SERIALIZER-DESERIALIZER FOR MOTOR DRIVE CIRCUIT
20180278195 ยท 2018-09-27
Inventors
- Tobias Bernhard Fritz (Mainburg, DE)
- Martin Staebler (Freising, GE)
- Baher Haroun (Allen, TX)
- Peter Fundaro (Dallas, TX, US)
- Jiri Panacek (Freising, DE)
- Ralf Peter Brederlow (Poing, DE)
Cpc classification
H04L7/06
ELECTRICITY
H04Q2213/036
ELECTRICITY
H02P27/085
ELECTRICITY
H04L7/033
ELECTRICITY
International classification
H04L7/033
ELECTRICITY
Abstract
A motor drive circuit includes a first serializer-deserializer (SER-DES) module that converts first SER-DES input signals into a first SER-DES output serial data stream. The first SER-DES input signals relate to motor control inputs or motor drive power outputs. A second SER-DES module converts a second SER-DES input serial data stream corresponding to the first SER-DES output serial data stream into second SER-DES output signals. The second SER-DES input signals relate to motor drive power outputs or motor control inputs. A serial isolation channel provides a galvanic isolation barrier between the first SER-DES module and the second SER-DES module. The serial isolation channel communicates the first SER-DES output serial data stream across the galvanic isolation barrier to provide the second SER-DES input serial data stream.
Claims
1. A motor drive communication circuit, comprising: a first serializer-deserializer (SER-DES) module to convert first SER-DES input signals into a first SER-DES output serial data stream, wherein the first SER-DES input signals relate to motor control inputs or motor drive power outputs; a second SER-DES module to convert a second SER-DES input serial data stream corresponding to the first SER-DES output serial data stream into second SER-DES output signals, wherein the second SER-DES input signals relate to motor drive power outputs or motor control inputs; and a serial isolation channel to provide a galvanic isolation barrier between the first SER-DES module and the second SER-DES module, and to communicate the first SER-DES output serial data stream across the galvanic isolation barrier to provide the second SER-DES input serial data stream.
2. The motor drive communication circuit of claim 1, wherein each of the first and second SER-DES modules includes a configuration register that is programmed by a configuration input to specify: a number of controller module inputs and/or outputs to connect from a controller module, and a number of power module inputs and/or outputs to connect from a power module.
3. The motor drive communication circuit of claim 1, wherein the configuration input is a bidirectional signal to enable verification of the configuration settings that are programmed.
4. The motor drive communication circuit of claim 1, wherein each of the first and second SER-DES modules includes an input stage to encode data received from input circuits into the output serial data stream, the input circuits to be driven from respective module outputs of the first and second SER-DES modules.
5. The motor drive communication circuit of claim 4, wherein each of the first and the second SER-DES modules includes a transmit shift register coupled to the input stage thereof to transmit the output serial data stream to the serial isolation channel.
6. The motor drive communication circuit of claim 5, wherein each of the first and second SER-DES modules includes a receive shift register coupled to receive the input serial data stream from the serial isolation channel coupled to the first or second SER-DES modules.
7. The motor drive communication circuit of claim 6, comprising a controllable loopback connection between the transmit shift register and the receive shift register to enable diagnostics of communications for the SER-DES modules.
8. The motor drive communication circuit of claim 6, wherein each of the first and second SER-DES modules includes an output stage coupled to the receive shift register thereof to decode the serial input data stream and to provide parallel signals to respective module outputs of the respective first and second SER-DES module.
9. The motor drive communication circuit of claim 4, wherein the input stage is coupled to format a packet frame to be communicated in the output serial data stream, and the packet frame includes: data to specify an edge location for a signal to begin at a given time period within the packet frame; and an edge polarity to specify a rising or falling edge for the signal at the edge location.
10. The motor drive communication circuit of claim 9, wherein the packet frame is formatted according to a time division multiplexing (TDM) protocol or a frequency division multiplexing (FDM) protocol.
11. The motor drive communication circuit of claim 9, wherein the packet frame includes an error detection and correction code to enable detection and correction of bit errors that occur in the input or output serial data stream.
12. The motor drive communication circuit of claim 9, wherein the packet frame is compressed using a data compression protocol.
13. The motor drive communication circuit of claim 1, wherein each of the first and second SER-DES modules includes a phased-locked loop (PLL) to synchronize the serial data streams communicated between the respective modules.
