Master AESM 9 Drives DCDC Converter DCAC Frequency

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Master AESM 9 Drives DC/DC Converter DC/AC Frequency Converter Ecole Polytechnique de l'Université d'Orléans

Master AESM 9 Drives DC/DC Converter DC/AC Frequency Converter Ecole Polytechnique de l'Université d'Orléans

Power electronics and automotive vehicles Introduction 1 The electrical supplies on a hybrid vehicle

Power electronics and automotive vehicles Introduction 1 The electrical supplies on a hybrid vehicle are 14 v and 42 v batteries, or even more, for which the converters are DC/DC, DC/AC, from 200 to 300 V 2 Power electronics uses electronic components that work by switching so with very little loss, thus ensuring good energy efficiencies. 3 Most current actuators are coils (electromagnetic injectors, small DC motors, electromagnetic valves). They use the electromagnetic properties of the current which creates forces passing in solenoids: these forces are regulated by setting the average intensity. All by wires 4 progress in the reliability and cost of electronics allows integration on the vehicle. Ecole Polytechnique de l'Université d'Orléans

Power electronics and automotive vehicles perfect component = switches i. K v. K K=

Power electronics and automotive vehicles perfect component = switches i. K v. K K= 0 switch on i. K is null P=0 K=1 switch off v. Ke null (almost) P=0 P=VK. i. K • • • In the real case the voltage at the terminals of a component has a low value. Dissipated power is not zero although weakly positive. Electronic components switch very quickly over a few hundred k. Hz. The time constants of RL circuits are on the order of the millisecond. η the cyclical ratio is adjustable The period T is constant. K law 1 0 ηT T t Ecole Polytechnique de l'Université d'Orléans

Power electronics and automotive vehicles current setting by Pulse Width Modulation i u. L

Power electronics and automotive vehicles current setting by Pulse Width Modulation i u. L u UA U 0 ηT T t Thus average current is dependent on the mean voltage value and don’t forget that the average current gives the torque Ecole Polytechnique de l'Université d'Orléans

Power electronics and automotive vehicles Summary of switching components The switch VK i. K

Power electronics and automotive vehicles Summary of switching components The switch VK i. K 2 i. K 1 VK 3 diode i. K VK VK 4 rectifier transistor Main rule: VK. i. K can only be positive so the only possible quadrants are odd: 1 and 3 Ecole Polytechnique de l'Université d'Orléans

The basic chopper cell Switch Control law Hypothesis : UA > 0 ; I

The basic chopper cell Switch Control law Hypothesis : UA > 0 ; I 0 > 0 IK 1 VK 1 UA IK 2 I 0 Short circuit VK 2 K 1 = 0 K 2 = 0 This situation is also unacceptable for the current source In conclusion Ecole Polytechnique de l'Université d'Orléans

The basic chopper cell Nature of the switches Hypothesis : UA > 0 ;

The basic chopper cell Nature of the switches Hypothesis : UA > 0 ; I 0 > 0 IK 1 K VK 1 I 0 UA IK 2 VK 2 IK 1 1 I 0 > 0 IK 2 0 VK 1 0 VK 2 UA>0 Ecole Polytechnique de l'Université d'Orléans

The basic chopper cell Switches Hypothesis : UA > 0 ; I 0 >

The basic chopper cell Switches Hypothesis : UA > 0 ; I 0 > 0 IK 1 K VK 1 I 0 UA IK 2 VK 2 Ecole Polytechnique de l'Université d'Orléans 1 0 I 0 > 0 0 IK 2 0 -I 0<0 VK 1 0 UA>0 VK 2 UA>0 0

The basic chopper cell Switch solutions Hypothesis : UA > 0 ; I 0

The basic chopper cell Switch solutions Hypothesis : UA > 0 ; I 0 > 0 K IK 1 1 0 I 0 > 0 0 IK 2 0 VK 1 0 UA>0 0 VK 2 -I 0<0 K 1 VK 1 K 2 Important note : changes in State cannot conduct in the odd quadrants Ecole Polytechnique de l'Université d'Orléans i. K 1 i. K 2 VK 2

The basic chopper cell Nature of the switches K 1 is a transistor K

The basic chopper cell Nature of the switches K 1 is a transistor K 2 is a reverse diode impossible coherent structure : buck chopper ret Components are series Ecole Polytechnique de l'Université d'Orléans

Properties of the step-down transformer chopper Real supplies The source of voltage UA represents

