An energy dissipation device, an energy dissipation power supply system and an energy dissipation method using a capacitive resonance

Abstract

The application discloses a kind of energy release devices using capacitive resonance mode, the energy release device includes capacitive energy release circuit, the capacitive energy release circuit includes No. m , No. 2 thyristor D m , capacitor C1 and No. 1 resistance R1;The parallel circuit of No. 1 thyristor D1 and No. 1 resistance R1 after parallel connection and capacitor C1 series connection with No. 1 switch tube S1 form parallel circuit, and the parallel circuit and No. 2 thyristor D m Series connection is connected on the main circuit between external DC / DC step-up / down converter and chopping commutation unit;It is also disclosed to corresponding energy release power system, energy release method;It reduces the system volume, and working state is switched flexibly, dissipates electric energy with small resistance value, avoids making other electrical components in circuit bear excessively high voltage in energy release process, and reduces heat generation.

Description

TECHNICAL FIELD

[0001] The present patent relates to the field of power electronics, in particular to a capacitor resonance type energy release device, an energy release power supply system and an energy release method. BACKGROUND

[0002] The power supply system provides the load with intermittent pulse current which alternates in positive and negative and decays regularly, and the maximum pulse current amplitude can reach several thousand amperes. During the pulse current descending stage, due to the large inductance value of the load, the maximum instantaneous power of the load is megawatt level, and without additional devices, the inductive load cannot complete the complete release of energy in a short time, so that the current in the circuit is reduced to zero. Therefore, when the load current is in the descending stage, a energy release device needs to be connected to ensure the rapid release of load energy to meet the actual engineering requirements.

[0003] The configuration scheme of the energy release device is generally divided into AC energy release configuration scheme and DC energy release configuration scheme. The installation of the energy release device on the AC side will inevitably occupy a large platform space. Therefore, the energy release device is generally connected on the DC side of the system to avoid the use of bidirectional switches and reduce the size of the system. Due to the large inductance and current of the load, if a large discharge resistor is directly connected in series in the load inductance circuit, a high voltage will be generated across the inductor, which will cause overvoltage of semiconductor devices, breakdown of insulating materials, and also generate excessive heat. Therefore, the present application converts the electrical energy into the capacitor through the capacitor inductance resonance mode, and then changes the circuit structure to dissipate the energy stored in the capacitor through a small resistance. SUMMARY

[0004] The present application aims to solve the problem that the existing energy release device occupies a large space and a large discharge resistor connected in series will generate a high voltage across the inductor, which will cause overvoltage of semiconductor devices, breakdown of insulating materials, and also generate excessive heat.

[0005] To solve the above problems, the technical scheme adopted by the present application is as follows: a capacitor resonance type energy release device, the energy release device comprises a capacitor energy release circuit, the capacitor energy release circuit comprises a first switch tube S1, a second switch tube S2, a first thyristor D1, a second thyristor D2, a capacitor C1 and a first resistor R1; the parallel circuit formed by the first switch tube S1 and the parallel circuit of the first resistor R1 and the capacitor C1 in series is connected in parallel with the second thyristor D2, and the parallel circuit and the main circuit between the external DC / DC step-down converter and the chopping commutation unit are connected in series, wherein the anode of the first thyristor D1 is connected with the capacitor C1, the cathode of the first thyristor D1 is connected with the anode of the second thyristor D2, and the cathode of the second thyristor D2 is connected with the first resistor R1. m m m m m ​​​​The main circuit of the energy releasing device is provided with a second switch tube S m .

[0006] Further, the energy releasing method of the energy releasing device adopting the capacitor resonance mode comprises the following steps:

[0007] Step A: the power supply system provides the inductive load with positive and negative alternating intermittent pulse current in a regular attenuation mode; during the pulse current charging and maintaining period, the main circuit switch tube in the energy releasing device circuit is in a closed state, at this time, the energy releasing device is short-circuited and in a standby state;

[0008] Step B: during the pulse current discharging period, the switch tubes in the branch of the energy releasing device are actuated, and the energy releasing device is put into a working state;

[0009] Step C: the main circuit switch tube S m is turned off, the thyristors D1 and D m are all turned on, the load inductance passes through D1, D m and the capacitor C1 to form an LC resonance loop, and the inductive current is resonantly reduced;

[0010] Step D: when the inductive current is reduced to 0, the thyristors D1 and D m are turned off, the switch tube S1 is closed, and the energy stored in the capacitor is consumed through the resistor R1;

[0011] Step E: when the capacitor voltage is reduced to 0, the switch tube S1 is turned off, the main circuit switch tube S m is turned on again, the energy releasing device is short-circuited in the system, and the converter enters the next pulse period.

