutral point clamp type (ANPC).ANPC topological structure is regarded as by common Three level ANPC topological structures are composed with capacitor-clamped type topological structure.ANPC topological structure preferably can overcome other to open up Flutter the problems in structure, needed for clamping device and flying capacitor it is all less, and have common DC bus, can four-quadrant fortune Row, transless operation, can export full torque under the low speed.Due to the above advantage, ANPC topological structure is highly suitable for high electricity Pressure, large capacity, high performance application.

However, the flying capacitor voltage in ANPC current transformer must be closed in order to enable ANPC current transformer to operate normally The control of reason.

In conclusion how to complete the control and control method of the flying capacitor voltage of seven level ANPC current transformers, just at For those skilled in the art's urgent problem to be solved.

Summary of the invention

Technical problem to be solved by the present invention lies in overcome the deficiencies of the prior art and provide a kind of seven level ANPC unsteady flows The flying capacitor voltage control system and control method of device can be realized under the premise of guaranteeing that ANPC current transformer operates normally Reasonable control to the flying capacitor voltage in ANPC current transformer.

The technical solution of the invention is as follows:

A kind of flying capacitor voltage control system of seven level ANPC current transformer, including control assembly and ANPC current transformer, it is described ANPC current transformer includes the single-phase seven level ANPC bridge arm that multiple buses are connected, and control assembly includes multiple bridge arm controllers, And each single-phase seven level ANPC bridge arm is connected with a bridge arm controller, the single-phase seven level ANPC bridge arm includes multiple Branch interconnected, each branch includes multiple switching devices for being sequentially connected and connecing, and is provided between two of them branch The multiple flying capacitors being connected in parallel are realized by the conducting and shutdown of bridge arm controller control switch device to flying capacitor Voltage control, bridge arm controller control switch device includes various control state.

Preferably, the single-phase seven level ANPC bridge arm includes the first branch interconnected, second branch, third branch Road, the 4th branch and the 5th branch；

The first branch includes sequentially connected switching device S_1a、S_1bWith S_1c, second branch includes sequentially connected switching device S_2a、S_2b、S_2c、S₅、S₆And S₇, third branch includes sequentially connected switching device S_3a、S_3b、S_3c、S₁₀、S₉And S₈, the 4th branch Including sequentially connected switching device S_4a、S_4bWith S_4c, the 5th branch includes first capacitor C₁With the second capacitor C₂, and second branch The first flying capacitor C is connected in parallel between third branch_f1And the second flying capacitor C_f2。

Preferably, switching device S in the first branch_1a、S_1bWith S_1cConnection type are as follows: the S_1aCollector with First capacitor C₁Anode be connected, S_1aEmitter and S_1bCollector be connected, S_1bEmitter and S_1cCollector phase Connection, S_1cEmitter respectively with S_2cCollector, S₅Collector be connected；

Switching device S in the second branch_2a、S_2b、S_2c、S₅、S₆And S₇Connection type are as follows: the S_2aEmitter difference With first capacitor C₁Cathode, the second capacitor C₂Anode, S_3aCollector be connected, S_2aCollector and S_2bEmitter phase Connection, S_2bCollector and S_2cEmitter be connected, S_2cCollector respectively with S_1cEmitter, S₅Collector be connected It connects, S₅Emitter respectively with S₆Collector, the second flying capacitor C_f2Anode be connected, S₆Emitter respectively with S₇'s Collector, the first flying capacitor C_f1Anode be connected, S₇Emitter and S₈Collector be connected；

Switching device S in third branch_3a、S_3b、S_3c、S₁₀、S₉And S₈Connection type are as follows: the S_3aCollector respectively with One capacitor C₁Cathode, the second capacitor C₂Anode, S_2aEmitter be connected, S_3aEmitter and S_3bCollector be connected It connects, S_3bEmitter and S_3cCollector be connected, S_3cEmitter respectively with S_4cCollector, S₁₀Emitter be connected It connects, S₁₀Collector respectively with S₉Emitter, the second flying capacitor C_f2Cathode be connected, S₉Collector respectively with S₈'s Emitter, the first flying capacitor C_f1Cathode be connected, S₈Collector and S₇Emitter be connected；

Switching device S in 4th branch_4a、S_4bWith S_4cConnection type are as follows: the S_4aEmitter and the second capacitor C₂Phase Connection, S_4aCollector and S_4bEmitter be connected, S_4bCollector and S_4cEmitter be connected, S_4cEmitter point Not and S_3cEmitter, S₁₀Emitter be connected；

First capacitor C in 5th branch₁With the second capacitor C₂Connection type are as follows: first capacitor C in the 5th branch₁ Anode and S_1aCollector be connected, first capacitor C₁Cathode respectively with S_2aEmitter, S_3aCollector, second electricity Hold C₂Anode be connected, the second capacitor C₂Anode respectively with S_2aEmitter, S_3aCollector, first capacitor C₁Cathode It is connected, the second capacitor C₂Cathode and S_4aEmitter be connected.

