Multiway power converter

• US 6,310,787 B2
• Filed: 03/29/2001
• Issued: 10/30/2001
• Est. Priority Date: 04/03/2000
• Status: Active Grant

• Current Assignee: Sanken Electric Company Limited
• Original Assignee: Sanken Electric Company Limited
• Inventors: Watanabe, Toshihiko, Ito, Youichi, Nakajima, Yasuhiro, Sato, Sinji
• Primary Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US09/820,469
• Publication Number:
  US 20010026460A1
• Time in Patent Office: 215 Days
• Field of Search: 363/16, 363/17, 363/97, 363/98, 363/131, 363/132, 363/34, 363/37
• US Class Current: 363/34
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements

Abstract

A switching power converter capable of operation in either Nonconversion, Stepdown, or Stepup Mode. Included is a parallel circuit of three serial connections of a first, a second and a third pair of switches. The junction between the first pair of switches is connected to an a.c. input terminal via an inductor, the junction between the second switch pair grounded, and the junction between the third switch pair connected to an a.c. output terminal via another inductor. The first and third switch pairs are driven at the frequency (e.g. 50 Hz) of an a.c. input voltage, and the second switch pair at a higher frequency (e.g. 20 kHz), in Nonconversion Mode; the first switch pair at the low frequency, and the second and third switch pairs at the high frequency, in Stepdown Mode; and the first and second switch pairs at the high frequency, and the third switch pair at low frequency, in Stepup Mode. The second switch pair is invariably driven at the high frequency.

Claims

1. A multiway power converter for converting an alternating input voltage from a power supply, comprising:

(a) a first and a second input terminal between which is to be connected a source of an alternating voltage for inputting an alternating input voltage (V_in);

(b) a first and a second output terminal between which is to be connected a load for applying an alternating output voltage (V_o), the second input terminal and the second output terminal being interconnected;

(c) a first and a second switch connected in series with each other and having a junction therebetween which is connected to the first input terminal;

(d) a third and a fourth switch connected in series with each other and in parallel with the serial connection of the first and the second switch, the third and the fourth switch having a junction therebetween which is connected to the interconnected second input terminal and second output terminal;

(e) a fifth and a sixth switch connected in series with each other and in parallel with the serial connections of the first and the second switch and of the third and the fourth switch, the fifth and the sixth switch having a junction therebetween which is connected to the first output terminal;

(f) a capacitor connected in parallel with the serial connections of the first and the second switch and of the third and the fourth switch and of the fifth and the sixth switch;

(g) at least two inductors connected in positions selected from among a first position between the first input terminal and the junction between the first and the second switch, a second position between the first output terminal and the junction between the fifth and the sixth switch, and a third position between the interconnected second input terminal and second output terminal and the junction between the third and the fourth switch; and

(h) a control circuit comprising at least any two of;

(i) first control means for making on-off control of the first and the second and the fifth and the sixth switch at the frequency of the input voltage (V_in), and of the third and the fourth switch at a frequency higher than that of the input voltage, in nonconversion mode in which a first voltage (V_in or V_con) between the first input terminal or the junction between the first and the second switch and the interconnected second input terminal and second output terminal is approximately equal to a second voltage (V_o or V_inv) between the first output terminal or the junction between the fifth and the sixth switch and the interconnected second input terminal and second output terminal;

(ii) second control means for making on-off control of the first and the second switch at the frequency of the input voltage (V_in), and of the third and the fourth and the fifth and the sixth switch at a frequency higher than that of the input voltage, in stepdown mode in which the second voltage (V_o or V_inv) is lower than the first voltage (V_in or V_conv); and

(iii) third control means for making on-off control of the first and the second and the third and the fourth switch at a frequency higher than that of the input voltage (V_in), and of the fifth and the sixth switch at the frequency of the input voltage, in stepup mode in which the second output voltage (V₀ or V_inv) is higher than the first voltage (V_in or V_conv).