[0012] Further, in the step A, the maximum instantaneous power required by the inductive load reaches the megawatt level, and therefore, a three-phase rectifier and a battery energy storage unit need to supply power to the load at the same time as the pulse current rises. The DC / DC step-up / down converter in the power supply system plays a role in voltage transformation. The main function of the chopping unit is to realize the direction change of the pulse current and provide the load with positive and negative alternating pulse current.

[0013] Further, in the step A, during the pulse current charging and maintaining period, the energy releasing device is short-circuited because the main circuit switch thereof is in a closed state; the energy releasing device is in a non-working state and is independent of and does not affect the power supply system.

[0014] Further, in the step B, when the pulse current ends the rising stage and starts the maintaining stage, the switch tube in the resistor branch of the energy releasing device circuit is actuated and closed to release the energy in the large inductive load.

[0015] Further, in the step C, the main circuit switch tube S mThe energy releasing device is connected to the power supply system; at this time, the electrical connection between the chopper commutation unit and the DC / DC step-up / down converter is disconnected, the power supply system no longer supplies power to the load, and the DC / DC step-up / down converter is in a standby state; the battery energy storage unit decides whether to charge it through the three-phase rectifier according to the state of charge of the battery unit.

[0016] Further, in step D, when the load inductance current is reduced to 0 through the LC resonance mode, the switch tube is actuated to change the circuit structure in the energy releasing device, and the energy absorbed by the capacitor is consumed through the resistor.

[0017] Further, in step E, when the capacitor voltage is reduced to 0, the energy absorption work of the energy releasing device is completed, at which time the switch tube S m The switch tube is again actuated to turn on, the power supply system supplies power to the large inductance load again, and the pulse current enters the next pulse period.

[0018] An energy releasing power supply system using a capacitor resonance mode, comprising a three-phase rectifier, a battery energy storage unit, a DC / DC step-up / down converter, a chopper commutation unit and a large inductance load; the input end of the three-phase rectifier is connected to the mains, and the output end thereof is connected to the input end of the battery energy storage unit; the output end of the battery energy storage unit is connected to the input end of the DC / DC step-up / down converter, the output end of the DC / DC step-up / down converter is connected to the input end of the chopper commutation unit, the output end of the chopper commutation unit is connected to the input end of the large inductance load, and the energy releasing device is arranged between the DC / DC step-up / down converter and the chopper commutation unit.

[0019] Compared with the prior art, the energy releasing device of the present application has the following advantages:

[0020] 1. The energy releasing device using a capacitor resonance mode of the present application adopts a direct current side energy releasing scheme, which can avoid the use of a bidirectional switch and reduce the system size.

[0021] 2. The energy releasing device using a capacitor resonance mode of the present application controls the connection of the energy releasing device to the power supply system through the turn-on and turn-off of the main circuit switch tube. In the power supply system power supply stage, the device and the chopper commutation unit front stage subsystem do not affect each other; in the pulse current descending stage, the energy releasing device is connected to the power supply system. The device working state switching is flexible, and the subsystems such as the converter and the energy storage unit in the system are independent and do not affect each other.

[0022] 3. The energy releasing device of the present application adopts the capacitor resonance mode to absorb the energy in the large inductance load, and then consumes the energy stored in the capacitor through a small resistance, so as to ensure the rapid release of the load current, the inductance load current rapidly drops to zero in a short time, and the circuit structure is changed to dissipate the energy through a small resistance, so as to avoid the overhigh voltage of other electrical components in the circuit during the energy releasing process, and reduce the heat generation. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is the working flow chart of the energy releasing device of the preferred embodiment of the present application;

[0024] Figure 2 is the structure diagram of the power supply system of the preferred embodiment of the present application;

[0025] Figure 3 is the topological structure diagram of the energy releasing device of the preferred embodiment of the present application; DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0027] The working flow chart of the energy releasing device in the specific embodiment of the present application is shown in Figure 1 The power supply system provides the intermittent pulse current with positive and negative alternation and gradual attenuation for the large inductance load. In the rising stage of the pulse current, the load is charged, the inductance current rises, and the inductance stores energy. At this time, the main circuit switch tube S m is turned on, and the energy releasing device does not work.