Preferably, the output voltage of the single-phase seven level ANPC bridge arm includes 3V_dc、−2V_dc、−V_dc、0、V_dc、2V_dc、 3V_dcSeven kinds of level, wherein can be achieved to be respectively 2V to the voltage-controlled level of flying capacitor_dc、−V_dc、V_dc、2V_dc, and 2V_dc、−V_dc、V_dc、2V_dcIn each level respectively correspond three kinds of state of a controls.

Preferably, the bridge arm controller control switch device includes 16 kinds of state of a controls, is respectively defined as V₀~V₁₅, often Under a state of a control, switching device in the conductive state and switching device in an off state cooperate.

Preferably, 2V_dcCorresponding state of a control is respectively V₁、V₂、V₃, V_dcCorresponding state of a control is respectively V₄、V₅、 V₆, V_dcCorresponding state of a control is respectively V₉、V₁₀、V₁₁, 2V_dcCorresponding state of a control is respectively V₁₂、V₁₃、V₁₄。

Preferably, in V₁~V₆With V₉~V₁₄State of a control under, switching device in the conductive state with it is in an off state Switching device cooperate, realize to the first flying capacitor C_f1Voltage and the second flying capacitor C_f2The control of voltage.

Preferably, the first flying capacitor C_f1With the second flying capacitor C_f2Voltage, current direction determine premise Under, including five kinds of situations:

It is V with single-phase seven level ANPC bridge arm output level_dc, electric current is outflow, with u_cf1And u_cf2Indicate two flying capacitors Voltage change, with | δ_ucf1| and | δ_ucf2|Respectively indicate u_cf1And u_cf2Percentage absolute value relative to respective setting value；

The first situation is u_cf1> 0, u_cf2>0；Second situation is u_cf1≤ 0, u_cf2≤0；The third situation is u_cf1≤ 0, u_cf2>0；4th kind of situation is u_cf1> 0, u_cf2≤0, |δu_cf1|>|δu_cf2|；5th kind of situation is u_cf1> 0, u_cf2≤0, |δu_cf1|≤|δu_cf2|。

A kind of control method of the flying capacitor voltage control system of seven level ANPC current transformer is −2V_dc、−V_dc、V_dc、2V_dcWhen four level, in V₁~V₆With V₉~V₁₄State of a control under, select switch in the conductive state Device simultaneously selects switching device in an off state, opens switching device in the conductive state in an off state It closes device to cooperate, realize to the first flying capacitor C_f1Voltage and the second flying capacitor C_f2The control of voltage.

Preferably, as the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the first situation, u_cf1> 0, ∆u_cf2When > 0, switch state V is selected₁₀；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in second situation, u_cf1≤ 0, u_cf2≤0 When, select switch state V₉；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the third situation, u_cf1≤ 0, u_cf2When > 0, Select switch state V₁₁；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the 4th kind of situation, u_cf1> 0, u_cf2≤0, | δ_ucf1|>|δ_ucf2| when, select switch state V₁₀；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the 5th kind of situation, u_cf1> 0, u_cf2≤0, | δ_ucf1|≤|δ_ucf2| when, select switch state V₉。

Compared with prior art, the present invention has advantageous effects below:

The flying capacitor voltage control system of seven level ANPC current transformers in the present invention, by each single-phase in ANPC current transformer Increase bridge arm controller in seven level ANPC bridge arms, realizes bridge arm controller to the conducting of switching device and the choosing of off state It selects, to realize the conjunction to the flying capacitor voltage in ANPC current transformer under the premise of guaranteeing that ANPC current transformer operates normally Reason controls, and component number needed for the control system is few, and circuit structure is simple, it is easy to accomplish, small, control method original is lost Reason is simple, clear in structure, without increasing peripheral hardware circuit, without increasing cost, and realizes that efficiency is higher.

Just attached drawing in conjunction with the embodiments below, the embodiment of the present invention is described in further detail, so that of the invention Technical solution is more readily understood, grasps.

