DRIVER FOR SWITCHING ELEMENT AND CONTROL SYSTEM FOR ROTARY MACHINE USING THE SAME

• US 20130181640A1
• Filed: 01/10/2013
• Published: 07/18/2013
• Est. Priority Date: 01/12/2012
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: MAEBARA, Tsuneo, FUKUTA, Junichi
• Granted Patent: US 8,841,870 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 27/08 with pulse width modulation
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/166 Soft switching
• CPC Class Codes: H03K 17/168 in composite switches

Abstract

In a driver, a changing module changes a rate of discharging the control terminal of a switch at least between a first value and a second value lower than the first value. A measuring module measures a value of a parameter as a function of a current flowing through the conductive path of the switch during a drive signal being in an on state. A control module controls the changing module, as a function of the value of the parameter, to select the first value or the second value as the rate of discharging the control terminal of the switch upon the drive signal directing a change from the on state of the switch to an off state thereof. The control module discharges the control terminal of the switch using the selected value as the rate of discharging the control terminal of the switch.

Claims

1. A driver for selectively performing a charging task and a discharging task for an on-off control terminal of a voltage-controlled switch having a conductive path, according to a drive signal directing selectively an on state and an off state of the voltage-controlled switch, thus setting the voltage-controlled switch to one of the on state and the off state, the driver comprising:

a discharging-rate changing module adapted to change a rate of discharging the on-off control terminal of the voltage-controlled switch at least between a first value and a second value lower than the first value;

a measuring module configured to measure a value of a parameter as a function of a current flowing through the conductive path of the voltage-controlled switch during the drive signal being in the on state; and

a discharging control module configured to;

control the discharging-rate changing module, as a function of the value of the parameter, to select one of the first value and the second value as the rate of discharging the on-off control terminal of the voltage-controlled switch upon the drive signal directing a change from the on state of the voltage-controlled switch to the off state thereof; and

discharge the on-off control terminal of the voltage-controlled switch using the selected one of the first value and the second value as the rate of discharging the on-off control terminal of the voltage-controlled switch.

2. The driver according to claim 1, wherein the discharging control module is configured to:

if the value of the parameter measured by the measuring module, after the voltage-controlled switch is in the on state, is lower than a first threshold value, control the discharging-rate changing module to select the first value as the rate of discharging the on-off control terminal of the voltage-controlled switch within at least a period during which the value of the parameter measured by the measuring module is rising while the drive signal is directing the voltage-controlled switch to be in the off state.

3. The driver according to claim 1, wherein the discharging control module is configured to:

if the value of the parameter measured by the measuring module, after the voltage-controlled switch is in the on state, is equal to or higher than a first threshold value,

control the discharging-rate changing module to change the rate of discharging the on-off control terminal of the voltage-controlled switch from the first value to the second value within a period during which the value of the parameter is rising while the drive signal is directing the voltage-controlled switch to be in the off state; and

if the value of the parameter measured by the measuring module, after the voltage-controlled switch is in the on state, is lower than the first threshold value,

control the discharging-rate changing module to select the first value as the rate of discharging the on-off control terminal of the voltage-controlled switch within a period during which the drive signal is directing the voltage-controlled switch to be in the off state.

4. The driver according to claim 3, wherein:

the voltage-controlled switch includes;

a pair of high- and low-side switching elements connected in series and connected to positive and negative terminals of a DC power source, each of the high- and low-side switching elements having a sense terminal from which a current correlating with the current flowing through the conductive path is outputted; and

a pair of flywheel diodes, each of which is connected in antiparallel to a respective one of the high- and low-side switching elements,

the measuring module is configured to measure the value of the parameter as a function of the current outputted from the sense terminal of each of the high- and low-side switching elements, and

the discharging control module is configured to;

determine a timing at which the value of the parameter measured by the measuring module becomes equal to or higher than a second threshold value as a timing to change the rate of discharging the on-off control terminal of each of the high- and low-side switching elements from the first value to the second value, the first threshold value being lower than the second threshold value; and

validate the value of the parameter measured by the measuring module to be used for determining the timing to change the rate of discharging the on-off control terminal of each of the high- and low-side switching elements within only a period during which the drive signal is directing the voltage-controlled switch to be in the off state.

5. The driver according to claim 1, wherein the discharging control module is configured to:

if the value of the parameter measured by the measuring module, after the voltage-controlled switch is in the on state, is lower than a first threshold value,

control the discharging-rate changing module to select the first value as the rate of discharging the on-off control terminal of the voltage-controlled switch within a period during which the drive signal is directing the voltage-controlled switch to be in the off state; and

if the value of the parameter measured by the measuring module, after the voltage-controlled switch is in the on state, is equal to or higher than the first threshold value,

control the discharging-rate changing module to select the second value as the rate of discharging the on-off control terminal of the voltage-controlled switch within a period during which the drive signal is directing the voltage-controlled switch to be in the off state.

6. The driver according to claim 1, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with a first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

if a preset time has elapsed since a timing at which the drive signal directing the voltage-controlled switch to be in the on state occurs,

validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value within a period during which the drive signal is directing the voltage-controlled switch to be in the on state.

7. The driver according to claim 2, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with the first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

if a preset time has elapsed since a timing at which the drive signal directing the voltage-controlled switch to be in the on state occurs,

validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value within a period during which the drive signal is directing the voltage-controlled switch to be in the on state.

8. The driver according to claim 1, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with a first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

if a voltage at the on-off control terminal of the voltage-controlled switch is equal to or higher than a threshold voltage; and

the voltage-controlled switch has been completely changed to be in the on state,

validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value.

9. The driver according to claim 2, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with the first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

if a voltage at the on-off control terminal of the voltage-controlled switch is equal to or higher than a threshold voltage; and

the voltage-controlled switch has been completely changed to be in the on state,

validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value.

10. The driver according to claim 1, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with a first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

upon the drive signal directing a change from the on state of the voltage-controlled switch to the off state thereof, validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value.

11. The driver according to claim 2, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with the first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

upon the drive signal drive signal directing a change from the on state of the voltage-controlled switch to the off state thereof, validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value.

12. The driver according to claim 1, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with a first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

if a preset reference time has elapsed since a timing at which the value of the parameter measured by the measuring module became equal to or higher than the first threshold value,

validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value.

13. The driver according to claim 2, wherein the discharging control module is configured to:

compare the value of the parameter measured by the measuring module with the first threshold value to determine whether the value of the parameter is lower than the first threshold value; and

if a preset reference time has elapsed since a timing at which the value of the parameter measured by the measuring module became equal to or higher than the first threshold value,

validate the value of the parameter measured by the measuring module to be used for the comparison with the first threshold value.

14. The driver according to claim 6, wherein the voltage-controlled switch includes:

a pair of high- and low-side switching elements connected in series and connected to positive and negative terminals of a DC power source, each of the high- and low-side switching elements having a sense terminal from which a current correlating with the current flowing through the conductive path is outputted; and

a pair of flywheel diodes, each of which is connected in antiparallel to a respective one of the high- and low-side switching elements, and

the measuring module is configured to measure the value of the parameter as a function of the current outputted from the sense terminal of each of the high- and low-side switching elements.

15. The driver according to claim 7, wherein the voltage-controlled switch includes:

a pair of high- and low-side switching elements connected in series and connected to positive and negative terminals of a DC power source, each of the high- and low-side switching elements having a sense terminal from which a current correlating with the current flowing through the conductive path is outputted; and

a pair of flywheel diodes, each of which is connected in antiparallel to a respective one of the high- and low-side switching elements, and

the measuring module is configured to measure the value of the parameter as a function of the current outputted from the sense terminal of each of the high- and low-side switching elements.

16. The driver according to claim 14, further comprising:

a turnoff module configured to discharge the on-off control terminal of each of the high- and low-side switching elements using a third value as the rate of discharging the on-off control terminal of a corresponding one of the high- and low-side switching elements upon the value of the parameter measured by the measuring module being equal to or higher than a reference value, the third value being lower than the second value; and

a disabling module configured to disable the turnoff module from discharging the on-off control terminal of each of the high- and low-side switching elements within at least one of;

a first period until a reference time has elapsed since a timing at which the drive signal directed a change to the on state of the voltage-controlled switch; and

a second period during which the drive signal is directing the voltage-controlled switch to be in the off state.

17. The driver according to claim 15, further comprising:

a turnoff module configured to discharge the on-off control terminal of each of the high- and low-side switching elements using a third value as the rate of discharging the on-off control terminal of a corresponding one of the high- and low-side switching elements upon the value of the parameter measured by the measuring module being equal to or higher than a reference value, the third value being lower than the second value; and

a disabling module configured to disable the turnoff module from discharging the on-off control terminal of each of the high- and low-side switching elements within at least one of;

a first period until a reference time has elapsed since a timing at which the drive signal directed a change to the on state of the voltage-controlled switch; and

a second period during which the drive signal is directing the voltage-controlled switch to be in the off state.

18. A control system for controlling a rotary machine, the control system comprising:

a converter equipped with at least one pair of first voltage-controlled switching elements connected in series, each of the first voltage-controlled switching elements having a conductive path and an on-off control terminal; and

an inverter equipped with at least one pair of second voltage-controlled switching elements connected in series, each of the second voltage-controlled switching elements having a conductive path and an on-off control terminal; and

a driver for selectively performing a charging task and a discharging task for the on-off control terminal of each of the voltage-controlled switching elements, according to a drive signal directing selectively an on state and an off state of the voltage-controlled switch to thereby boost a DC voltage inputted to the converter, and invert the boosted DC voltage into an AC voltage to be supplied to the rotary machine, the driver for each of the first and second voltage-controlled switching elements comprising;

a discharging-rate changing module adapted to change a rate of discharging the on-off control terminal of a corresponding one of the first and second voltage-controlled switching elements at least between a first value and a second value lower than the first value;

a measuring module configured to measure a value of a parameter as a function of a current flowing through the conductive path of a corresponding one of the first and second voltage-controlled switching elements during the drive signal being in the on state; and

a discharging control module configured to;

control the discharging-rate changing module, as a function of the value of the parameter, to select one of the first value and the second value as the rate of discharging the on-off control terminal of a corresponding one of the first and second voltage-controlled switching elements upon the drive signal directing a change from the on state of a corresponding one of the first and second voltage-controlled switching elements to the off state thereof; and

discharge the on-off control terminal of a corresponding one of the first and second voltage-controlled switching elements using the selected one of the first value and the second value as the rate of discharging the on-off control terminal thereof.