14. The motor drive communication circuit of claim 1, wherein the isolation channel is assigned to one or more isolation domains associated with each phase of a motor, each phase of the motor having a separate high side and low side driver to define the isolation domains for each phase, one or more of the isolation domains sharing a common ground path to reduce a number of isolation channels for communicating the serial data streams.
15. The motor drive communication circuit of claim 1, wherein the first and second SER-DES modules and the serial isolation channel are implemented on an integrated circuit substrate.
16. A motor drive system, comprising: a motor controller module that includes motor controller outputs and motor controller inputs; a motor drive power module that includes motor drive power outputs and motor drive power inputs; a first serializer-deserializer (SER-DES) module to convert a first SER-DES input serial data stream into first SER-DES output signals, and/or to convert first SER-DES input signals into a first SER-DES output serial data stream, the first SER-DES output signals being to drive the motor controller inputs of the motor controller module, and the first SER-DES input signals to be driven from the motor controller outputs of the motor controller module; a second SER-DES module to convert a second SER-DES input serial data stream into second SER-DES output signals, and/or to convert second SER-DES input signals into a second SER-DES output serial data stream, the second SER-DES output signals being to drive the motor drive power inputs of the motor drive power module, and the second SER-DES input signals to be driven from the motor drive power outputs of the motor drive power module; and a serial isolation channel to provide a galvanic isolation barrier between the first SER-DES module and the second SER-DES module, and to communicate: the first SER-DES output serial data stream in one direction across the galvanic isolation barrier to provide the second SER-DES input serial data stream; and/or the second SER-DES output serial data stream in another direction across the galvanic isolation barrier to provide the first SER-DES input serial data stream.
17. The motor drive system of system of claim 16, wherein each of the first and second SER-DES modules includes a configuration register that is programmed by a configuration input to specify: a number of controller module inputs and/or outputs to connect from a controller module, and a number of power module inputs and/or outputs to connect from a power module.
18. The motor drive system of claim 16, wherein each of the first and second SER-DES modules includes an input stage to encode data received from input circuits into the output serial data stream, the input circuits to be driven from respective module outputs of the first and second SER-DES modules.
19. The motor drive system of claim 18, wherein each of the first and the second SER-DES modules includes a transmit shift register coupled to the input stage thereof to transmit the output serial data stream to the serial isolation channel.
20. The motor drive system of claim 19, wherein each of the first and second SER-DES modules includes a receive shift register coupled to receive the input serial data stream from the serial isolation channel coupled to the first or second SER-DES modules.
21. The motor drive system of claim 20, wherein each of the first and second SER-DES modules includes an output stage coupled to the receive shift register thereof to decode the serial input data stream and to provide parallel signals to respective module outputs of the respective first and second SER-DES module.
22. The motor drive system of claim 18, wherein the input stage is coupled to format a packet frame to be communicated in the output serial data stream, and the packet frame includes: data to specify an edge location for a signal to begin at a given time period within the packet frame; and an edge polarity to specify a rising or falling edge for the signal at the edge location.
23. A method, comprising: converting a first SER-DES input serial data stream into first SER-DES output signals; converting first SER-DES input signals into a first SER-DES output serial data stream; converting a second SER-DES input serial data stream into second SER-DES output signals; converting second SER-DES input signals into a second SER-DES output serial data stream; coupling the first SER-DES output serial data stream to the second SER-DES input serial data stream across a first galvanic isolation barrier to communicate control signals from a motor controller module to a motor drive power module to control a motor; and coupling the second SER-DES output serial data stream to the first SER-DES input serial data stream across a second galvanic isolation barrier to communicate feedback signals to the motor controller module from the motor drive power module relating to status of the motor.
24. The method of claim 23, further comprising formatting a packet frame to be communicated in the output serial data stream, the packet frame including: data that specifies an edge location for a signal to begin at a given time period within the packet frame; and an edge polarity that specifies a rising or falling edge for the signal at the edge location.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0007]
[0008]
[0009]
[0010]
[0011]
[0012]
[0013]
[0014]
[0015]
DETAILED DESCRIPTION
[0016] This description relates to serializer-deserializer systems and methods, such as for communicating controller and power signals of a motor drive circuit. Parallel signals can be grouped and serialized into a serial data stream at one end of the motor drive circuit and de-serialized into parallel signals at the other end, in order reduce isolation circuits between a motor controller module and a motor drive power module. For example, a separate serial-deserializer (SER-DES) module can be coupled respectively to the motor controller module and the motor drive power module, where the respective SER-DES module converts parallel signals from each of the modules into serial data streams, which are multiplexed (e.g., via time-division or frequency division multiplexing) to maintain synchronization between the controller and the power module.