Detailed description of the invention

Fig. 1 is the structure chart of the flying capacitor voltage control system of seven level ANPC current transformers in the present invention；

Fig. 2 is the topology diagram of single-phase seven level ANPC bridge arm in the present invention；

Fig. 3 is that jackshaft arm controller control switch device of the present invention is in V₀Current path when state and electric current outflow；

Fig. 4 is that jackshaft arm controller control switch device of the present invention is in V₁Current path under state and when electric current flows out；

Fig. 5 is that jackshaft arm controller control switch device of the present invention is in V₂Current path under state and when electric current is outflow；

Fig. 6 is that jackshaft arm controller control switch device of the present invention is in V₃Current path under state and when electric current is outflow；

Fig. 7 is that jackshaft arm controller control switch device of the present invention is in V₄Current path under state and when electric current is outflow；

Fig. 8 is that jackshaft arm controller control switch device of the present invention is in V₅Current path under state and when electric current is outflow；

Fig. 9 is that jackshaft arm controller control switch device of the present invention is in V₆Current path under state and when electric current is outflow；

Figure 10 is that jackshaft arm controller control switch device of the present invention is in V₇Current path under state and when electric current is outflow；

Figure 11 is that jackshaft arm controller control switch device of the present invention is in V₈Current path under state and when electric current is outflow；

Figure 12 is that jackshaft arm controller control switch device of the present invention is in V₉Current path under state and when electric current is outflow；

Figure 13 is that jackshaft arm controller control switch device of the present invention is in V₁₀Electric current under state and when electric current is outflow is logical Road；

Figure 14 is that jackshaft arm controller control switch device of the present invention is in V₁₁Electric current under state and when electric current is outflow is logical Road；

Figure 15 is that jackshaft arm controller control switch device of the present invention is in V₁₂Electric current under state and when electric current is outflow is logical Road；

Figure 16 is that jackshaft arm controller control switch device of the present invention is in V₁₃Electric current under state and when electric current is outflow is logical Road；

Figure 17 is that jackshaft arm controller control switch device of the present invention is in V₁₄Electric current under state and when electric current is outflow is logical Road；

Figure 18 is that jackshaft arm controller control switch device of the present invention is in V₁₅Electric current under state and when electric current is outflow is logical Road；

Figure 19 is that jackshaft arm controller control switch device of the present invention is in V₉Under state and electric current is when flowing out to flying capacitor The influence of voltage；

Figure 20 is that jackshaft arm controller control switch device of the present invention is in V₁₀Under state and electric current is when flowing out to flying capacitor The influence of voltage；

Figure 21 is that jackshaft arm controller control switch device of the present invention is in V₁₁Under state and electric current is when flowing out to flying capacitor The influence of voltage；

Figure 22 is the control flow of the control method of the flying capacitor voltage control system of seven level ANPC current transformers of the invention Figure；

Figure 23 is the first flying capacitor voltage C in the present invention_f1Voltage and the second flying capacitor C_f2Voltage experimental waveform Figure；

Figure 24 is the phase voltage u of seven level ANPC current transformers in the present invention_a, line voltage u_abAnd phase current i_aWaveform diagram.

Specific embodiment

A kind of flying capacitor voltage control system of seven level ANPC current transformer, as shown in Figure 1, include control assembly with ANPC current transformer, ANPC current transformer include the single-phase seven level ANPC bridge arm that multiple buses are connected, and control assembly includes multiple Bridge arm controller, and each single-phase seven level ANPC bridge arm is connected with a bridge arm controller.In technical solution of the present invention In, ANPC current transformer includes the single-phase seven level ANPC bridge arm that three buses are connected, and control assembly includes three bridge arm controls Device, a bridge arm controller are connected with a single-phase seven level ANPC bridge arm and independently carry out this single-phase seven level ANPC bridge arm The Detection & Controling of interior flying capacitor voltage can be realized in seven level ANPC current transformers by three bridge arm controllers of control and be suspended The control of capacitance voltage.

Single-phase seven level ANPC bridge arm includes multiple branches interconnected, and each branch includes that multiple be sequentially connected connects Switching device, and be provided with the multiple flying capacitors being connected in parallel between two of them branch, opened by the control of bridge arm controller The conducting for closing device is realized with shutdown controls the voltage of flying capacitor, and bridge arm controller control switch device includes various control State.

In the present embodiment, single-phase seven level ANPC bridge arm, as shown in Fig. 2, including the first branch interconnected, second Branch, third branch, the 4th branch and the 5th branch；

The first branch includes sequentially connected switching device S_1a、S_1bWith S_1c, second branch includes sequentially connected switching device S_2a、S_2b、S_2c、S₅、S₆And S₇, third branch includes sequentially connected switching device S_3a、S_3b、S_3c、S₁₀、S₉And S₈, the 4th branch Including sequentially connected switching device S_4a、S_4bWith S_4c, the 5th branch includes first capacitor C₁With the second capacitor C₂, and second branch The first flying capacitor C is connected in parallel between third branch_f1And the second flying capacitor C_f2。