Properties of the step-down transformer chopper Real supplies The source of voltage UA represents the accumulator battery, 12 V, a few hundred volts on hybrid vehicles The current source is a model of inductive load associated with its resistance which is suggested by the continuity of the current property in an inductor. i. A i u. C u. L UA UA UC 0 ηT Electrical time constant L/R denoted T some ms with T<102μS <u. C>=ηUA Ecole Polytechnique de l'Université d'Orléans T t

Properties of the step-down transformer chopper Realistic current hypothesis Consider the time interval [

Properties of the step-down transformer chopper Realistic current hypothesis Consider the time interval [ 0, ηT] steady state, therefore, with an initial condition on the current : i(0)=I 0 The transistor is closed and the diode is blocked: i UA u. C With A constant to be defined from the initial condition on the current: In the cases for which ηT<< (10μS compared to 1 m. S) so linear solution Ecole Polytechnique de l'Université d'Orléans

Properties of the step-down transformer chopper Load case LE (DC motor) The scheme becomes

Properties of the step-down transformer chopper Load case LE (DC motor) The scheme becomes i. A i. C two intervals of study [0, ηT] , [ηT , T] u. L UA UA E u. C steady state with an initial condition u. C Ldi/dt E Ecole Polytechnique de l'Université d'Orléans

Properties of the step-down transformer chopper Current i(t) <i> the current is triangular with

Properties of the step-down transformer chopper Current i(t) <i> the current is triangular with a ripple denoted ΔI I 0 0 ηT T t We seek to reduce the ripple to ensure the law <uc>=ηUA , This is obtained when the frequency increases. cases of low currents: Uc UA If the conduction is not continuous the mean voltage depends on the setting which is not a good thing E 0 Ecole Polytechnique de l'Université d'Orléans

Another view of the chopper : switching on inductive loads • The problem: Objects

Another view of the chopper : switching on inductive loads • The problem: Objects controlled by the calculator (Engine Calculator Unit) are inductive loads so the output is made by a transistor: +12 V L R a transistor that conducts supports a VCEsat voltage a transistor that opens imposes a di/dt about -102 A/μS 1 Law i (t) to determine when the transistor is closed • ECU 2 Initial condition: non-null current at the opening of the transistor. What is the voltage u. L at the terminals of the induction coil? 3 What is the result on the transistor? Is there a solution with a diode? Ecole Polytechnique de l'Université d'Orléans

Switching of inductive loads case of the free-wheel diode +12 V L Study the

Switching of inductive loads case of the free-wheel diode +12 V L Study the variables i (t)and v. CE, on the two closed phases on off. R v. CE Deduce an order of magnitude of the duration of the current in the inductive load The model of a diode is a generator voltage of 0, 6 V How can this time be reduced? Ecole Polytechnique de l'Université d'Orléans

Switching of inductive loads case of the Zener diode • Improvement of the cancellation

Switching of inductive loads case of the Zener diode • Improvement of the cancellation time with an 80 V Zener diode u. L draw i(t) , v. CE(t) and infer the current from the cancellation time of the current What is the constraint on the transistor? Ecole Polytechnique de l'Université d'Orléans

From the unit cell to the boost converter Consider the unit with the hypothesis

From the unit cell to the boost converter Consider the unit with the hypothesis : I 0<0 K K 1 UA IK 1 I 0 K 2 Ecole Polytechnique de l'Université d'Orléans 1 I 0 < 0 0 0 IK 2 0 VK 1 0 UA>0 VK 2 UA>0 0 -I 0>0

From the unit cell to the boost converter UA >0 et I 0<0 K

From the unit cell to the boost converter UA >0 et I 0<0 K 1 is a reverse diode i. A impossible K 2 UA i. K 2 I 0 K 2 is a transistor Ecole Polytechnique de l'Université d'Orléans

From the unit cell to the boost converterreal supplies • The current source is

From the unit cell to the boost converterreal supplies • The current source is given using a continuous voltage source of the accumulator battery type, placed in series with an inductor. The voltage source is a capacitive load, as in future actuators for automotive injectors. • Change of notation: • We designate the current source as an energy source. Thus its current is denoted IA instead of I 0 and vice versa for the voltage source. • Method: The closure of K 2 loads the inductor in magnetic energy. The continuity of the current IA means that the diode must be on. Thus this energy can be transferred to the voltage supply. i. A UA I 0 u. L Ecole Polytechnique de l'Université d'Orléans u. K 2 u. C

Properties of the boost step-up transformer voltage aspects u. L i. A UA I

Properties of the boost step-up transformer voltage aspects u. L i. A UA I 0 u. L UA u. K 2 u. C 0 ηT UA-UC Property of the inductor : Application to the graph of u. L: Thus the voltage Uc is greater than UA Thus it is possible to obtain from 12 v-48 v by adjusting the ¼ value η Ex : Prius voltage battery = 200 v motor voltage 500 v Ecole Polytechnique de l'Université d'Orléans T t

