CN109802606B - Bus capacitor energy discharge method of electric automobile driving system - Google Patents
Bus capacitor energy discharge method of electric automobile driving system Download PDFInfo
- Publication number
- CN109802606B CN109802606B CN201910037797.5A CN201910037797A CN109802606B CN 109802606 B CN109802606 B CN 109802606B CN 201910037797 A CN201910037797 A CN 201910037797A CN 109802606 B CN109802606 B CN 109802606B
- Authority
- CN
- China
- Prior art keywords
- motor
- permanent magnet
- magnet synchronous
- refi
- synchronous motor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Control Of Ac Motors In General (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Electric Propulsion And Braking For Vehicles (AREA)
Abstract
The invention discloses a bus capacitance energy release method of an electric automobile driving system, which is used for solving the technical problem of poor practicability of the conventional capacitance energy release method. The technical scheme is that after the electric automobile has an emergency, the operation state of a permanent magnet synchronous motor driving system is switched; dividing the whole discharge process into several regions; calculating the q-axis current value of the motor and the d-axis current value of the motor; and calculating the q-axis current value and the d-axis current value of the permanent magnet synchronous motor in other areas in sequence. According to the invention, the d-axis current and the q-axis current of the permanent magnet synchronous motor are respectively controlled in a segmented manner, so that the speed reduction of the permanent magnet synchronous motor is realized, the direct current bus capacitance energy is rapidly released, and the problem of large voltage feedback impact of the permanent magnet synchronous motor is solved. The invention can implement the energy discharge control based on the coil winding for the system with large rotor inertia and small system safety current, and has good practicability.
Description
Technical Field
The invention relates to a capacitive energy discharge method, in particular to a bus capacitive energy discharge method of an electric automobile driving system.
Background
The permanent magnet synchronous motor driving system for the electric automobile receives more and more attention due to the characteristics of high efficiency and wide speed regulation range. A common topological structure of a permanent magnet synchronous motor driving system of an electric automobile comprises six parts, namely a permanent magnet synchronous motor, a battery, a DC/DC power converter, a circuit breaker, a bus capacitor and an inverter. The battery is connected with the DC/DC power converter to provide energy for the system to work; the DC/DC power converter converts the low voltage of the battery into high voltage, and the output end of the DC/DC power converter is connected with the inverter; the breaker is connected with the battery and the DC/DC power converter, and is disconnected for protecting the system when in fault; the bus capacitor is connected with the inverter in parallel and used for absorbing high-frequency voltage harmonic waves; the inverter is connected with the permanent magnet synchronous motor and converts direct-current voltage into alternating-current signals. According to the united states vehicle regulation ECE R94, in case of an emergency (e.g. car accident) the circuit breaker will open immediately and the capacitor voltage should be reduced to a safe level (60V) within 5s to avoid the risk of voltage breakdown.
In order to achieve bus capacitor discharge and low-cost bleeding solutions, the documents "DCbus capacitor discharge of permanent magnet synchronous machine drive system for hybrid electric vehicles", IEEE Transactions on industrial Applications,2017, Vol53(2), p1399-1405 "disclose a new idea of consuming the remaining energy of a capacitor directly with a motor winding. The method is characterized in that when a system fault occurs, transistors in the three-phase inverter are not immediately turned off, the permanent magnet synchronous motor is continuously driven by controlling d-axis and q-axis currents, in the process, the wheel is disconnected from the traction motor through the clutch, and the motor only rotates in a no-load mode but does not drive the wheel to rotate. However, when using this algorithm, it was found that the dc bus capacitance-voltage characteristics are closely related to the system parameters, in particular the system safety current ImaxAnd the moment of inertia J of the motor rotor, when J is large and ImaxRelatively low (e.g. J ═ 0.24 kg. m)2And Imax100A), the desired discharge process cannot be achieved.
Disclosure of Invention
In order to overcome the defect that the existing capacitance energy discharge method is poor in practicability, the invention provides a bus capacitance energy discharge method of an electric automobile driving system. According to the method, after the electric automobile has an emergency, the operation state of a permanent magnet synchronous motor driving system is switched; dividing the whole discharge process into several regions; calculating the q-axis current value of the motor and the d-axis current value of the motor; and calculating the q-axis current value and the d-axis current value of the permanent magnet synchronous motor in other areas in sequence. According to the invention, the d-axis current and the q-axis current of the permanent magnet synchronous motor are respectively controlled in a segmented manner, so that the speed reduction of the permanent magnet synchronous motor is realized, the direct current bus capacitance energy is rapidly released, and the problem of large voltage feedback impact of the permanent magnet synchronous motor is solved. The invention can implement the energy discharge control based on the coil winding for the system with large rotor inertia and small system safety current, and has good practicability.