Switching device S in the first branch_1a、S_1bWith S_1cConnection type are as follows: S_1aCollector and first capacitor C₁Anode It is connected, S_1aEmitter and S_1bCollector be connected, S_1bEmitter and S_1cCollector be connected, S_1cEmitter Respectively with S_2cCollector, S₅Collector be connected；

Switching device S in second branch_2a、S_2b、S_2c、S₅、S₆And S₇Connection type are as follows: S_2aEmitter respectively with first electricity Hold C₁Cathode, the second capacitor C₂Anode, S_3aCollector be connected, S_2aCollector and S_2bEmitter be connected, S_2b Collector and S_2cEmitter be connected, S_2cCollector respectively with S_1cEmitter, S₅Collector be connected, S₅Hair Emitter-base bandgap grading respectively with S₆Collector, the second flying capacitor C_f2Anode be connected, S₆Emitter respectively with S₇Collector, One flying capacitor C_f1Anode be connected, S₇Emitter and S₈Collector be connected；

Switching device S in third branch_3a、S_3b、S_3c、S₁₀、S₉And S₈Connection type are as follows: S_3aCollector respectively with first electricity Hold C₁Cathode, the second capacitor C₂Anode, S_2aEmitter be connected, S_3aEmitter and S_3bCollector be connected, S_3b Emitter and S_3cCollector be connected, S_3cEmitter respectively with S_4cCollector, S₁₀Emitter be connected, S₁₀'s Collector respectively with S₉Emitter, the second flying capacitor C_f2Cathode be connected, S₉Collector respectively with S₈Emitter, First flying capacitor C_f1Cathode be connected, S₈Collector and S₇Emitter be connected；

Switching device S in 4th branch_4a、S_4bWith S_4cConnection type are as follows: S_4aEmitter and the second capacitor C₂It is connected, S_4a Collector and S_4bEmitter be connected, S_4bCollector and S_4cEmitter be connected, S_4cEmitter respectively with S_3c Emitter, S₁₀Emitter be connected；

First capacitor C in 5th branch₁With the second capacitor C₂Connection type are as follows: first capacitor C in the 5th branch₁Anode with S_1aCollector be connected, first capacitor C₁Cathode respectively with S_2aEmitter, S_3aCollector, the second capacitor C₂Anode It is connected, the second capacitor C₂Anode respectively with S_2aEmitter, S_3aCollector, first capacitor C₁Cathode be connected, Two capacitor C₂Cathode and S_4aEmitter be connected.

When normal operation, the operation of single-phase seven level ANPC bridge arm switching device follows following two principle:

First: switching device S_1a、S_1b、S_1cIt is connected in series, switch state is identical, can uniformly use S₁Indicate its state, derailing switch Part S_2a、S_2b、S_2cIt is connected in series, switch state is identical, can uniformly use S₂Indicate its state, switching device S_3a、S_3b、S_3cSeries connection Connection, switch state is identical, can uniformly use S₃Indicate its state, switching device S_4a、S_4b、S_4cIt is connected in series, switch state It is identical, it can uniformly use S₄Indicate its state, Tandem devices S₁With S₃State is identical, S₂With S₄State is identical；Tandem devices S₁With S₂ State is complementary, S₃With S₄State is complementary, therefore available S₁Unified representation Tandem devices S₁、S₂、S₃、S₄State.

Second: switching device S₅With S₁₀、S₆With S₉、S₇With S₈State is complementary, can use S₅、S₆、S₇Indicate this three pairs of switching device The state of part.

In the present embodiment, using DC bus midpoint as reference potential, the output voltage packet of single-phase seven level ANPC bridge arm Include 3V_dc、−2V_dc、−V_dc、0、V_dc、2V_dc、3V_dcSeven kinds of level, wherein can be achieved to the voltage-controlled level of flying capacitor point It Wei not 2V_dc、−V_dc、V_dc、2V_dc, and 2V_dc、−V_dc、V_dc、2V_dcIn each level respectively correspond three kinds of state of a controls；Bridge arm control Device control switch device processed includes 16 kinds of state of a controls, is respectively defined as V₀~V₁₅, in the conductive state under each state of a control Switching device and switching device in an off state cooperate.