[0017] Parallel signals can be classified according to an isolation domain in order to determine parallel signal groupings that can be multiplexed into a serial data stream at one end and de-multiplexed at the other end. For the example of a multi-phase motor, an isolation domain is defined by the signals that drive the motor, where each phase of the motor can include a high-side drive signal and a low-side drive signal to control the respective phase. In the example of a three-phase motor, two isolation domains can be specified per phase providing up to six isolation domains in three-phase inverters for motor drives. Isolation domains can also be extended to multilevel inverters with more than two switches per half-bridge. For example, a three-level neutral point clamped (NPC) inverter includes four switches in series per half-bridge which can similarly be supported. Each isolation domain may encompass multiple independent isolation channels (e.g. gate driver control signals, feedback signals from analog or digital current and voltage sensors for a given high or low side circuit that drives a motor phase). The isolation channels are expensive and use a fixed amount of board area for isolation requirements to provide safety spacing. The SER-DES module described herein enables a single (or reduced number) of isolation channels compared to many existing approaches. The approach herein further simplifies design of an isolated three-phase inverter power stage, reduces both silicon cost and PCB board space, and therefore reduces overall system cost of an isolated three-phase inverter.
[0018] The number of isolation channels can be reduced by grouping signals which share the same isolation domain within a multi-phase inverter system. The signals in each of the groups are multiplexed, passed through a reduced number of high speed isolated channels and then de-multiplexed again via the SER-DES modules. This grouping of signals allows new isolator integrated circuit topologies for isolated three-phase inverters, which enable smaller footprint and lower-cost multi-phase inverter designs.
[0019] The SER-DES modules can be configured to provide grouping and structuring for the signaling of the individual isolation domains by coupling to an isolation barrier for each of the different domains. A centralized isolation barrier per domain allows the end user to use lower-cost non-isolated gate drivers, analog-to-digital converter (ADC), or sensor frontends while fulfilling similar isolation requirements at lower system cost and less board space. Furthermore, the SER-DES modules limit the isolation components and therefore reduce silicon manufacturing cost for each circuit.
[0020] As used herein, the term circuit can include a collection of active and/or passive elements that perform a circuit function, such as an analog circuit or control circuit. Additionally or alternatively, for example, the term circuit can include an integrated circuit (IC) where all and/or some of the circuit elements are fabricated on a common substrate (e.g., semiconductor substrate, such as a die or chip).
[0021]
[0022] Example outputs of the motor controller module 104 include pulse width modulated (PWM) drive signals to drive high and low-side drivers of a three-phase motor and clock signals to be used by power module ADC circuits that digitize motor feedback information such as phase current detected in a given winding of the three-phase motor. One or more groupings (e.g., sets) of the outputs from the motor controller module 104 can be serialized and de-serialized by the motor drive communication circuit 108 and received by the motor drive power module 112 as inputs to control the three-phase motor. Additionally or alternatively, one or more groupings of outputs from the motor drive power module 112 can be serialized and de-serialized by the motor drive communication circuit 108 and received by the controller module 104 as inputs. Example outputs from the power module 112 can include serial analog-to-digital (ADC) signals representing phase current and/or voltage, diagnostic information including phase fault status and motor power status.
[0023] The motor drive communication circuit 108 includes a first SER-DES module 116 that converts a first SER-DES input serial data stream (FSDM RX IN) into first SER-DES output signals (FSDM O1 through FSDM ON) which in turn drive the inputs of the motor controller module 104. Additionally or alternatively, the first SER-DES module 116 converts first SER-DES input signals (FSDM I1 through FSDM IM) into a first SER-DES output serial data stream (FSDM XMIT OUT). As shown, the first SER-DES output signals (FSDM O1 through FSDM ON) are associated with motor controller inputs and the first SER-DES input signals (FSDM I1 through FSDM IM) are associated with motor controller outputs.
