**6. Some specific applications of Switch-Mode Rectifier**

The applications of three types of single-phase SMRs as the AC-DC front-end converters of PMSM drives and their comparative evaluation have been introduced in the previous section. In this section, a SMR fed switched-reluctance motor (SRM), a SMR based electric vehicle battery charger and a flyback SMR based battery plug-in charger are presented to further comprehend the advantages of using SMR.

#### **6.1 Switch-Mode Rectifier fed Switched-Reluctance Motor drive 6.1.1 System configuration**

Fig. 21 shows the power circuit and control scheme of a three-phase single-switch (3P1SW) fed SRM drive (Chai et al, 2010). The two power stages possess the following key features:

Fig. 21. A three-phase single-switch SMR fed drive and its control scheme


Some Basic Issues and Applications of

At three cases of ( 1500 *<sup>r</sup>*

ω

2.135 , 1500 , 13.2 *P kW rpm R d rL* = = =Ω ω

1.396 , 1000 , 22 *P kW rpm R d rL* = = =Ω ω

0.807 , 100 , 3.4 *P kW rpm R d rL* = = =Ω ω

**6.2.1 System configuration** 

storage component of the SMR.

*PF* 

1396 *P W <sup>d</sup>* = ) and ( 100 *<sup>r</sup>*

ω

quality improvements at all cases are also obtained.

*Pac* (kW) *THDi*  (%)

power levels without and with current harmonic compensation

**6.2 Switch-Mode Rectifier based EV battery charger** 

Switch-Mode Rectifiers on Motor Drives and Electric Vehicle Chargers 281

scheme and the SRM drive control schemes are normally operated, the measured power quality characteristics of the established SMR without ( 0 *Wh* = ) and with ( 1.0 *Wh* = ) current harmonic compensation are listed in Table 8.The results show that the fundamental and all other harmonic currents are all reduced and the efficiency of the SMR is increased accordingly by the harmonic compensation approach. Moreover, the line drawn power

> *Ia1*  (Arms)

0 *Wh* = 0.953 2.414 18.82 5.18 0.81 0.55 0.08 88.44 1.0 *Wh* = 0.968 2.362 10.33 5.01 0.42 0.31 0.04 90.39

0 *Wh* = 0.941 1.598 19.13 3.58 0.62 0.29 0.05 87.36 1.0 *Wh* = 0.951 1.579 11.01 3.03 0.28 0.18 0.04 88.41

0 *Wh* = 0.935 0.959 23.47 2.16 0.44 0.25 0.08 84.15 1.0 *Wh* = 0.943 0.932 19.54 1.91 0.33 0.17 0.06 86.59 Table 8. The measured power quality characteristics under SRM drive active load at various

A battery powered SRM drive for electric vehicle propulsion is shown in Fig. 23(a) (H.C. Chang & Liaw, 2009). In driving mode, the switches are set as: *Sm* → M and *Sd* → closed. The SRM (DENSEI company Japan) is rated as 4-phase, 8-6, 48V, 6000rpm, 2.3kW. The components , , *SDL b bb* and *Cd* in Fig. 23(a) form a DC/DC boost converter. The nominal battery voltage is *Vb* = ×= 12 4 48V , it is boosted and establishes the DC-link voltage with 48V 72V. ≤ ≤ *Vda* During demagnetization of each communication stroke, the winding energies can be directly sent back to the battery bank via the diodes 135 *DDD* , , and *D*<sup>7</sup> . In charging mode, the switches in Fig. 23(a) are set as: *Sm* → C and *Sd* permanently off. With the insertion of off-board part, a buck-boost SMR based charger is formed and drawn in Fig. 23(b) with the employed embedded motor drive components being highlighted. The diode *De* is added to avoid the short circuit of battery when *Q*6 is turned on. The inductances of the first two motor windings are used as the input filter components during each half AC cycle. And the third motor winding inductance is employed as the energy

The SMR control scheme shown in Fig. 23(b) consists of outer charging control scheme and inner current controlled PWM scheme. Initially, the battery is charged in constant current

= *rpm* , *RL* = 13.2Ω , 2135 *P W <sup>d</sup>* = ), ( 1000 *<sup>r</sup>*

= *rpm* , *RL* = 3.4Ω , 807 *P W <sup>d</sup>* = ), and the SMR robust voltage control

*Ia5*  (Arms)

*Ia7* (Arms)

*Ia11* (Arms) Efficiency (%)

ω

= *rpm* , *RL* = 22Ω ,

#### **6.1.2 SMR control scheme**

The SMR control scheme shown in Fig. 21 consists of a robust current harmonic cancellation scheme and a robust voltage control scheme. The undesired line current and output voltage ripples are regarded as disturbances and they are reduced via robust controls. Owing to the boostable and regulated DC-link voltage provided by the SMR, the dynamic responses of the followed SRM drive are enhanced, and its vibration and speed ripple are also reduced.