When bridge arm controller control switch device is V₀Switching device S when state, in the first branch_1a、S_1bWith S_1c, the The switching device S of two roads_2a、S_2b、S_2c、S₅、S₆And S₇, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀、S₉And S₈, The switching device S of 4th road_4a、S_4bWith S_4cIt is in off state；

When bridge arm controller control switch device is V₁Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅、S₆, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀、S₉, the 4th road Switching device S_4a、S_4bWith S_4cIt is in off state, switching device S₇、S₈It is in the conductive state；

When bridge arm controller control switch device is V₂Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅And S₇, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀And S₈, the 4th road Switching device S_4a、S_4bWith S_4cIt is in off state；Switching device S₆With S₉It is in the conductive state；

When bridge arm controller control switch device is V₃Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₆And S₇, the switching device S of third branch road_3a、S_3b、S_3c、S₉And S₈, the 4th road Switching device S_4a、S_4bWith S_4cIt is in off state；Switching device S₅With S₁₀It is in the conductive state；

When bridge arm controller control switch device is V₄Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀, the switch of the 4th road Device S_4a、S_4bWith S_4cIt is in off state；Switching device S₆、S₇、S₉And S₈It is in the conductive state；

When bridge arm controller control switch device is V₅Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2cAnd S₇, the switching device S of third branch road_3a、S_3b、S_3cAnd S₈, the 4th road is opened Close device S_4a、S_4bWith S_4cIt is in off state；Switching device S₅、S₆、S₁₀、S₉It is in the conductive state；

When bridge arm controller control switch device is V₆Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₆, the switching device S of third branch road_3a、S_3b、S_3c、S₉, the derailing switch of the 4th road Part S_4a、S_4bWith S_4cIt is in off state；Switching device S₅、S₁₀、S₇And S₈It is in the conductive state；

When bridge arm controller control switch device is V₇Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c, the switching device S of third branch road_3a、S_3b、S_3c, the switching device S of the 4th road_4a、 S_4bWith S_4cIt is in off state；Switching device S₅、S₆、S₇、S₁₀、S₉And S₈It is in the conductive state；

When bridge arm controller control switch device is V₈Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c, the switching device S of third branch road_3a、S_3b、S_3c, the switching device S of the 4th road_4a、 S_4bWith S_4cIt is on state；Switching device S₅、S₆And S₇、S₁₀、S₉And S₈It is in an off state；

When bridge arm controller control switch device is V₉Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀, the switch of the 4th road Device S_4a、S_4bWith S_4cIt is on state；Switching device S₆And S₇、S₉And S₈It is in an off state；

When bridge arm controller control switch device is V₁₀Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2cAnd S₇, the switching device S of third branch road_3a、S_3b、S_3cAnd S₈, the switch of the 4th road Device S_4a、S_4bWith S_4cIt is on state；Switching device S₅、S₆ 、S₁₀、S₉It is in an off state；

When bridge arm controller control switch device is V₁₁Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₆, the switching device S of third branch road_3a、S_3b、S_3c、S₉, the derailing switch of the 4th road Part S_4a、S_4bWith S_4cIt is on state；Switching device S₅、S₇ 、S₁₀And S₈It is in an off state；

When bridge arm controller control switch device is V₁₂Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅、S₆, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀、S₉, the 4th road Switching device S_4a、S_4bWith S_4cIt is on state；Switching device S₇And S₈It is in an off state；

When bridge arm controller control switch device is V₁₃Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅And S₇, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀And S₈, the 4th road Switching device S_4a、S_4bWith S_4cIt is on state；Switching device S₆And S₉It is in an off state；

When bridge arm controller control switch device is V₁₄Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₆And S₇, the switching device S of third branch road_3a、S_3b、S_3c、S₉And S₈, the 4th road Switching device S_4a、S_4bWith S_4cIt is on state；Switching device S₅And S₁₀It is in an off state；

When bridge arm controller control switch device is V₁₅Switching device S when state, in the first branch_1a、S_1bWith S_1c, second The switching device S of road_2a、S_2b、S_2c、S₅、S₆And S₇, the switching device S of third branch road_3a、S_3b、S_3c、S₁₀、S₉And S₈, the 4th The switching device S of branch road_4a、S_4bWith S_4cIt is on state；

Single-phase seven level ANPC bridge arm is respectively at switch state V₀~V₁₅And electric current it is outside when current path referring to Fig. 3 ~ figure 18, each switching device state is identified by the symbol " " below each switching device in Fig. 3 ~ Figure 18, and filling indicates in " " This switching tube is positive normal opening state, indicates that this switching device is normal turn-off state without filling in " "；Line with the arrow in figure The flow direction of item expression charging current.