The technical scheme adopted by the invention for solving the technical problems is as follows: a bus capacitance energy discharge method of an electric automobile driving system is characterized by comprising the following steps:
step one, when a driving system works normally, a switch is switched to a port a, and a double closed-loop speed regulation strategy is adopted to drive a permanent magnet synchronous motor; when an emergency happens, the port b is connected, and bus capacitor energy begins to be discharged.
Step two, dividing the whole discharging process into n areas according to a reference track of the expected rotating speed, and selecting △ t, namely t0＝Δt、t1-t0＝Δt、…、tn-1-tn-2Δ t. At the same time t0、t1、…、tnThe rotation speed corresponding to each moment in sequence is omega0、ω1、…、ωn。
Step three, in order to avoid voltage impact, the kinetic energy of the motor rotor is less than or equal to the heat loss of the winding, namely, the absolute value of T is mete|·ωave_i·Δt≤Imax 2·Rs·Δt
In the formula, TeIs the electromagnetic torque of the motor, omegaave_iIs ti-1～tiAverage value of motor speed over time, ImaxFor system safety current, RsIs the stator winding resistance.
The q-axis negative current i in the △ t region is calculated according to a formulaq_refiIn order to reduce the motor speed as quickly as possible, iq_refiThe absolute value of (A) needs to be maximum within an allowable range, i.e.
In the formula, ΨfIs a permanent magnet flux linkage, p is the number of pole pairs of the motor, and J is the moment of inertia.
Step four, simultaneously, in order to ensure the maximum discharge capacity, the current of the system is controlled to be the safe current I in the whole processmaxIn each △ t region, the control current i on the d-axisd_refiKeeping the negative value stable, and the calculation formula is
Using calculated iq_refi、id_refiThe reference control currents are respectively used as q-axis and d-axis reference control currents of the permanent magnet synchronous motor in the ith △ t area, so that when the motor fails, direct current bus capacitor energy discharge control based on a coil winding is realized, and the expected rotating speed is reduced along with a linear trend.
Step five, mixing the materials iq_refiCarry-in Te＝1.5pΨfiq_refiCalculating motor torque TeIn the formula of psifIs a permanent magnet flux linkage, and p is the number of pole pairs of the motor. Further calculate tiCorresponding rotational speed omegai，
And repeating the third step and the fourth step to calculate the q-axis current value and the d-axis current value, namely i, of the permanent magnet synchronous motor in the next △ t regionq_refi+1And id_refi+1. Until the rotation speed of the motor is reduced to make the counter potential equal to the safe voltage.
The invention has the beneficial effects that: according to the method, after the electric automobile has an emergency, the operation state of a permanent magnet synchronous motor driving system is switched; dividing the whole discharge process into several regions; calculating the q-axis current value of the motor and the d-axis current value of the motor; and calculating the q-axis current value and the d-axis current value of the permanent magnet synchronous motor in other areas in sequence. According to the invention, the d-axis current and the q-axis current of the permanent magnet synchronous motor are respectively controlled in a segmented manner, so that the speed reduction of the permanent magnet synchronous motor is realized, the direct current bus capacitance energy is rapidly released, and the problem of large voltage feedback impact of the permanent magnet synchronous motor is solved. The invention can implement the energy discharge control based on the coil winding for the system with large rotor inertia and small system safety current, and has good practicability.
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
Drawings
FIG. 1 is a flow chart of a bus capacitor energy discharge method of an electric vehicle driving system according to the invention.
FIG. 2 is a bar graph of calculated values of q-axis reference current at different time intervals in an embodiment of the method of the present invention.
Detailed Description
Reference is made to fig. 1-2. The method for discharging the energy of the bus capacitor of the electric automobile driving system comprises the following specific steps:
considering the loss of volume, weight and cost brought by using an external circuit to discharge the energy of the direct current bus capacitor to the driving system of the electric automobile, the direct use of the winding of the permanent magnet synchronous motor to discharge the energy is very effective and has lower cost. However, no bleed-off algorithm is currently available that can be applied in drive systems with large rotor inertia and low safe currents. The mechanism and features of a conventional and novel coil winding based discharge scheme are discussed by studying an Energy Flow Model (EFM) suitable for analyzing the transient discharge behavior of a permanent magnet synchronous motor drive system. The number of pole pairs of the permanent magnet synchronous motor analyzed in the embodiment is p-3, and the driving system has larger rotor inertia J-0.24 kg · m2While the safe current is smaller Imax100A, a new non-zero d-axis and q-axis current control algorithm is provided, so that the voltage is prevented from fluctuating greatly, and the discharge time is shortened.