Reversible current converter • • • In the previous two structures the power<u. CI

Reversible current converter • • • In the previous two structures the power<u. CI 0> is always of the same sign: buck chopper (series chopper): <u. CI 0> =ηUAI 0 boost chopper (parallel: <u. CI 0> = UAI 0/(1 -η) It is useful, when we wish to recover energy for example, to slow down the electric actuator (recovery of kinetic energy from the moving parts). We therefore reverse the sign of the current on the same structure which becomes reversible to change the sign of the power P These two studies were carried out and gave the following results: K The presence of I 0 in two boxes requires that the two switches be bi-directional in current in order to ensure the static features of the current Ecole Polytechnique de l'Université d'Orléans IK 1 IK 2 VK 1 VK 2 1 0 0 0 UA>0 0 -I 0 UA>0 0 I 0

Reversible current onverter nature of the necessary components K 1 This type of component

Reversible current onverter nature of the necessary components K 1 This type of component is not provided by semiconductor physics i. K 1 Need to create them: v. K 1 The two upper lines militate in favour of a transistor, which is a controllable component The lower branch associated with the horizontal is a reverse diode. K 2 i. K 2 The same horizontal axis corresponds to a parallel implementation: thus the component v. K 2 Ecole Polytechnique de l'Université d'Orléans

Reversible current converter So the scheme: For the State K 1=1 If I 0

Reversible current converter So the scheme: For the State K 1=1 If I 0 is positive the transistor is conducting v. K 1 I 0 UA If I 0 is negative the diode is conducting in switch 1 The same thing with the others P=<u. CI 0> can take two signs VK 2 u. C Ecole Polytechnique de l'Université d'Orléans This is energy reversibility

Reversible converter : H scheme We use two schemes to obtain a bi-directional voltage

Reversible converter : H scheme We use two schemes to obtain a bi-directional voltage on u. M. Red for the positive version, and blue for the negative version K 1 u M K 2 v. K 1 I 0 u. M>o the Red Bridge is associated with the State on of K’ 2 u. M<o the Blue Bridge is associated with the State on of K’ 1 UA K’ 1 The conflict is the simultaneous presence of the parallel dashed lines on the lower switches which is produced by a command of these switches. K’ 2 There are several types of command Let’s consider the complementary one VK 2 Ecole Polytechnique de l'Université d'Orléans

Reversible converter : H scheme complementary control: K 1=K’ 2=K’ 1=K 2 Whatever the

Reversible converter : H scheme complementary control: K 1=K’ 2=K’ 1=K 2 Whatever the current sign it is possible because of the bi-directional possibility of the switches K 1=1→ UM=UA K 1=0→ UM= -UA u. M UA Hence the timing diagrams over a period UA 0 ηT T -UA Ecole Polytechnique de l'Université d'Orléans 2 T 3 T

DC/AC converters objectives Progressive hybridization of vehicles requires 13 kw, 33 KW powerful electrical

DC/AC converters objectives Progressive hybridization of vehicles requires 13 kw, 33 KW powerful electrical machines in a TOYOTA Prius. Powerful motors are achievable with reduced volume and mass in three-phase power Also these power supplies are reversible energy, allowing regenerative braking The most widespread engines currently are three-phase synchronous engines. They therefore require the presence of DC/AC converters for power supply. This is also the case of the starter generator of the stop 'n go function. Ecole Polytechnique de l'Université d'Orléans

DC/AC converters principles The structure of the bridge in H is well-suited to this

DC/AC converters principles The structure of the bridge in H is well-suited to this subject because the load is an inductor coil and the supply is a continuous voltage source The main difference with DC/DC converters comes from the frequency value F(1/T) which is on the order of 100 Hz. Remember that this frequency is related to the rotation speed Ω (in rad/s) of synchronous machines. The two are associated by the relationship: Ω=2πF/p u. C UA i The objective is to produce an alternative voltage u. C which initially will be square. The current consumed , i , while not sinusoidal will be considered as such. Improvements will follow to achieve this goal. These constraints imply that switches are transistors with reverse parallel diodes Ecole Polytechnique de l'Université d'Orléans

DC/AC converters energy reversibility • The single phase can be materialized with fewer switches

DC/AC converters energy reversibility • The single phase can be materialized with fewer switches if a midpoint is createdi on the source with 2 capacitors i K Full wave control UC 1 u. C K UA/2 0 T/2 T -UA/2 i. C RMS value UC = UA/2 UA UC 2 i. K’ K’ RMS value of the first term of the Fourier transform Hypothesis : ic is a sine The sign of P depends on φ1 The bridge is reversible energy Ecole Polytechnique de l'Université d'Orléans

