How to plot time intervals without date components on the x-axis using dygraph and xts function?

Question

I'm trying to plot time series with the dygraph function. A single diagram represents the course of a specific variable on different days. Since series correspond to different days, I would like the x-axis to be date-agnostic. It should only contain time-intervals.

When I generate a time sequence with:

ts <- seq(as.POSIXct("2017-01-01 00:00:00"),as.POSIXct("2017-01-01 23:30:00"), by = "30 min")

and make a plot using it:

d <- data.frame(
    time = ts,
    profile1 = ...,
    profile2 = ...,
    profile3 = ...
  )
  
  don=xts(x=d[,c("profile1", "profile2", "profile3")], order.by=d$time)

I obtain a date used for creating the time sequence on the axis, which is not desirable:

I combed through the SO, looking for a method to obtain only time intervals from dates but presented methods do not help - results are rejected by the order.by component of the xts(...) function.

I have tried the following (ts is the sequence defined above):

1. strftime(ts, format = "%H:%M:%S") -> Error: order.by requires an appropriate time-based object

2. chron

ts <- chron(times. = ts)
Error in convert.times(times., fmt) : format h:m:s may be incorrect
Additionaly: Warning:
In convert.times(times., fmt) : NAs obtained

3. 1 & 2 combined:

  ts <- strftime(ts, format = "%H:%M:%S")
  ts <- chron(times. = ts)
Fehler in as.POSIXct.default(order.by) : 
  do not know how to convert 'order.by' to class “POSIXct”

Moreover, I would like the x-axis to be formatted in such a way that it shows the timespan between 00:00 to 00:00 if possible. Right now, as you can see in the picture, it starts with a date and ends without any interval info, there is just an empty space there.