[0024] A second SER-DES module 120 converts a second SER-DES input serial data stream (SSDM RX IN) into second SER-DES output signals (SSDM O1 through SSDM OM), which provide corresponding inputs the power module 112. Additionally or alternatively, the second SER-DES module 120 converts second SER-DES input signals (SSDM I1 through SSDM IN) into a second SER-DES output serial data stream (SSDM XMIT OUT). The second SER-DES output signals (SSDM O1 through SSDM OM) are associated with motor drive power inputs and the second SER-DES input signals (SSDM I1 through SSDM IN) are associated with motor drive power outputs. Each of the SER-DES modules 116 and 120 can include a configuration input (CONFIG) which allows a user to program which connections of the motor controller module 104 and the motor drive power module 112 are connected to the respective SER-DES modules as inputs or outputs.
[0025] One or more serial isolation channels 124 and 128 provide communication through a galvanic isolation barrier 130 between the first SER-DES module 116 and the second SER-DES module 120. The serial isolation channel 124 communicates the first SER-DES output serial data stream (FSDM XMIT OUT) in one direction across the galvanic isolation barrier 130 to provide the second SER-DES input serial data stream (SSDM RX IN). The serial isolation channel 128 communicates the second SER-DES output serial data stream (SSDM XMIT OUT) in another direction across the galvanic isolation barrier 130 to provide the first SER-DES input serial data stream (FSDM RX IN). The isolation channels 124 and 128 can include substantially any type circuit that allows communication of signals from one side of the galvanic isolation barrier 130 to the other without also sharing common direct current (DC) paths, such as ground. Example isolation channels can include capacitive isolators, transformers, Hall effect isolators and optical isolators. The first and second SER-DES modules 116 and 120 and the serial isolation channels 124 and 128 can be implemented on an integrated circuit substrate in one example or a printed circuit board substrate in another example. Other example aspects of the respective SER-DES modules is illustrated and described hereinbelow with respect to
[0026]
[0027] The SER-DES module 200 includes an input stage 224 to encode data received from the input circuits 216 into an output serial data stream XMIT SERIAL OUT. A transmit shift register 228 is coupled to the input stage 224 to transmit the output serial data stream XMIT SERIAL OUT via the serial isolation channel described herein. A receive shift register 232 receives an input serial data stream RX SERIAL IN from the isolation channel described herein. An output stage 236 is coupled to the receive shift register 232 to decode the serial input data stream RX SERIAL IN and to provide parallel signals to the output circuits 220 that drive module inputs of the respective controller or power module. The input stage 224 encodes and formats a packet frame (see e.g.,
[0028] As an example, the packet frame includes data that specifies an edge location for a signal to begin at a given time period within the packet frame and an edge polarity that specifies a rising or falling edge for the signal at the edge location. The packet frame can be formatted according to a time division multiplexing (TDM) protocol in one example or a frequency division multiplexing (FDM) protocol in another example. A phased-locked loop (PLL) 240 can be provided to synchronize timing transmitted within the serial data streams communicated between the respective modules. The PLL 240 receives an input clock CLK IN from the respective controller or power module and generates an output clock CLK OUT to drive the SER-DES module 200.
[0029]
[0030] As a further example, the packet frame 300 can be transmitted at approximately 1 Gbps across the isolation boundary. A protocol can be developed across the two sides (e.g., using the serial channel) to coordinate and transmit low bit rate feedback and other general purpose input/output (GPIO) data. If the 14 bit frame is formatted in this example and transmitted, the latency will be about at least 28 nsec, but most likely less than about 50 nsec. When no edges exist to transmit, the polarity bits are redundant and could be used for exception processing, but an all zero transmission can be transmitted to conserve energy of the channel and reduce power when no edges exist. Even though the PWM signal could be approximately 100 KHz, frames can still exist where no bits are being transmitted. This achieves an example jitter target (e.g., +/2 nsec), latency e.g., <50 nsec, and is power efficient.
[0031]
[0032] Referring to
[0033] Referring to
[0034] A phase locked loop (PLL) 540 and 550 can be provided in each die 510, 520 to synchronize timing of signals in the respective SER-DES modules. Similar to
[0035] Referring to
[0036] Referring
[0037]
[0038] In view of the foregoing structural and functional features described hereinabove, an example method is described with reference to
[0039]
[0040] In this description, the term based on means based at least in part on. Modifications are possible in the described embodiments, and other embodiments are possible, within the scope of the claims.