[0028] After the pulse current rises to the specified amplitude and maintains for a period of time, it enters the descending stage. When the pulse current descends, the thyristors D1 and D m are turned on, the main circuit switch tube S m is turned off, the load inductance forms an LC resonance circuit with D1 and D m and C1, and the inductance current resonates and descends.

[0029] When the inductance current descends to 0, the thyristors D1 and D m are turned off, S m and S1 are closed, the energy stored in the capacitor is dissipated through R1, and the converter enters the next pulse period. Before the next energy releasing process starts, the capacitor voltage descends to 0.

[0030] As Figure 2 As shown in the figure, a topology diagram of the energy releasing device in the form of capacitive resonance is provided. In the energy releasing device circuit, S m is a main circuit switch tube of the energy releasing device, a fully controlled device is adopted, D m and D1 are diodes.

[0031] The front stage of the energy releasing device is connected with the DC / DC step-up / down converter, and the rear stage is connected with the large inductance load through the chopping commutation unit. When the pulse current is in the rising and maintaining fixed amplitude for a period of time, the switch tube S m is always in the conducting state, and the switch tube S1 and the thyristor D m and D1 are in the off state. At this time, the energy releasing device is short-circuited due to the conduction of S m and is in the standby state.

[0032] When the pulse current is in the descending stage, the switch tube in the energy releasing device is in action, and the device enters the working state. Due to the large inductance and current, if a large discharge resistor is connected in series in the inductance loop, a high voltage will be generated at both ends of the inductance, leading to the overvoltage of the semiconductor device and the breakdown of the insulation material, and at the same time, the overhigh heat is avoided. Therefore, in order to meet the requirement that the current is reduced to 0 in a short time, the capacitive resonance form is adopted to realize the inductance energy releasing. S m is controlled to realize the connection or disconnection of the energy releasing device in the power supply system;

[0033] When the energy releasing device absorbs the energy of the load, the load inductance is connected with the capacitor through two thyristors to form an LC, and the capacitor absorbs the energy of the load inductance, so that the voltage of the capacitor gradually increases. At this time, in the power supply system, the DC / DC step-up / down converter is disconnected with the inductance load, and the power supply system stops supplying power to the load.

[0034] When the inductance current is reduced to 0, the thyristor D m and D1 in the energy releasing device are turned off, the capacitor forms a loop with the resistor R1 through S1, the stored energy in the capacitor is gradually consumed through the resistor, and the voltage of the capacitor gradually decreases to 0. When the voltage of the capacitor is 0, the switch tube S1 is turned off, S m is turned on, the energy releasing device is short-circuited in the system, and reenters the standby state, and the converter enters the next pulse period

[0035] The capacitive energy releasing circuit realizes the inductance current reduction in the form of resonance, and the LC resonance period T r is

[0036]

[0037] In order to ensure that the inductance current is reduced to 0 within 1s, the influence of the inductance resistor R L is not considered, and the following condition should be met:

[0038]

[0039] The maximum value of the capacitor voltage V C1max is

[0040]

[0041] The resistance R1 should satisfy

[0042]

[0043] In the above formula, L is the inductance, t1 is the time when the resistance R1 is put into the discharge circuit, C1 is the capacitance value, i L is the circuit current; R L is the oscillation circuit resistance, u C1 (t1) is the voltage across the capacitor;

[0044] The parameters of the capacitor energy release circuit are shown in the following table.

[0045] The simulation parameters of the capacitor energy release circuit

[0046] parameter value [R1] 0.3Ω [C1] 1.8F

[0047] The power supply system structure diagram in the embodiment of the present application is shown in Figure 3 . The power supply system mainly includes a three-phase rectifier, a battery energy storage unit, a DC / DC boost-buck converter, an energy release device, a chopping unit and other subsystems. The AC mains is stepped down by a transformer and converted into the input voltage level required by the three-phase converter. The three-phase rectifier is responsible for charging the battery energy storage device and simultaneously supplying power to the large inductance load during the rising stage of the pulse current. The DC / DC boost-buck converter converts the voltage, and the output DC current is commutated by the chopping commutator to provide the large inductance load with positive and negative alternating pulse current. The energy release device can shorten the pulse current falling time, so that the pulse falling time meets the design requirements of the actual project.