Further, 2V_dcCorresponding state of a control is respectively V₁、V₂、V₃, V_dcCorresponding state of a control is respectively V₄、 V₅、V₆, V_dcCorresponding state of a control is respectively V₉、V₁₀、V₁₁, 2V_dcCorresponding state of a control is respectively V₁₂、V₁₃、V₁₄, own Switch state is as shown in table 1.The u in table 1₀Indicate output voltage；S_sIndicate switch state；∆u_cf1And u_cf2Indicate that two suspend The voltage change of capacitor, "+" indicate that voltage increases, and " " indicates that voltage reduces, and " * " indicates no influence；i₀Indicate output electric current, i₀ > 0 indicates that electric current is flowed out from output end, i₀< 0 indicates that electric current is flowed into from output end；Each switching device state " 1 " indicates conducting, " 0 " Indicate shutdown.Seen from table 1, only phase voltage output is 2V_dc、−V_dc、V_dc、2V_dcTo the first flying capacitor when four level C_f1Voltage and the second flying capacitor C_f2Voltage has an impact.There are three types of Redundanter schalter states for this four each level of level, and It is to the first flying capacitor C_f1Voltage and the second flying capacitor C_f2The influence of voltage is different.

As can also be seen from Table 1, in V₁~V₆With V₉~V₁₄State of a control under, switching device in the conductive state and place It cooperates, is realized to the first flying capacitor C in the switching device of off state_f1Voltage and the second flying capacitor C_f2Voltage Control.

In the inventive solutions, the first flying capacitor C_f1With the second flying capacitor C_f2Voltage, in current direction Under the premise of determination, including five kinds of situations:

It is V with single-phase seven level ANPC bridge arm output level_dc, electric current is outflow, with u_cf1And u_cf2Indicate two flying capacitors Voltage change, with | δ_ucf1| and | δ_ucf2|Respectively indicate u_cf1And u_cf2Percentage absolute value relative to respective setting value；

The first situation is u_cf1> 0, u_cf2>0；Second situation is u_cf1≤ 0, u_cf2≤0；The third situation is u_cf1≤ 0, u_cf2>0；4th kind of situation is u_cf1> 0, u_cf2≤0, |δu_cf1|>|δu_cf2|；5th kind of situation is u_cf1> 0, u_cf2≤0, |δu_cf1|≤|δu_cf2|。

The invention also provides a kind of control methods of the flying capacitor voltage control system of seven level ANPC current transformers, i.e., It is 2V in phase voltage output_dc、−V_dc、V_dc、2V_dcWhen four level, in V₁~V₆With V₉~V₁₄State of a control under, selection is in The switching device of on state simultaneously selects switching device in an off state, makes switching device and place in the conductive state It cooperates, is realized to the first flying capacitor C in the switching device of off state_f1Voltage and the second flying capacitor C_f2Voltage Control, the first flying capacitor C_f1Voltage and the second flying capacitor C_f2It can be according to this method in the case where five kinds of differences of voltage It is controlled.

Illustrate the controlling party of the flying capacitor voltage control system of seven level ANPC current transformers with specific embodiment below Method:

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the first situation, u_cf1> 0, u_cf2When > 0, Two flying capacitor voltages are all higher than setting value at this time, select switch state V₁₀, to flying capacitor C_f1It discharges, referring to attached drawing 20；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in second situation, u_cf1≤ 0, u_cf2≤0 When, two flying capacitor voltages are below setting value at this time, select switch state V₉, to flying capacitor C_f2It charges, referring to figure 19；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the third situation, u_cf1≤ 0, u_cf2When > 0, First flying capacitor C at this time_f1Voltage is lower than setting value, the second flying capacitor C_f2Voltage is higher than setting value, selects switch state V₁₁, to the first flying capacitor C_f1It charges, to the second flying capacitor C_f2It discharges, referring to fig. 21.

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the 4th kind of situation, u_cf1> 0, u_cf2≤ 0, |δ_ucf1|>|δ_ucf2| when, the first flying capacitor C at this time_f1Voltage is higher than setting value, the second flying capacitor C_f2Voltage, which is lower than, to be set Definite value, and the first flying capacitor C_f1Voltage change is larger, selects switch state V₁₀, preferentially to the first flying capacitor C_f1It carries out Electric discharge, referring to fig. 20.

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the 5th kind of situation, u_cf1> 0, u_cf2≤ 0, |δ_ucf1|≤|δ_ucf2| when, the first flying capacitor C at this time_f1Voltage is higher than setting value, the second flying capacitor C_f2Voltage, which is lower than, to be set Definite value, and the second flying capacitor C_f2Voltage change is larger, should select switch state V₉, preferentially to the second flying capacitor C_f2It carries out Charging, referring to Figure 19.

A kind of flying capacitor voltage control method of seven level ANPC current transformer, complete single-phase seven level ANPC bridge arm Flying capacitor voltage control flow is as shown in figure 22.As seen from Figure 22, the output voltage of single-phase seven level ANPC bridge arm is 3V_dc、-3V_dc, -0 ,+0 when to the first flying capacitor C_f1With the second flying capacitor C_f2Without influence.When single-phase seven level ANPC bridge The output voltage of arm is 2V_dc、−V_dc、V_dc、2V_dcIt can be to the first flying capacitor C when four level_f1With the second flying capacitor C_f2Electricity Pressure is controlled, when control, it is first determined cell current direction, the first flying capacitor C_f1Voltage and the second flying capacitor C_f2 Then the factors such as voltage are specifically chosen switching device state according to table 22.