#### **6.1.3 Performance evaluation**

The SMR fed SRM drive is shown in Fig. 21. At the operation condition of ( 400 *V V <sup>d</sup>* = ,ω*<sup>r</sup>* = 1500rpm , *RL* = 13.2Ω , 2135 *P W <sup>d</sup>* = ), the measured DC-link voltages ( ) *<sup>d</sup> v t* and vibrations *a t*( ) using different AC/DC front-end converters are compared in Figs. 22(a) and 22(b). The results show that the DC-link voltage ripple and the stator vibration using conventional rectifier as a front-end (measured line power quality parameters are 0.631, *PF* = *THDi* = 134% ) are slightly reduced by employing the three-phase SMR ( 1 *Wh* = ) with PI control only ( 0 *Wv* = )( 0.953, *PF* = *THDi* = 18.82% ). Larger performance improvement is achieved by applying the robust voltage control scheme with the weighting factor being automatically set to be 0.989 *Wv* = . The results in Figs. 22(a) and 22(b) ( 0.968, *PF* = *THDi* = 10.33% ) indicate the further improvements both in DC-link voltage ripple and stator vibration.

Fig. 22. Measured DC-link voltages ( ) *<sup>d</sup> v t* and vibrations *a t*( ) of the SRM drive fed by different AC/DC front-end converters at ( 400 , *V V <sup>d</sup>* = 1500 , *<sup>r</sup>* ω = *rpm* , *RL* = 13.2Ω , 2135 *P W <sup>d</sup>* = (a) ( ) *<sup>d</sup> v t* ; (b) *a t*( )

The SMR control scheme shown in Fig. 21 consists of a robust current harmonic cancellation scheme and a robust voltage control scheme. The undesired line current and output voltage ripples are regarded as disturbances and they are reduced via robust controls. Owing to the boostable and regulated DC-link voltage provided by the SMR, the dynamic responses of the followed SRM drive are enhanced, and its vibration and speed ripple are also reduced. a. Robust current harmonic compensation scheme: The three-phase total current harmonic current *hi* is synthesized from the sensed phase-a line current *ai* . Then an injected PWM robust compensating control voltage ( ) *ch h h v w si* = is yielded, where ( ) *w s <sup>h</sup>*

b. Robust voltage control scheme: A compensation control command \* ( ) *or v v v ws* =

( ) *w s <sup>v</sup>* is updated according to load level, which is identified from the low-pass filtered control voltage ( ) *c LF c v H sv* = . The chaotic phenomena can be avoided automatically, better SMR control performance and voltage response are obtained simultaneously.

The SMR fed SRM drive is shown in Fig. 21. At the operation condition of

and vibrations *a t*( ) using different AC/DC front-end converters are compared in Figs. 22(a) and 22(b). The results show that the DC-link voltage ripple and the stator vibration using conventional rectifier as a front-end (measured line power quality parameters are 0.631, *PF* = *THDi* = 134% ) are slightly reduced by employing the three-phase SMR ( 1 *Wh* = ) with PI control only ( 0 *Wv* = )( 0.953, *PF* = *THDi* = 18.82% ). Larger performance improvement is achieved by applying the robust voltage control scheme with the weighting factor being automatically set to be 0.989 *Wv* = . The results in Figs. 22(a) and 22(b) ( 0.968, *PF* = *THDi* = 10.33% ) indicate the further improvements both in DC-link voltage

1V

Fig. 22. Measured DC-link voltages ( ) *<sup>d</sup> v t* and vibrations *a t*( ) of the SRM drive fed by

400V

400V

400V

Rectifier+SRM

ω

2ms

different AC/DC front-end converters at ( 400 , *V V <sup>d</sup>* = 1500 , *<sup>r</sup>*

*<sup>r</sup>* = 1500rpm , *RL* = 13.2Ω , 2135 *P W <sup>d</sup>* = ), the measured DC-link voltages ( ) *<sup>d</sup> v t*

ε

εis

. The weighting factor in the weighting function

*a*(*t*)

SMR (PI and robust control s) + SRM

SMR((PI control only)+SRM

(b)

= *rpm* , *RL* = 13.2Ω ,

1ms

/ <sup>2</sup> 0.98 *m s*

denotes a robust harmonic compensation weighting function.

generated from the tracking error *<sup>v</sup>*

*vd* (*t*)

(a)

**6.1.3 Performance evaluation** 

ω

ripple and stator vibration.

SMR (PI and robust control s) + SRM

SMR((PI control only)+SRM

2135 *P W <sup>d</sup>* = (a) ( ) *<sup>d</sup> v t* ; (b) *a t*( )

Rectifier+SRM

( 400 *V V <sup>d</sup>* = ,

**6.1.2 SMR control scheme** 

At three cases of ( 1500 *<sup>r</sup>* ω = *rpm* , *RL* = 13.2Ω , 2135 *P W <sup>d</sup>* = ), ( 1000 *<sup>r</sup>* ω = *rpm* , *RL* = 22Ω , 1396 *P W <sup>d</sup>* = ) and ( 100 *<sup>r</sup>* ω = *rpm* , *RL* = 3.4Ω , 807 *P W <sup>d</sup>* = ), and the SMR robust voltage control scheme and the SRM drive control schemes are normally operated, the measured power quality characteristics of the established SMR without ( 0 *Wh* = ) and with ( 1.0 *Wh* = ) current harmonic compensation are listed in Table 8.The results show that the fundamental and all other harmonic currents are all reduced and the efficiency of the SMR is increased accordingly by the harmonic compensation approach. Moreover, the line drawn power quality improvements at all cases are also obtained.


Table 8. The measured power quality characteristics under SRM drive active load at various power levels without and with current harmonic compensation