Relationship between current in the source and in the load i i. K Equations

Relationship between current in the source and in the load i i. K Equations in current when K is closed i. C 1 UC 1 u. C K UA i. C UC 2 i. C 2 ’ K’ i. K’ The instantaneous current in the source is half of the current in the load: When K is closed if i. C is positive i also, therefore the source is generating If i. C is negative i also, therefore the source is receiving Ecole Polytechnique de l'Université d'Orléans

DC/AC converters Pulse Width Modulation control 1/2 Idea : Sinusoidal current cannot be obtained

DC/AC converters Pulse Width Modulation control 1/2 Idea : Sinusoidal current cannot be obtained in full wave command without recourse to expensive passive filtering The PWM technique addresses a sinusoidal voltage wave which has high harmonics that are more easily filterable in current. It is based on a simple principle of analogue electronics: The trigger Utr is a triangular wave with a frequency FP = m. F where F is the frequency of the desired current. Utr ucd u. W is the reference wave ucd is the comparison result Uw si utr > u. W ucd sets the voltage -UA/2 si utr< uw ucd sets the voltage UA/2 on the load u. C Ecole Polytechnique de l'Université d'Orléans

DC/AC converters U PWM waves utr t 1 definition Uw 0 t 1 TP/4

DC/AC converters U PWM waves utr t 1 definition Uw 0 t 1 TP/4 t 2 Tp 2 Tp 3 Tp u. C UA/2 Average value u. C -UA/2 Relationship between mean value uc and the reference wave The local average of uc is proportional to Uw Ecole Polytechnique de l'Université d'Orléans

DC/AC converters application to the sine reference The switching frequency of FP of the

DC/AC converters application to the sine reference The switching frequency of FP of the triangle is very high before the desired frequency F. It uses the previous relationship when uw varies slowly to changes in the triangle. Utr U Uw m=20 0 TP T/4 t u. C UA/2 θ 1 θ 2 θ 3 θ 4 θ 5 θ 6 π/2 UA/2 called index adjustment Ecole Polytechnique de l'Université d'Orléans almost 60% here

DC/AC converters Fourier analysis u. C The shape of the uc voltage is not

DC/AC converters Fourier analysis u. C The shape of the uc voltage is not very sinusoidal. This can be illustrated by using the Fourier transform : m odd Where i are even integers from 1 to m-1 Where j is odd integers from 1 to m - 2 Spectrum of the amplitudes in the Fourier series of uc These voltage terms disappear in current because of their high frequencies on inductive loads F 3 F 5 F Fp Ecole Polytechnique de l'Université d'Orléans 2 Fp-1

Three-phase DC/AC converters Some of the results established on the monophase bridge are used

Three-phase DC/AC converters Some of the results established on the monophase bridge are used for the three-phase drive with the virtual point. This gives the simple voltage VAN VBN VCN. The voltage source is UA The three loads have the same inductances (three-phase motor) UA/2 UA M A B A i. A B i. B VAN VVBNBN C UA/2 N C i. C VCN motor Ecole Polytechnique de l'Université d'Orléans

Three-phase DC/AC converters From virtual voltages to simple voltages • The three phases are

Three-phase DC/AC converters From virtual voltages to simple voltages • The three phases are identical and in a star WYE connection: • Relations between the voltages: • Inserting them in the definitions of simple voltages gives: it is possible to draw the simple voltages Ecole Polytechnique de l'Université d'Orléans

Three-phase DC/AC converters voltage drawings VAM UA/2 -UA/2 VBM U VCM UA UAB 2

Three-phase DC/AC converters voltage drawings VAM UA/2 -UA/2 VBM U VCM UA UAB 2 UA/3 -UA VAN -UA/3 UA/6 VNM -UA/6 Ecole Polytechnique de l'Université d'Orléans UA/3

Three-phase DC/AC converters Summary Voltages expressed from the midpoint M of the supply are

Three-phase DC/AC converters Summary Voltages expressed from the midpoint M of the supply are shifted one-third of a period in a full-wave command strategy. The compound voltage UAB has a 3 -level shape. The simple voltage VAN has 4 levels and looks more like a sinusoid smoothed by the inductive nature of the windings. VNM commutes from UA/6 to - UA/6 with a frequency 6 F with EMI effects. We can superimpose these measured PWM controls to improve the sinusoidal current pattern, which ensures a better transfer of power. If the current is sinusoidal, the RMS value participates fully in the transfer of power: P= 3 VC 1 Icosφ1 Ecole Polytechnique de l'Université d'Orléans