2. The multiway power converter of claim 1 wherein the control circuit comprises:

(a) a first voltage command generator circuit for generating in synchronism with the input voltage (V_in) a first voltage command (V_rc) for setting up a desired first voltage (V_conv) between the junction between the first and the second switch and the interconnected second input terminal and second output terminal;

(b) a second voltage command generator circuit for generating in synchronism with the input voltage (V_in) a second voltage command (V_ri) for setting up a desired second voltage (V_inv) between the junction between the fifth and the sixth switch and the interconnected second input terminal and second output terminal;

(c) a rectangular wave generator for generating a rectangular wave voltage (V_s) at the same frequency as the input voltage (V_in);

(d) arithmetic means connected to the first and the second voltage command generator circuit and the rectangular wave generator for providing a first value (V_r1) and a second value (V_r3) and a third value (V_r2) by computing equations of;

3. The multiway power converter of claim 2 wherein the switch control means of the control circuit comprises:

(a) a wave generator for generating a periodic wave (V_t) at a frequency higher than that of the input voltage (V_in);

(b) a first comparator having inputs connected to the arithmetic means and the wave generator for providing a first binary switch control signal (V_Q1) which has a first voltage level when the first value (V_r1) is of greater magnitude than the periodic wave (V_t), and a second voltage level when the first value is of less magnitude than the period wave, the first comparator having an output connected to the first switch for on-off control thereof by the first switch control signal (V_Q1);

(c) a first inverter connected between the first comparator and the second switch for on-off control of the latter by a second switch control signal (V_Q2) which is a phase reversal of the first switch control signal (V_Q1);

(d) a second comparator having inputs connected to the arithmetic means and the wave generator for providing a third binary switch control signal (V_Q3) which has a first voltage level when the third value (V_r2) is of greater magnitude than the periodic wave (V_t), and a second voltage level when the third value is of less magnitude than the period wave, the second comparator having an output connected to the third switch for on-off control thereof by the third switch control signal (V_Q3);

(e) a second inverter connected between the second comparator and the fourth switch for on-off control of the latter by a fourth switch control signal (V_Q4) which is a phase reversal of the third switch control signal (V_Q3);

(f) a third comparator having inputs connected to the arithmetic means and the wave generator for providing a fifth binary switch control signal (V_Q5) which has a first voltage level when the second value (V_r3) is of greater magnitude than the periodic wave (V_t), and a second voltage level when the second value is of less magnitude than the period wave, the third comparator having an output connected to the fifth switch for on-off control thereof by the fifth switch control signal (V_Q5); and

(g) a third inverter connected between the third comparator and the sixth switch for on-off control of the latter by a sixth switch control signal (V_Q6) which is a phase reversal of the fifth switch control signal (V_Q5).

4. The multiway power converter of claim 2 wherein the switch control means of the control circuit comprises:

(a) a wave generator for generating a periodic wave (V_t) at a frequency higher than that of the input voltage (V_in);

(b) a first comparator having inputs connected to the arithmetic means and the wave generator for providing a first binary switch control signal (V_Q1) which has a first voltage level when the first value (V_r1) is of greater magnitude than the periodic wave (V_t), and a second voltage level when the first value is of less magnitude than the period wave, the first comparator having an output connected to the first switch for on-off control thereof by the first switch control signal (V_Q1);

(c) a second comparator having inputs connected to the arithmetic means and the wave generator for providing a second binary switch control signal (V_Q2) which has a first voltage level when the first value (V_r1) is of less magnitude than the periodic wave (V_t), and a second voltage level when the first value is of greater magnitude than the period wave, the second comparator having an output connected to the second switch for on-off control thereof by the second switch control signal (V_Q2);

(d) a third comparator having inputs connected to the arithmetic means and the wave generator for providing a third binary switch control signal (V_Q3) which has a first voltage level when the third value (V_r2) is of greater magnitude than the periodic wave (V_t), and a second voltage level when the third value is of less magnitude than the period wave, the third comparator having an output connected to the third switch for on-off control thereof by the third switch control signal (V_Q3);

(e) a fourth comparator having inputs connected to the arithmetic means and the wave generator for providing a fourth binary switch control signal (V_Q4) which has a first voltage level when the third value (V_r2) is of less magnitude than the periodic wave (V_t), and a second voltage level when the third value is of greater magnitude than the period wave, the fourth comparator having an output connected to the fourth switch for on-off control thereof by the fourth switch control signal (V_Q4);

(f) a fifth comparator having inputs connected to the arithmetic means and the wave generator for providing a fifth binary switch control signal (V_Q5) which has a first voltage level when the second value (V_r3) is of greater magnitude than the periodic wave (V_t), and a second voltage level when the second value is of less magnitude than the period wave, the third comparator having an output connected to the fifth switch for on-off control thereof by the fifth switch control signal (V_Q5); and

(g) a sixth comparator having inputs connected to the arithmetic means and the wave generator for providing a sixth binary switch control signal (V_Q6) which has a first voltage level when the second value (V_r3) is of less magnitude than the periodic wave (V_t), and a second voltage level when the second value is of greater magnitude than the period wave, the sixth comparator having an output connected to the sixth switch for on-off control thereof by the sixth switch control signal (V_Q5).