[0048] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the structural relationship and principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application.

Claims

1. A capacitor resonance energy dissipation device, characterized in that The energy dissipation device includes a capacitor energy dissipation circuit, and the capacitor energy dissipation circuit includes a first switch tube S1, a second switch tube S m , No. 1 thyristor D1, No. 2 thyristor D m , capacitor C1 and resistor R1; the circuit of the first thyristor D1 and the first resistor R1 in parallel and in series with the capacitor C1 forms a parallel circuit with the first switch tube S1, and the parallel circuit and the second thyristor D m After being connected in series, they are connected to the main circuit between the external DC / DC buck-boost converter and the chopper commutation unit, wherein the anode end of the first thyristor D1 is connected to the capacitor C1, and the cathode end of the first thyristor D1 is connected to the second thyristor D m The anode terminal is connected to the second thyristor D m The main circuit is also equipped with a second switch tube S m .

2. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to claim 1, characterized in that include: Step A: The power supply system provides the inductive load with intermittent pulse current that alternates between positive and negative and decays regularly. During the charging and maintenance period of the pulse current, the main circuit switch in the energy dissipation device circuit is in the closed state. At this time, the energy dissipation device is short-circuited and in standby mode. Step B: During the pulse current discharge period, the switch tubes in the branch of the energy dissipation device are actuated, and the energy dissipation device is put into working state; Step C: Switch tube S in the energy dissipation device circuit m Turn off, thyristor D1, D m All are turned on, and the load inductance is connected through D1 and D m Together with capacitor C1, an LC resonant circuit is formed, and the inductor current resonates and decreases; Step D: When the inductor current drops to 0, thyristors D1 and D m Turn off, the switch tube S1 is closed, and the energy stored in the capacitor is consumed through the resistor R1; Step E: When the capacitor voltage drops to 0, the switch tube S1 is turned off and the main circuit switch tube S m When it is turned on again, the energy dissipation device is short-circuited in the system and the converter enters the next pulse cycle.

3. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to claim 1, characterized in that: In step A, the maximum instantaneous power required by the inductive load reaches the megawatt level, so a three-phase rectifier and a battery energy storage unit are required to simultaneously power the load during the rising phase of the pulse current. The DC / DC buck-boost converter in the power supply system performs voltage conversion. The chopper commutation unit functions to achieve the direction change of the pulse current, providing the load with alternating positive and negative pulse current.

4. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to claim 1, characterized in that : In step A, during the pulse current charging and maintenance period, the energy dissipation device is short-circuited because its main circuit switch is in a closed state; the energy dissipation device is in a non-working state and is independent of the power supply system and does not affect each other.

5. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to claim 1, characterized in that : In step B, when the pulse current ends the rising and maintaining phases and begins to decline, the switch tube in the resistance branch in the energy dissipation device circuit closes to release the energy in the large inductive load.

6. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to claim 1, characterized in that In step C, the main circuit switch tube S in the energy dissipation device m The energy dissipation device is connected to the power supply system; at this time, the electrical connection between the chopper commutation unit and the DC / DC buck-boost converter is disconnected, and the power supply system no longer supplies power to the load; the DC / DC buck-boost converter is in standby mode; the battery energy storage unit decides whether to charge it through the three-phase rectifier based on the charge state of the battery cell.

7. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to any one of claims 1 to 6, characterized in that In step D, when the load inductor current is reduced to 0 through the LC resonance mode, the switch tube is actuated to change the circuit structure in the energy dissipation device, and the energy absorbed by the capacitor is consumed through the resistor.

8. The energy dissipation method of the energy dissipation device using a capacitor resonance method according to any one of claims 1 to 6, characterized in that In step E, when the capacitor voltage drops to zero, the energy absorption work of the energy dissipation device is completed, and the switch tube S of the main circuit of the device is turned off. m When it turns on again, the power supply system supplies power to the large inductive load again, and the pulse current enters the next pulse cycle.

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