Step one, switching the operation state of the permanent magnet synchronous motor driving system after the electric automobile has an emergency.
When the driving system works normally, the programmable virtual switch is connected with the port a, and the driving system is normally controlled by adopting a double closed-loop speed regulation strategy. Once an emergency happens, the port b is connected, and bus capacitance energy is discharged.
And step two, selecting proper delta t, and dividing the whole discharging process into proper regions.
It should be recognized that the shorter the △ t, ωiMore typically and typically, △ t is 0.5s in this example, dividing the entire discharge region0＝0.5s、t1＝1s、t2＝1.5s、t3＝2s、t4＝2.5s、t5＝3s、t6＝3.5s、t7＝4s、t84.5s …. The rotation speed corresponding to each moment in sequence is omega0、ω1、ω2、ω3、ω4、ω5、ω6、ω7、ω8…。
Step three, calculating the q-axis current value i of the motorq_ref1. In this embodiment, the number p of pole pairs of the motor is 3, and the safe current I of the driving systemmax100A, stator winding resistance Rs0.275 omega and a moment of inertia J of 0.24kg m2。
Let omega0＝ωrated＝350rad/s，
Get iq_ref1＝-10.6A。
Step four, calculating the d-axis current value i of the motord_ref1。
Step five, calculating q-axis current i and d-axis current i of the permanent magnet synchronous motor in other areas in sequenceq_refAnd id_ref。
In this example, the permanent magnet flux linkage ΨfCalculated as 0.18Wb
iq_ref1＝-10.6A，id_ref1＝-99.44A，ω1＝332.11rad/s；iq_ref2＝-11.3A，id_ref2＝-99.36A，ω2＝313.04rad/s；iq_ref3＝-12.1A，id_ref3＝-99.27A，ω3＝292.62rad/s；iq_ref4＝-13.1A，id_ref4＝-99.17A，ω4＝270.51rad/s；iq_ref5＝-14.4A，id_ref5＝-98.96A，ω5＝246.21rad/s；iq_ref6＝-16.2A，id_ref6＝-98.68A，ω6＝218.87rad/s；iq_ref7＝-18.8A，id_ref7＝-98.21A，ω7＝187.15rad/s；iq_ref8＝-23.4A，id_ref8＝-97.22A，ω8＝147.66rad/s；iq_ref9＝-35.4A，id_ref9＝-93.52A，ω987.92 rad/s; the q-axis current and the d-axis current are used for controlling and driving the permanent magnet synchronous motor in each stage, the rotating speed of the motor is stably reduced, the voltage energy of a direct current bus can be released as fast as possible, and the safe running of the electric automobile is guaranteed.
Claims (1)
1. A bus capacitor energy discharge method of an electric automobile driving system is characterized by comprising the following steps:
step one, when a driving system works normally, a switch is switched to a port a, and a double closed-loop speed regulation strategy is adopted to drive a permanent magnet synchronous motor; once an emergency happens, connecting the port b, and starting to discharge the bus capacitor energy;
step two, dividing the whole discharging process into n areas according to a reference track of the expected rotating speed, and selecting △ t, namely t0＝Δt、t1-t0＝Δt、…、tn-1-tn-2Δ t; at the same time t0、t1、…、tnThe rotation speed corresponding to each moment in sequence is omega0、ω1、…、ωn；
Step three, in order to avoid voltage impact, the kinetic energy of the motor rotor is less than or equal to the heat loss of the winding, namely, the absolute value of T is mete|·ωave_i·Δt≤Imax 2·Rs·Δt
In the formula, TeIs the electromagnetic torque of the motor, omegaave_iIs ti-1～tiAverage value of motor speed over time, ImaxFor system safety current, RsA stator winding resistor;
the q-axis negative current i in the △ t region is calculated according to a formulaq_refiIn order to reduce the motor speed as quickly as possible, iq_refiThe absolute value of (A) needs to be maximum within an allowable range, i.e.