5. The multiway power converter of claim 2 wherein the arithmetic means of the control circuit comprises:

(a) a first arithmetic circuit connected to the first and the second voltage command generator circuit and the rectangular wave generator for putting out the first value (V_r1) by computing V_rc−

V_ri+V_s;

(b) a second arithmetic circuit connected to the first and the second voltage command generator circuit and the rectangular wave generator for putting out the second value (V_r3) by computing V_ri−

V_rc+V_s; and

(c) a third arithmetic circuit connected to the second voltage command generator circuit and the second arithmetic circuit for putting out the third value (V_r2) by computing V_r3−

V_ri.

6. The multiway power converter of claim 5 wherein the control circuit further comprises:

(a) a first limiter connected to the first arithmetic circuit for limiting the first value output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage; and

(b) a second limiter connected to the second arithmetic circuit for limiting the second value output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage.

7. The multiway power converter of claim 2 wherein the arithmetic means of the control circuit comprises:

(a) a first arithmetic circuit connected to the first and the second voltage command generator circuit for computing the equation;

8. The multiway power converter of claim 2 wherein the arithmetic means of the control circuit comprises:

(a) a first arithmetic circuit connected to the first and the second voltage command generator circuit for computing the equation;

9. The multiway power converter of claim 8 wherein the control circuit further comprises:

(a) a first limiter connected to the first adder for limiting the output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage;

(b) a second limiter connected to the second adder for limiting the output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage; and

(c) a third limiter connected to the subtracter for limiting the output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage.

10. The multiway power converter of claim 2 wherein the arithmetic means of the control circuit comprises:

(a) a first arithmetic circuit connected to the first and the second voltage command generator circuit for computing the equation;

11. The multiway power converter of claim 10 wherein the control circuit further comprises:

(a) a first limiter connected to the adder for limiting the output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage;

(b) a second limiter connected to the first subtracter for limiting the output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage; and

(c) a third limiter connected to the second subtracter for limiting the output therefrom between an upper limit that is equal to or greater than a maximum value of the rectangular wave voltage (V_s), and a lower limit that is equal to or less than a minimum value of the rectangular wave voltage.

12. The multiway power converter of claim 2 wherein the first voltage command generator circuit of the control circuit comprises:

(a) an input voltage detector circuit connected to the first and the second input terminal for detecting the input voltage (V_in);

(b) a capacitor voltage detector circuit connected to the capacitor for detecting a direct voltage across the same;

(c) a current detector circuit connected to the first input terminal for providing a voltage output in proportion with a current flowing through the first input terminal;

(d) a source of a referential direct voltage;

(e) a first subtracter having inputs connected to the capacitor voltage detector circuit and the voltage source for providing an output indicative of a difference between the voltage across the capacitor and the referential voltage;

(f) a multiplier having inputs connected to the input voltage detector circuit and the first subtracter for providing an output indicative of the product of the input voltage and the output from the first subtracter; and

(g) a second subtracter having inputs connected to the current detector circuit and the multiplier for putting out the first voltage command (V_rc) by subtracting the output from the current detector circuit from the output from the multiplier.

13. The multiway power converter of claim 2 wherein the second voltage command generator circuit of the control circuit comprises:

(a) a referential output voltage command generator for providing a command indicative of a referential output voltage;

(b) an output voltage detector circuit connected to the first and the second output terminal for detecting the actual output voltage (Vo); and

(c) a subtracter having inputs connected to the referential output voltage command generator and the output voltage detector circuit for providing the second voltage command (Vri) indicative of a difference between the referential output voltage and the actual output voltage.

14. The multiway power converter of claim 13 wherein the referential output voltage command generator of the second voltage command generator circuit is capable of putting out any selected one of a plurality of different referential output voltage commands.