The present invention simultaneously will be to the first flying capacitor C_f1Voltage and the second flying capacitor C_f2The control effect of voltage is tested Card, Figure 23 ~ Figure 24 are using seven level ANPC converter system DC bus-bar voltage 600V, 1.8 kHz of switching frequency, output frequency Rate is 50 Hz, and system load is a 380 V/3 kW asynchronous machines, and wherein Figure 23 is the first flying capacitor C_f1Voltage u_cf1 With the second flying capacitor C_f2Voltage u_cf2Experimental waveform, the first flying capacitor C_f1Voltage u_cf1With the second flying capacitor C_f2 Voltage u_cf2It is controlled in 100 V and 200 V or so respectively, it is seen then that the first flying capacitor C_f1With the second flying capacitor C_f2's Voltage has obtained good control.

Figure 24 is phase voltage u_a, line voltage u_abAnd phase current i_aWaveform, phase voltage be seven level, line voltage be 13 electricity Flat, current maxima is about 5 A.The results show is using seven level ANPC unsteady flows after control method proposed by the invention The output voltage waveforms of device are correct, and current sinusoidal degree is fine.

In conclusion in the present invention seven level ANPC current transformers flying capacitor voltage control system, component number is few, Circuit structure is simple, it is easy to accomplish, loss is small, and the control method principle is simple, and it is clear in structure, without increasing peripheral hardware electricity Road without increasing cost, and realizes that efficiency is higher.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and this Field technical staff can be designed alternative embodiment without departing from the scope of the appended claims.

Claims (10)

1. a kind of flying capacitor voltage control system of seven level ANPC current transformers, it is characterised in that: including control assembly with ANPC current transformer, the ANPC current transformer include the single-phase seven level ANPC bridge arm that multiple buses are connected, and control assembly includes Multiple bridge arm controllers, and each single-phase seven level ANPC bridge arm is connected with a bridge arm controller, single-phase seven level ANPC bridge arm includes multiple branches interconnected, and each branch includes multiple switching devices for being sequentially connected and connecing, and wherein It is provided with the multiple flying capacitors being connected in parallel between two branches, passes through the conducting and shutdown of bridge arm controller control switch device It realizes and the voltage of flying capacitor is controlled, bridge arm controller control switch device includes various control state.

2. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 1, feature exist In: the single-phase seven level ANPC bridge arm include the first branch interconnected, second branch, third branch, the 4th branch and 5th branch；

The first branch includes sequentially connected switching device S_1a、S_1bWith S_1c, second branch includes sequentially connected switching device S_2a、S_2b、S_2c、S₅、S₆And S₇, third branch includes sequentially connected switching device S_3a、S_3b、S_3c、S₁₀、S₉And S₈, the 4th branch Including sequentially connected switching device S_4a、S_4bWith S_4c, the 5th branch includes first capacitor C₁With the second capacitor C₂, and second branch The first flying capacitor C is connected in parallel between third branch_f1And the second flying capacitor C_f2。

3. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 2, feature exist In: switching device S in the first branch_1a、S_1bWith S_1cConnection type are as follows: the S_1aCollector and first capacitor C₁'s Anode is connected, S_1aEmitter and S_1bCollector be connected, S_1bEmitter and S_1cCollector be connected, S_1cHair Emitter-base bandgap grading respectively with S_2cCollector, S₅Collector be connected；

Switching device S in the second branch_2a、S_2b、S_2c、S₅、S₆And S₇Connection type are as follows: the S_2aEmitter respectively with First capacitor C₁Cathode, the second capacitor C₂Anode, S_3aCollector be connected, S_2aCollector and S_2bEmitter be connected It connects, S_2bCollector and S_2cEmitter be connected, S_2cCollector respectively with S_1cEmitter, S₅Collector be connected, S₅Emitter respectively with S₆Collector, the second flying capacitor C_f2Anode be connected, S₆Emitter respectively with S₇Current collection Pole, the first flying capacitor C_f1Anode be connected, S₇Emitter and S₈Collector be connected；

Switching device S in third branch_3a、S_3b、S_3c、S₁₀、S₉And S₈Connection type are as follows: the S_3aCollector respectively with One capacitor C₁Cathode, the second capacitor C₂Anode, S_2aEmitter be connected, S_3aEmitter and S_3bCollector be connected It connects, S_3bEmitter and S_3cCollector be connected, S_3cEmitter respectively with S_4cCollector, S₁₀Emitter be connected It connects, S₁₀Collector respectively with S₉Emitter, the second flying capacitor C_f2Cathode be connected, S₉Collector respectively with S₈'s Emitter, the first flying capacitor C_f1Cathode be connected, S₈Collector and S₇Emitter be connected；