In the formula, ΨfThe permanent magnet flux linkage is adopted, p is the number of pole pairs of the motor, and J is the rotational inertia;
step four, simultaneously, in order to ensure the maximum discharge capacity, the current of the system is controlled to be the safe current I in the whole processmaxIn each △ t region, the control current i on the d-axisd_refiKeeping the negative value stable, and the calculation formula is
Using calculated iq_refi、id_refiThe reference control currents are respectively used as q-axis and d-axis reference control currents of the permanent magnet synchronous motor in the ith △ t area, so that when the motor breaks down, direct current bus capacitor energy discharge control based on a coil winding is realized, and the expected rotating speed is reduced along with the linear trend;
step five, mixing the materials iq_refiCarry-in Te＝1.5pΨfiq_refiCalculating motor torque TeIn the formula of psifIs a permanent magnet flux linkage, and p is the number of pole pairs of the motor; further calculate tiCorresponding rotational speed omegai，
And repeating the third step and the fourth step to calculate the q-axis current value and the d-axis current value, namely i, of the permanent magnet synchronous motor in the next △ t regionq_refi+1And id_refi+1(ii) a Until the rotation speed of the motor is reduced to make the counter potential equal to the safe voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910037797.5A CN109802606B (en) | 2019-01-16 | 2019-01-16 | Bus capacitor energy discharge method of electric automobile driving system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910037797.5A CN109802606B (en) | 2019-01-16 | 2019-01-16 | Bus capacitor energy discharge method of electric automobile driving system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109802606A CN109802606A (en) | 2019-05-24 |
| CN109802606B true CN109802606B (en) | 2020-09-25 |
Family
ID=66559404
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910037797.5A Active CN109802606B (en) | 2019-01-16 | 2019-01-16 | Bus capacitor energy discharge method of electric automobile driving system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109802606B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112829605B (en) * | 2021-02-19 | 2022-10-04 | 恒大新能源汽车投资控股集团有限公司 | Vehicle torque control method and device and computer readable storage medium |
| CN117458848A (en) * | 2023-12-26 | 2024-01-26 | 西安荣耀终端有限公司 | Power bus bleeder circuit, display device and power adapter |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010104173A (en) * | 2008-10-24 | 2010-05-06 | Juki Corp | Motor drive |
| CN101944755B (en) * | 2010-08-12 | 2013-03-20 | 上海汽车集团股份有限公司 | Method for quickly discharging for automobile high-voltage DC bus |
| JP5839873B2 (en) * | 2011-07-19 | 2016-01-06 | 東芝エレベータ株式会社 | Control device for hybrid drive elevator |
| JP5760934B2 (en) * | 2011-10-13 | 2015-08-12 | トヨタ自動車株式会社 | Drive device |
| JP6683647B2 (en) * | 2017-03-22 | 2020-04-22 | 日立オートモティブシステムズ株式会社 | Motor drive circuit control device and motor drive circuit diagnostic method |
-
2019
- 2019-01-16 CN CN201910037797.5A patent/CN109802606B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN109802606A (en) | 2019-05-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20040008530A1 (en) | Inverter control device and electric vehicle thereof | |
| US8040081B2 (en) | Motor drive apparatus, hybrid drive apparatus and method for controlling motor drive apparatus | |
| US20080218111A1 (en) | Control Device for Motor Drive System and Electric Vehicle Including the Same | |
| JP5662410B2 (en) | Electric vehicle power supply system | |
| CN109802606B (en) | Bus capacitor energy discharge method of electric automobile driving system | |
| JP2007143303A (en) | Control device of electric vehicle | |
| CN102611369B (en) | Speed-regulating system for switched reluctance motor specially used for electric vehicle | |
| JP2010247725A (en) | Power supply control device for electric vehicle | |
| CN112688409B (en) | ESO-based pure electric vehicle bus capacitor discharging system and method | |
| JP2013048608A (en) | Electric working vehicle | |
| CN106428200B (en) | Multi-phase motor control method, controller and polyphase machine electric powered steering pumping system | |
| JP2008072868A (en) | Motor controller for vehicle | |
| CN103187916A (en) | Motor control system for electric fork-lift truck | |
| CN113162385B (en) | Electric vehicle bus capacitor discharging method based on maximum copper consumption of motor winding | |
| CN114123934B (en) | Electric drive system locked rotor protection method based on current integration | |
| JP6342043B1 (en) | Electric motor control apparatus and electric motor control method | |
| JP4735076B2 (en) | Motor control device | |
| EP1124322A2 (en) | Induction motor power/torque clamping for electric vehicle performance | |
| JP4104940B2 (en) | Drive control apparatus for hybrid vehicle | |
| JP5352326B2 (en) | Motor drive control device | |
| JP7424058B2 (en) | motor control device | |
| CN202550951U (en) | Special SRM (switched reluctance motor) speed-regulating system for electric automobile | |
| Chen et al. | Novel fuzzy control strategy of IPMSM drive system with voltage booster | |
| JP2001309550A (en) | Overvoltage protector | |
| WO2021020115A1 (en) | Control device and electric vehicle |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |