Microcontroller architecture for power factor correction converter

• US 10,437,317 B2
• Filed: 04/02/2018
• Issued: 10/08/2019
• Est. Priority Date: 04/15/2016
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: Green, Charles E., Marcinkiewicz, Joseph G.
• Primary Examiner(s): Luo, David
• Application Number:
  US15/943,660
• Publication Number:
  US 20180224922A1
• Time in Patent Office: 554 Days
• Field of Search: 318729, 318727
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: G06F 13/4282 on a serial bus, e.g. I2C bus, SPI bus on daisy chain buses G06F13/4247
• CPC Class Codes: G06F 2212/7201 Logical to physical mapping or translation of blocks or pages
• CPC Class Codes: G06F 8/61 Installation
• CPC Class Codes: G06F 8/654 using techniques specially adapted for alterable solid state memories, e.g. for EEPROM or flash memories
• CPC Class Codes: G06F 9/223 Execution means for microinstructions irrespective of the microinstruction function, e.g. decoding of microinstructions and nanoinstructions; timing of microinstructions; programmable logic arrays; delays and fan-out problems
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/327 against abnormal temperatures
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 1/42 Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/4291 by using a Buck converter to switch the input current
• CPC Class Codes: H02P 23/26 Power factor control [PFC]
• CPC Class Codes: H02P 29/02 Providing protection against overload without automatic interruption of supply protection against faults of stepper motors H02P8/36
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A circuit for driving a motor of a compressor includes a microcontroller that generates a reference current value for a power factor correction (PFC) converter. A programmable logic device (PLD) receives control messages from the microcontroller. The PLD sets a value in an off-time register based on a control message from the microcontroller. The PLD controls a power switch of the PFC converter to turn off in response to receiving a comparison signal indicating that a measured current in the PFC converter exceeds the reference current value. Subsequent to controlling the power switch to turn off, the PLD waits for a period of time determined by the off-time register before controlling the power switch to turn on.

Claims

1. A circuit for driving a motor of a compressor, the circuit comprising:

a microcontroller configured to generate a reference current value for a power factor correction (PFC) converter; and

a programmable logic device configured to;

receive control messages from the microcontroller;

in response to receiving a first control message from the microcontroller, set a value into an off-time register based on data in the first control message;

control a power switch of the PFC converter to turn off in response to receiving a comparison signal indicating that a measured current in the PFC converter exceeds the reference current value; and

subsequent to controlling the power switch to turn off, wait for a period of time determined by the off-time register before controlling the power switch to turn on.

2. The circuit of claim 1 wherein the programmable logic device is configured to control the power switch to turn on once both (i) the period of time has expired and (ii) the comparison signal indicates that the measured current does not exceed the reference current value.

3. The circuit of claim 1 further comprising an analog comparator configured to output the comparison signal based on a comparison between (i) an analog signal representative of the reference current value and (ii) an analog signal representative of the measured current in the PFC converter.

4. The circuit of claim 1 wherein the programmable logic device is configured to measure at least one of a turn-off delay of the power switch and a turn-on delay of the power switch.

5. The circuit of claim 4 wherein the programmable logic device is configured to selectively transmit at least one of the measured turn-off delay and the measured turn-on delay to the microcontroller.

6. The circuit of claim 4 further comprising:

a comparator configured to compare (i) a first signal indicating a voltage across the power switch and (ii) a first threshold,

wherein the programmable logic device is configured to measure the turn-on delay of the power switch as a delay between (i) controlling the power switch to turn on and (ii) the comparator indicating that the first signal exceeds the first threshold.

7. The circuit of claim 1 wherein the programmable logic device is configured to:

receive a second message of the control messages, wherein the second message includes a plurality of bits; and

drive values of the plurality of bits respectively onto a plurality of pins that corresponds one-to-one to the plurality of bits.

8. The circuit of claim 1 wherein:

the microcontroller is configured to program the programmable logic device using a programming file encoded in a compressed file format; and

the compressed file format includes serialized instructions for execution by the microcontroller without performing a decompression operation to recover the programming file.

9. The circuit of claim 1 wherein:

the microcontroller includes an operational amplifier, a comparator, and a dedicated pin;

the operational amplifier is configured to sample the measured current;

the comparator is configured to compare the measured current from the operational amplifier to the reference current value and assert the comparison signal in response to the measured current exceeding the reference current value; and

the comparison signal is output from the microcontroller on the dedicated pin.

10. The circuit of claim 1 wherein:

the microcontroller includes a first serial interface;

the programmable logic device includes;

a second serial interface in communication with the first serial interface, and

a dedicated pin;

the programmable logic device is configured to receive the control messages from the microcontroller via the second serial interface; and

the programmable logic device is configured to receive the comparison signal on the dedicated pin.

11. A control method for a programmable logic device, the method comprising:

in response to the programmable logic device receiving a first control message from a microcontroller, setting a value based on data in the first control message into an off-time register of the programmable logic device;

in response to the programmable logic device receiving a comparison signal indicating that a measured current in a power factor correction (PFC) converter exceeds a reference current value, (i) controlling, using the programmable logic device, a power switch of the PFC converter to turn off and (ii) starting a timer; and

controlling, using the programmable logic device, the power switch to turn on in response to a value of the timer reaching the value in the off-time register.

12. The method of claim 11 further comprising controlling the power switch to turn on once both (i) the value of the timer reaches the value in the off-time register and (ii) the comparison signal indicates that the measured current does not exceed the reference current value.

13. The method of claim 11 further comprising generating the comparison signal based on a comparison between (i) an analog signal representative of the reference current value and (ii) an analog signal representative of the measured current in the PFC converter.

14. The method of claim 11 further comprising measuring, using the programmable logic device, at least one of a turn-off delay of the power switch and a turn-on delay of the power switch.

15. The method of claim 14 further comprising selectively transmitting at least one of the measured turn-off delay and the measured turn-on delay from the programmable logic device to the microcontroller.

16. The method of claim 14 wherein:

the method further comprises comparing (i) a first signal indicating a voltage across the power switch and (ii) a first threshold; and

the turn-on delay of the power switch is measured as a delay between (i) controlling the power switch to turn on and (ii) the first signal exceeding the first threshold.

17. The method of claim 11 further comprising:

receiving, using the programmable logic device, a second control message including a plurality of bits; and

driving, using the programmable logic device, values of the plurality of bits respectively onto a plurality of pins that corresponds one-to-one to the plurality of bits.

18. The method of claim 11 further comprising programming, using the microcontroller, the programmable logic device using a programming file encoded in a compressed file format, wherein the compressed file format includes serialized instructions that are executable by the microcontroller without performing a decompression operation to recover the programming file.

19. The method of claim 11 further comprising:

sampling the measured current measuring using an operational amplifier;

comparing, using a comparator of the microcontroller, the measured current to the reference current value;

asserting the comparison signal in response to the measured current exceeding the reference current value; and

outputting, on a first dedicated pin of the microcontroller, the comparison signal.

20. The method of claim 11 further comprising:

receiving, on a dedicated pin of the programmable logic device, the comparison signal; and

receiving, via a first serial interface of the programmable logic device, control messages from a second serial interface of the microcontroller, wherein the first serial interface is physically distinct from the dedicated pin.