Switching device S in 4th branch_4a、S_4bWith S_4cConnection type are as follows: the S_4aEmitter and the second capacitor C₂Phase Connection, S_4aCollector and S_4bEmitter be connected, S_4bCollector and S_4cEmitter be connected, S_4cEmitter point Not and S_3cEmitter, S₁₀Emitter be connected；

First capacitor C in 5th branch₁With the second capacitor C₂Connection type are as follows: first capacitor C in the 5th branch₁ Anode and S_1aCollector be connected, first capacitor C₁Cathode respectively with S_2aEmitter, S_3aCollector, second electricity Hold C₂Anode be connected, the second capacitor C₂Anode respectively with S_2aEmitter, S_3aCollector, first capacitor C₁Cathode It is connected, the second capacitor C₂Cathode and S_4aEmitter be connected.

4. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 1, feature exist In: the output voltage of the single-phase seven level ANPC bridge arm includes 3V_dc、−2V_dc、−V_dc、0、V_dc、2V_dc、3V_dcSeven kinds of level, Wherein, it can be achieved that being respectively 2V to the voltage-controlled level of flying capacitor_dc、−V_dc、V_dc、2V_dc, and 2V_dc、−V_dc、V_dc、2V_dc In each level respectively correspond three kinds of state of a controls.

5. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 4, feature exist In: the bridge arm controller control switch device includes 16 kinds of state of a controls, is respectively defined as V₀~V₁₅, under each state of a control, Switching device in the conductive state and switching device in an off state cooperate.

6. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 5, feature exist In: 2V_dcCorresponding state of a control is respectively V₁、V₂、V₃, V_dcCorresponding state of a control is respectively V₄、V₅、V₆, V_dcCorresponding control State processed is respectively V₉、V₁₀、V₁₁, 2V_dcCorresponding state of a control is respectively V₁₂、V₁₃、V₁₄。

7. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 6, feature exist In: in V₁~V₆With V₉~V₁₄State of a control under, switching device in the conductive state and switching device phase in an off state Mutually cooperation is realized to the first flying capacitor C_f1Voltage and the second flying capacitor C_f2The control of voltage.

8. a kind of flying capacitor voltage control system of seven level ANPC current transformer according to claim 7, feature exist In: the first flying capacitor C_f1With the second flying capacitor C_f2Voltage, under the premise of current direction determines, including five kinds Situation:

It is V with single-phase seven level ANPC bridge arm output level_dc, electric current is outflow, with u_cf1And u_cf2Indicate two flying capacitors Voltage change, with | δ_ucf1| and | δ_ucf2|Respectively indicate u_cf1And u_cf2Percentage absolute value relative to respective setting value；

The first situation is u_cf1> 0, u_cf2>0；Second situation is u_cf1≤ 0, u_cf2≤0；The third situation is u_cf1≤ 0, u_cf2>0；4th kind of situation is u_cf1> 0, u_cf2≤0, |δu_cf1|>|δu_cf2|；5th kind of situation is u_cf1> 0, u_cf2≤0, |δu_cf1|≤|δu_cf2|。

9. the control of the flying capacitor voltage control system of any seven level ANPC current transformer of one kind according to claim 1 ~ 8 Method processed, it is characterised in that: exporting in phase voltage is 2V_dc、−V_dc、V_dc、2V_dcWhen four level, in V₁~V₆With V₉~V₁₄Control Under state processed, selects switching device in the conductive state and select switching device in an off state, make to be on shape The switching device of state and switching device in an off state cooperate, and realize to the first flying capacitor C_f1Voltage and second outstanding Floating capacitor C_f2The control of voltage.

10. a kind of controlling party of the flying capacitor voltage control system of seven level ANPC current transformer according to claim 9 Method, it is characterised in that: as the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the first situation, u_cf1> 0, ∆u_cf2When > 0, switch state V is selected₁₀；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in second situation, u_cf1≤ 0, u_cf2When≤0, Select switch state V₉；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the third situation, u_cf1≤ 0, u_cf2When > 0, Select switch state V₁₁；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the 4th kind of situation, u_cf1> 0, u_cf2≤0, | δ_ucf1|>|δ_ucf2| when, select switch state V₁₀；

As the first flying capacitor C_f1With the second flying capacitor C_f2Voltage be in the 5th kind of situation, u_cf1> 0, u_cf2≤0, | δ_ucf1|≤|δ_ucf2| when, select switch state V₉。